"jeremy.brews***@akqa.com" wrote:

> Hello
>
> I'm trying to work out how to call a custom evaluation function for a
> Validation Control (via the "evaluationfunction" attribute) to change
> the visual style of the div hosting the input control if validation
> fails.  We have this working as a fallback on the server-side (if
> client-side script is turned off) but want/need this working on the
> client-side also.
>
> I am working on a website which included this behaviour in .NET 1.1 but
> I am having trouble getting it to work with .NET 2.0.
>
> I've tried setting the evaluation function using:
> this.validator.Attributes["evaluationfunction"] in the server-side
> helper class that includes an instance of the validator but this seems
> to be ignored by the browser and does not result in the client-side
> function being called.  When I use:
> this.validator.Page.ClientScript.RegisterExpandoAttribute("...") I
> receive an error stating "System.ArgumentException: An entry with the
> same key already exists."
>
> Indeed when we use the DOM Inspector from Firefox on the page we can
> see that the evaluationfunction attribute for the validator already has
> the following out-of-the-box client-script defined:
>
> function RegularExpressionValidatorEvaluateIsValid(val) {
>     var value = ValidatorGetValue(val.controltovalidate);
>     if (ValidatorTrim(value).length == 0) {
>         return true;
>     }
>     var rx = new RegExp(val.validationexpression);
>     var matches = rx.exec(value);
>     return (matches != null && value == matches[0]);
> }
>
> So I'm thinking that what I need is the ability to change the
> evaluationfunction value to my own custom code.  I'm having no luck
> whatsoever with this.
>
> Does anybody have any ideas on how to solve this.  Thanks in advance.
>
> Jez
>
>

> You could write a custom validator that implements the BaseValidator. Then if
> you override AddAttributesToRender use
> Page.ClientScript.RegisterExpandoAttribute(ClientID, "evaluationfunction",
> "ClientSideFunctionToCall", false); and it should work.
>
> "jeremy.brews***@akqa.com" wrote:
>
> > Hello
> >
> > I'm trying to work out how to call a custom evaluation function for a
> > Validation Control (via the "evaluationfunction" attribute) to change
> > the visual style of the div hosting the input control if validation
> > fails.  We have this working as a fallback on the server-side (if
> > client-side script is turned off) but want/need this working on the
> > client-side also.
> >
> > I am working on a website which included this behaviour in .NET 1.1 but
> > I am having trouble getting it to work with .NET 2.0.
> >
> > I've tried setting the evaluation function using:
> > this.validator.Attributes["evaluationfunction"] in the server-side
> > helper class that includes an instance of the validator but this seems
> > to be ignored by the browser and does not result in the client-side
> > function being called.  When I use:
> > this.validator.Page.ClientScript.RegisterExpandoAttribute("...") I
> > receive an error stating "System.ArgumentException: An entry with the
> > same key already exists."
> >
> > Indeed when we use the DOM Inspector from Firefox on the page we can
> > see that the evaluationfunction attribute for the validator already has
> > the following out-of-the-box client-script defined:
> >
> > function RegularExpressionValidatorEvaluateIsValid(val) {
> >     var value = ValidatorGetValue(val.controltovalidate);
> >     if (ValidatorTrim(value).length == 0) {
> >         return true;
> >     }
> >     var rx = new RegExp(val.validationexpression);
> >     var matches = rx.exec(value);
> >     return (matches != null && value == matches[0]);
> > }
> >
> > So I'm thinking that what I need is the ability to change the
> > evaluationfunction value to my own custom code.  I'm having no luck
> > whatsoever with this.
> >
> > Does anybody have any ideas on how to solve this.  Thanks in advance.
> >
> > Jez
> >
> >

news:1151058013.109033.231650@m73g2000cwd.googlegroups.com...
> Hi Jim
>
> Thanks for the reply.  This is something we are already doing.  We have
> subclassed each validator for which we want to create a customised
> behaviour.  So we have a class with the following definition:
>
> public class StyleChangingRequiredFieldValidator :
> RequiredFieldValidator
> {
> private StyleChangingHelper helper;
>
> /// <summary>
> /// Default constructor.
> /// </summary>
> public StyleChangingRequiredFieldValidator()
> {
> this.helper = new StyleChangingHelper(this);
> }
>
> /// <summary>
> /// The control whose style should be changed when validation results
> in an invalid state.
> /// </summary>
> public string ControlToChange
> {
> get
> {
> return this.helper.ControlToChange;
> }
> set
> {
> this.helper.ControlToChange = value;
> }
> }
>
> /// <summary>
> /// The CSS class to use when changing the style of the targeted
> control.
> /// </summary>
> public string ChangeCssClass
> {
> get
> {
> return this.helper.ChangeCssClass;
> }
> set
> {
> this.helper.ChangeCssClass = value;
> }
> }
>
> /// <summary>
> /// Raises the Init event.
> /// </summary>
> /// <param name="e">An EventArgs object that contains the event
> data.</param>
> protected override void OnInit(System.EventArgs e)
> {
> base.OnInit(e);
> this.helper.OnInit(e);
> }
>
> /// <summary>
> /// Determines whether the value in the input control is valid.
> /// </summary>
> /// <returns><c>true</c> if the value in the input control is valid;
> otherwise, <c>false</c>.</returns>
> protected override bool EvaluateIsValid()
> {
> bool isValid = base.EvaluateIsValid();
> return this.helper.EvaluateIsValid(isValid);
> }
>
> /// <summary>
> /// Raises the PreRender event.
> /// </summary>
> /// <param name="e">An EventArgs object that contains the event
> data.</param>
> protected override void OnPreRender(System.EventArgs e)
> {
> this.helper.OnPreRender(e);
> base.OnPreRender(e);
> }
>
> /// <summary>
> /// Adds HTML attributes and styles that need to be rendered to the
> specified System.Web.UI.HtmlTextWriter.
> /// </summary>
> /// <param name="writer">A System.Web.UI.HtmlTextWriter that
> represents the output stream to render HTML content on the
> client.</param>
> protected override void AddAttributesToRender(HtmlTextWriter writer)
> {
> base.AddAttributesToRender(writer);
> this.helper.AddAttributesToRender(writer, this.RenderUplevel);
> }
> }
>
> We have created a StyleChangingHelper class, an instance of which is
> instantiated by each Validator derived subclass, and objects based on
> this class handle the writing of the attributes.
>
> /// <summary>
> /// Provides functionality for style changing validation controls.
> /// </summary>
> public class StyleChangingHelper
> {
> private BaseValidator validator;
> private string controlToChange;
> private string changeCssClass;
> private object foundControl;
> private string originalCssClass;
> private const string evaluationFunctionSuffix = "_Verify";
>
> /// <summary>
> /// Constructor which initialises the helper with a validator
> instance.
> /// </summary>
> /// <param name="validator">The validator that this helper will be
> helping.</param>
> public StyleChangingHelper(BaseValidator validator)
> {
> this.validator = validator;
> }
>
> /// <summary>
> /// The control whose style should be changed when validation results
> in an invalid state.
> /// </summary>
> public string ControlToChange
> {
> get
> {
> return this.controlToChange;
> }
> set
> {
> this.controlToChange = value;
> }
> }
>
> /// <summary>
> /// The CSS class to use when changing the style of the targeted
> control.
> /// </summary>
> public string ChangeCssClass
> {
> get
> {
> return this.changeCssClass;
> }
> set
> {
> this.changeCssClass = value;
> }
> }
>
> /// <summary>
> /// Should be called by the base validator upon raising the Init
> event.
> /// </summary>
> /// <param name="e">An EventArgs object that contains the event
> data.</param>
> public void OnInit(System.EventArgs e)
> {
>                               string controlID = DeriveId('$');
>
> this.foundControl = this.validator.Page.FindControl(controlID);
> if (this.foundControl != null)
> {
> if (this.foundControl is WebControl)
> {
> WebControl foundWebControl = (WebControl) this.foundControl;
> this.originalCssClass = foundWebControl.CssClass;
> }
> else if (foundControl is HtmlControl)
> {
> HtmlControl foundHtmlControl = (HtmlControl) this.foundControl;
> this.originalCssClass = foundHtmlControl.Attributes["class"];
> }
> }
> }
>
> /// <summary>
> /// Determines whether the value in the input control is valid.
> /// </summary>
> /// <param name="isValid">Indicates whether the calling validator
> considers the input control valid.</param>
> public bool EvaluateIsValid(bool isValid)
> {
> if (!isValid)
> {
> if (this.foundControl != null)
> {
> if (this.foundControl is WebControl)
> {
> WebControl foundWebControl = (WebControl) this.foundControl;
>
> foundWebControl.CssClass = this.changeCssClass;
> }
> else if (foundControl is HtmlControl)
> {
> HtmlControl foundHtmlControl = (HtmlControl) this.foundControl;
> foundHtmlControl.Attributes.Add("class", this.changeCssClass);
> }
> }
> }
> return isValid;
> }
>
> /// <summary>
> /// Should be called by the base validator upon raising the PreRender
> event.
> /// </summary>
> /// <param name="e">An EventArgs object that contains the event
> data.</param>
> public void OnPreRender(System.EventArgs e)
> {
> if (this.validator.EnableClientScript)
> {
> // this.validator.Attributes["evaluationfunction"] =
> this.validator.GetType().Name + evaluationFunctionSuffix;
>
>
>
> this.validator.Page.ClientScript.RegisterExpandoAttribute(validator.ClientID,
> "evaluationfunction", this.validator.GetType().Name +
> evaluationFunctionSuffix);
> }
> }
>
> /// <summary>
> /// Adds HTML attributes and styles that need to be rendered to the
> specified System.Web.UI.HtmlTextWriter.
> /// </summary>
> /// <param name="writer">A System.Web.UI.HtmlTextWriter that
> represents the output stream to render HTML content on the
> client.</param>
> /// <param name="renderUpLevel">Indicates whether the client's browser
> supports uplevel rendering.</param>
> public void AddAttributesToRender(HtmlTextWriter writer, bool
> renderUpLevel)
> {
> if (renderUpLevel)
> {
> string renderedControlID;
>                                                renderedControlID =
> DeriveId('_');
>
>                 writer.AddAttribute("controltochange",
> renderedControlID);
> writer.AddAttribute("changecssclass", ChangeCssClass);
> writer.AddAttribute("originalcssclass", this.originalCssClass);
> }
> }
> }
>
> When I compile and run this code, we receive a
> "System.ArgumentException: An entry with the same key already exists."
> highlighting the AddAttributesToRender method in the
> StyleChangingRequiredFieldValidator class.
>
> If I don't use the Page.ClientScript.RegisterExpandoAttribute method to
> write the evaluationfunction attribute (instead using:
> validator.Attributes["evaluationfunction"] = ...) then the value
> written is effectively ignored by the web page (although written to the
> page html as observed in notepad).  When I say that it is ignored by
> the web page, I know this from running the Firefox DOM Inspector which
> states that the ASP.NET out-of-the-box required field validator
> function is being used.
>
> function RequiredFieldValidatorEvaluateIsValid(val) {
>    return (ValidatorTrim(ValidatorGetValue(val.controltovalidate)) !=
> ValidatorTrim(val.initialvalue));
> }
>
> So I'm again stuck with not being able to replace the out-of-the-box
> javascript evaluationfunction value with my own custom implementation
> in which I want to dynamically change the style of the div elements
> hosting the input control should validation fail.
>
> Does anybody have any ideas?
>
> Thanks
>
> Jez
>
>
> JimOx wrote:
>> You could write a custom validator that implements the BaseValidator.
>> Then if
>> you override AddAttributesToRender use
>> Page.ClientScript.RegisterExpandoAttribute(ClientID,
>> "evaluationfunction",
>> "ClientSideFunctionToCall", false); and it should work.
>>
>> "jeremy.brews***@akqa.com" wrote:
>>
>> > Hello
>> >
>> > I'm trying to work out how to call a custom evaluation function for a
>> > Validation Control (via the "evaluationfunction" attribute) to change
>> > the visual style of the div hosting the input control if validation
>> > fails.  We have this working as a fallback on the server-side (if
>> > client-side script is turned off) but want/need this working on the
>> > client-side also.
>> >
>> > I am working on a website which included this behaviour in .NET 1.1 but
>> > I am having trouble getting it to work with .NET 2.0.
>> >
>> > I've tried setting the evaluation function using:
>> > this.validator.Attributes["evaluationfunction"] in the server-side
>> > helper class that includes an instance of the validator but this seems
>> > to be ignored by the browser and does not result in the client-side
>> > function being called.  When I use:
>> > this.validator.Page.ClientScript.RegisterExpandoAttribute("...") I
>> > receive an error stating "System.ArgumentException: An entry with the
>> > same key already exists."
>> >
>> > Indeed when we use the DOM Inspector from Firefox on the page we can
>> > see that the evaluationfunction attribute for the validator already has
>> > the following out-of-the-box client-script defined:
>> >
>> > function RegularExpressionValidatorEvaluateIsValid(val) {
>> >     var value = ValidatorGetValue(val.controltovalidate);
>> >     if (ValidatorTrim(value).length == 0) {
>> >         return true;
>> >     }
>> >     var rx = new RegExp(val.validationexpression);
>> >     var matches = rx.exec(value);
>> >     return (matches != null && value == matches[0]);
>> > }
>> >
>> > So I'm thinking that what I need is the ability to change the
>> > evaluationfunction value to my own custom code.  I'm having no luck
>> > whatsoever with this.
>> >
>> > Does anybody have any ideas on how to solve this.  Thanks in advance.
>> >
>> > Jez
>> >
>> >
>

> hi Jeremy, in your override of AddAttributesToRender, do not call
> base.AddAttributesToRender. Instead what you need to do is override this
> method as you are currently doing and add apply your customized attributes
> to it, which is probably being done via the method call to your helper
> class.
>
> Regards,
> Alessandro Zifiglio
> <jeremy.brews***@akqa.com> ha scritto nel messaggio
> news:1151058013.109033.231650@m73g2000cwd.googlegroups.com...
> > Hi Jim
> >
> > Thanks for the reply.  This is something we are already doing.  We have
> > subclassed each validator for which we want to create a customised
> > behaviour.  So we have a class with the following definition:
> >
> > public class StyleChangingRequiredFieldValidator :
> > RequiredFieldValidator
> > {
> > private StyleChangingHelper helper;
> >
> > /// <summary>
> > /// Default constructor.
> > /// </summary>
> > public StyleChangingRequiredFieldValidator()
> > {
> > this.helper = new StyleChangingHelper(this);
> > }
> >
> > /// <summary>
> > /// The control whose style should be changed when validation results
> > in an invalid state.
> > /// </summary>
> > public string ControlToChange
> > {
> > get
> > {
> > return this.helper.ControlToChange;
> > }
> > set
> > {
> > this.helper.ControlToChange = value;
> > }
> > }
> >
> > /// <summary>
> > /// The CSS class to use when changing the style of the targeted
> > control.
> > /// </summary>
> > public string ChangeCssClass
> > {
> > get
> > {
> > return this.helper.ChangeCssClass;
> > }
> > set
> > {
> > this.helper.ChangeCssClass = value;
> > }
> > }
> >
> > /// <summary>
> > /// Raises the Init event.
> > /// </summary>
> > /// <param name="e">An EventArgs object that contains the event
> > data.</param>
> > protected override void OnInit(System.EventArgs e)
> > {
> > base.OnInit(e);
> > this.helper.OnInit(e);
> > }
> >
> > /// <summary>
> > /// Determines whether the value in the input control is valid.
> > /// </summary>
> > /// <returns><c>true</c> if the value in the input control is valid;
> > otherwise, <c>false</c>.</returns>
> > protected override bool EvaluateIsValid()
> > {
> > bool isValid = base.EvaluateIsValid();
> > return this.helper.EvaluateIsValid(isValid);
> > }
> >
> > /// <summary>
> > /// Raises the PreRender event.
> > /// </summary>
> > /// <param name="e">An EventArgs object that contains the event
> > data.</param>
> > protected override void OnPreRender(System.EventArgs e)
> > {
> > this.helper.OnPreRender(e);
> > base.OnPreRender(e);
> > }
> >
> > /// <summary>
> > /// Adds HTML attributes and styles that need to be rendered to the
> > specified System.Web.UI.HtmlTextWriter.
> > /// </summary>
> > /// <param name="writer">A System.Web.UI.HtmlTextWriter that
> > represents the output stream to render HTML content on the
> > client.</param>
> > protected override void AddAttributesToRender(HtmlTextWriter writer)
> > {
> > base.AddAttributesToRender(writer);
> > this.helper.AddAttributesToRender(writer, this.RenderUplevel);
> > }
> > }
> >
> > We have created a StyleChangingHelper class, an instance of which is
> > instantiated by each Validator derived subclass, and objects based on
> > this class handle the writing of the attributes.
> >
> > /// <summary>
> > /// Provides functionality for style changing validation controls.
> > /// </summary>
> > public class StyleChangingHelper
> > {
> > private BaseValidator validator;
> > private string controlToChange;
> > private string changeCssClass;
> > private object foundControl;
> > private string originalCssClass;
> > private const string evaluationFunctionSuffix = "_Verify";
> >
> > /// <summary>
> > /// Constructor which initialises the helper with a validator
> > instance.
> > /// </summary>
> > /// <param name="validator">The validator that this helper will be
> > helping.</param>
> > public StyleChangingHelper(BaseValidator validator)
> > {
> > this.validator = validator;
> > }
> >
> > /// <summary>
> > /// The control whose style should be changed when validation results
> > in an invalid state.
> > /// </summary>
> > public string ControlToChange
> > {
> > get
> > {
> > return this.controlToChange;
> > }
> > set
> > {
> > this.controlToChange = value;
> > }
> > }
> >
> > /// <summary>
> > /// The CSS class to use when changing the style of the targeted
> > control.
> > /// </summary>
> > public string ChangeCssClass
> > {
> > get
> > {
> > return this.changeCssClass;
> > }
> > set
> > {
> > this.changeCssClass = value;
> > }
> > }
> >
> > /// <summary>
> > /// Should be called by the base validator upon raising the Init
> > event.
> > /// </summary>
> > /// <param name="e">An EventArgs object that contains the event
> > data.</param>
> > public void OnInit(System.EventArgs e)
> > {
> >                               string controlID = DeriveId('$');
> >
> > this.foundControl = this.validator.Page.FindControl(controlID);
> > if (this.foundControl != null)
> > {
> > if (this.foundControl is WebControl)
> > {
> > WebControl foundWebControl = (WebControl) this.foundControl;
> > this.originalCssClass = foundWebControl.CssClass;
> > }
> > else if (foundControl is HtmlControl)
> > {
> > HtmlControl foundHtmlControl = (HtmlControl) this.foundControl;
> > this.originalCssClass = foundHtmlControl.Attributes["class"];
> > }
> > }
> > }
> >
> > /// <summary>
> > /// Determines whether the value in the input control is valid.
> > /// </summary>
> > /// <param name="isValid">Indicates whether the calling validator
> > considers the input control valid.</param>
> > public bool EvaluateIsValid(bool isValid)
> > {
> > if (!isValid)
> > {
> > if (this.foundControl != null)
> > {
> > if (this.foundControl is WebControl)
> > {
> > WebControl foundWebControl = (WebControl) this.foundControl;
> >
> > foundWebControl.CssClass = this.changeCssClass;
> > }
> > else if (foundControl is HtmlControl)
> > {
> > HtmlControl foundHtmlControl = (HtmlControl) this.foundControl;
> > foundHtmlControl.Attributes.Add("class", this.changeCssClass);
> > }
> > }
> > }
> > return isValid;
> > }
> >
> > /// <summary>
> > /// Should be called by the base validator upon raising the PreRender
> > event.
> > /// </summary>
> > /// <param name="e">An EventArgs object that contains the event
> > data.</param>
> > public void OnPreRender(System.EventArgs e)
> > {
> > if (this.validator.EnableClientScript)
> > {
> > // this.validator.Attributes["evaluationfunction"] =
> > this.validator.GetType().Name + evaluationFunctionSuffix;
> >
> >
> >
> > this.validator.Page.ClientScript.RegisterExpandoAttribute(validator.ClientID,
> > "evaluationfunction", this.validator.GetType().Name +
> > evaluationFunctionSuffix);
> > }
> > }
> >
> > /// <summary>
> > /// Adds HTML attributes and styles that need to be rendered to the
> > specified System.Web.UI.HtmlTextWriter.
> > /// </summary>
> > /// <param name="writer">A System.Web.UI.HtmlTextWriter that
> > represents the output stream to render HTML content on the
> > client.</param>
> > /// <param name="renderUpLevel">Indicates whether the client's browser
> > supports uplevel rendering.</param>
> > public void AddAttributesToRender(HtmlTextWriter writer, bool
> > renderUpLevel)
> > {
> > if (renderUpLevel)
> > {
> > string renderedControlID;
> >                                                renderedControlID =
> > DeriveId('_');
> >
> >                 writer.AddAttribute("controltochange",
> > renderedControlID);
> > writer.AddAttribute("changecssclass", ChangeCssClass);
> > writer.AddAttribute("originalcssclass", this.originalCssClass);
> > }
> > }
> > }
> >
> > When I compile and run this code, we receive a
> > "System.ArgumentException: An entry with the same key already exists."
> > highlighting the AddAttributesToRender method in the
> > StyleChangingRequiredFieldValidator class.
> >
> > If I don't use the Page.ClientScript.RegisterExpandoAttribute method to
> > write the evaluationfunction attribute (instead using:
> > validator.Attributes["evaluationfunction"] = ...) then the value
> > written is effectively ignored by the web page (although written to the
> > page html as observed in notepad).  When I say that it is ignored by
> > the web page, I know this from running the Firefox DOM Inspector which
> > states that the ASP.NET out-of-the-box required field validator
> > function is being used.
> >
> > function RequiredFieldValidatorEvaluateIsValid(val) {
> >    return (ValidatorTrim(ValidatorGetValue(val.controltovalidate)) !=
> > ValidatorTrim(val.initialvalue));
> > }
> >
> > So I'm again stuck with not being able to replace the out-of-the-box
> > javascript evaluationfunction value with my own custom implementation
> > in which I want to dynamically change the style of the div elements
> > hosting the input control should validation fail.
> >
> > Does anybody have any ideas?
> >
> > Thanks
> >
> > Jez
> >
> >
> > JimOx wrote:
> >> You could write a custom validator that implements the BaseValidator.
> >> Then if
> >> you override AddAttributesToRender use
> >> Page.ClientScript.RegisterExpandoAttribute(ClientID,
> >> "evaluationfunction",
> >> "ClientSideFunctionToCall", false); and it should work.
> >>
> >> "jeremy.brews***@akqa.com" wrote:
> >>
> >> > Hello
> >> >
> >> > I'm trying to work out how to call a custom evaluation function for a
> >> > Validation Control (via the "evaluationfunction" attribute) to change
> >> > the visual style of the div hosting the input control if validation
> >> > fails.  We have this working as a fallback on the server-side (if
> >> > client-side script is turned off) but want/need this working on the
> >> > client-side also.
> >> >
> >> > I am working on a website which included this behaviour in .NET 1.1 but
> >> > I am having trouble getting it to work with .NET 2.0.
> >> >
> >> > I've tried setting the evaluation function using:
> >> > this.validator.Attributes["evaluationfunction"] in the server-side
> >> > helper class that includes an instance of the validator but this seems
> >> > to be ignored by the browser and does not result in the client-side
> >> > function being called.  When I use:
> >> > this.validator.Page.ClientScript.RegisterExpandoAttribute("...") I
> >> > receive an error stating "System.ArgumentException: An entry with the
> >> > same key already exists."
> >> >
> >> > Indeed when we use the DOM Inspector from Firefox on the page we can
> >> > see that the evaluationfunction attribute for the validator already has
> >> > the following out-of-the-box client-script defined:
> >> >
> >> > function RegularExpressionValidatorEvaluateIsValid(val) {
> >> >     var value = ValidatorGetValue(val.controltovalidate);
> >> >     if (ValidatorTrim(value).length == 0) {
> >> >         return true;
> >> >     }
> >> >     var rx = new RegExp(val.validationexpression);
> >> >     var matches = rx.exec(value);
> >> >     return (matches != null && value == matches[0]);
> >> > }
> >> >
> >> > So I'm thinking that what I need is the ability to change the
> >> > evaluationfunction value to my own custom code.  I'm having no luck
> >> > whatsoever with this.
> >> >
> >> > Does anybody have any ideas on how to solve this.  Thanks in advance.
> >> >
> >> > Jez
> >> >
> >> >
> >

"jeremy.brews***@akqa.com" wrote:

> Hi Alessando
>
> If I don't call the validator base.AddAttributesToRender then no aspect
> of the validator gets written to the page.
>
> As you say, I am overriding the AddAttributesToRender method in my
> custom validators and they do indeed call the StyleChangingHelper
> instance variable's method of the same name.
>
> MSDN states "Notes to Inheritors When overriding the
> AddAttributesToRender method, be sure to call the corresponding method
> in the base class. Otherwise, the attributes contained in the base
> class will not be rendered."
>
> Or are you suggesting that my override that does not call the base
> implementation needs to do more than it is doing at the minute?
>
> The StyleChangingRequiredFieldValidator has the following OnPreRender
> and AddAttributesToRender methods:
>
> /// <summary>
> /// Raises the PreRender event.
> /// </summary>
> /// <param name="e">An EventArgs object that contains the event
> data.</param>
> protected override void OnPreRender(System.EventArgs e)
> {
>     this.helper.OnPreRender(e);
>     base.OnPreRender(e);
> }
>
> /// <summary>
> /// Adds HTML attributes and styles that need to be rendered to the
> specified System.Web.UI.HtmlTextWriter.
> /// </summary>
> /// <param name="writer">A System.Web.UI.HtmlTextWriter that represents
> the output stream to render HTML content on the client.</param>
> protected override void AddAttributesToRender(HtmlTextWriter writer)
> {
>     base.AddAttributesToRender(writer);
>     this.helper.AddAttributesToRender(writer, this.RenderUplevel);
> }
>
> The StyleChangingHelper has the following custom methods of the same
> names:
>
> /// <summary>
> /// Should be called by the base validator upon raising the PreRender
> event.
> /// </summary>
> /// <param name="e">An EventArgs object that contains the event
> data.</param>
> public void OnPreRender(System.EventArgs e)
> {
>     if (this.validator.EnableClientScript)
>     {
> //        this.validator.Attributes["evaluationfunction"] =
> this.validator.GetType().Name + evaluationFunctionSuffix;
> this.validator.Page.ClientScript.RegisterExpandoAttribute(validator.ClientID,
> "evaluationfunction", this.validator.GetType().Name +
> evaluationFunctionSuffix);
>     }
> }
>
> /// <summary>
> /// Adds HTML attributes and styles that need to be rendered to the
> specified System.Web.UI.HtmlTextWriter.
> /// </summary>
> /// <param name="writer">A System.Web.UI.HtmlTextWriter that represents
> the output stream to render HTML content on the client.</param>
> /// <param name="renderUpLevel">Indicates whether the client's browser
> supports uplevel rendering.</param>
> public void AddAttributesToRender(HtmlTextWriter writer, bool
> renderUpLevel)
> {
>     if (renderUpLevel)
>     {
>         string renderedControlID;
> renderedControlID = DeriveId('_');
>
>         writer.AddAttribute("controltochange", renderedControlID);
>         writer.AddAttribute("changecssclass", ChangeCssClass);
>         writer.AddAttribute("originalcssclass", this.originalCssClass);
>     }
> }
>
>
> Alessandro Zifiglio wrote:
> > hi Jeremy, in your override of AddAttributesToRender, do not call
> > base.AddAttributesToRender. Instead what you need to do is override this
> > method as you are currently doing and add apply your customized attributes
> > to it, which is probably being done via the method call to your helper
> > class.
> >
> > Regards,
> > Alessandro Zifiglio
> > <jeremy.brews***@akqa.com> ha scritto nel messaggio
> > news:1151058013.109033.231650@m73g2000cwd.googlegroups.com...
> > > Hi Jim
> > >
> > > Thanks for the reply.  This is something we are already doing.  We have
> > > subclassed each validator for which we want to create a customised
> > > behaviour.  So we have a class with the following definition:
> > >
> > > public class StyleChangingRequiredFieldValidator :
> > > RequiredFieldValidator
> > > {
> > > private StyleChangingHelper helper;
> > >
> > > /// <summary>
> > > /// Default constructor.
> > > /// </summary>
> > > public StyleChangingRequiredFieldValidator()
> > > {
> > > this.helper = new StyleChangingHelper(this);
> > > }
> > >
> > > /// <summary>
> > > /// The control whose style should be changed when validation results
> > > in an invalid state.
> > > /// </summary>
> > > public string ControlToChange
> > > {
> > > get
> > > {
> > > return this.helper.ControlToChange;
> > > }
> > > set
> > > {
> > > this.helper.ControlToChange = value;
> > > }
> > > }
> > >
> > > /// <summary>
> > > /// The CSS class to use when changing the style of the targeted
> > > control.
> > > /// </summary>
> > > public string ChangeCssClass
> > > {
> > > get
> > > {
> > > return this.helper.ChangeCssClass;
> > > }
> > > set
> > > {
> > > this.helper.ChangeCssClass = value;
> > > }
> > > }
> > >
> > > /// <summary>
> > > /// Raises the Init event.
> > > /// </summary>
> > > /// <param name="e">An EventArgs object that contains the event
> > > data.</param>
> > > protected override void OnInit(System.EventArgs e)
> > > {
> > > base.OnInit(e);
> > > this.helper.OnInit(e);
> > > }
> > >
> > > /// <summary>
> > > /// Determines whether the value in the input control is valid.
> > > /// </summary>
> > > /// <returns><c>true</c> if the value in the input control is valid;
> > > otherwise, <c>false</c>.</returns>
> > > protected override bool EvaluateIsValid()
> > > {
> > > bool isValid = base.EvaluateIsValid();
> > > return this.helper.EvaluateIsValid(isValid);
> > > }
> > >
> > > /// <summary>
> > > /// Raises the PreRender event.
> > > /// </summary>
> > > /// <param name="e">An EventArgs object that contains the event
> > > data.</param>
> > > protected override void OnPreRender(System.EventArgs e)
> > > {
> > > this.helper.OnPreRender(e);
> > > base.OnPreRender(e);
> > > }
> > >
> > > /// <summary>
> > > /// Adds HTML attributes and styles that need to be rendered to the
> > > specified System.Web.UI.HtmlTextWriter.
> > > /// </summary>
> > > /// <param name="writer">A System.Web.UI.HtmlTextWriter that
> > > represents the output stream to render HTML content on the
> > > client.</param>
> > > protected override void AddAttributesToRender(HtmlTextWriter writer)
> > > {
> > > base.AddAttributesToRender(writer);
> > > this.helper.AddAttributesToRender(writer, this.RenderUplevel);
> > > }
> > > }
> > >
> > > We have created a StyleChangingHelper class, an instance of which is
> > > instantiated by each Validator derived subclass, and objects based on
> > > this class handle the writing of the attributes.
> > >
> > > /// <summary>
> > > /// Provides functionality for style changing validation controls.
> > > /// </summary>
> > > public class StyleChangingHelper
> > > {
> > > private BaseValidator validator;
> > > private string controlToChange;
> > > private string changeCssClass;
> > > private object foundControl;
> > > private string originalCssClass;
> > > private const string evaluationFunctionSuffix = "_Verify";
> > >
> > > /// <summary>
> > > /// Constructor which initialises the helper with a validator
> > > instance.
> > > /// </summary>
> > > /// <param name="validator">The validator that this helper will be
> > > helping.</param>
> > > public StyleChangingHelper(BaseValidator validator)
> > > {
> > > this.validator = validator;
> > > }
> > >
> > > /// <summary>
> > > /// The control whose style should be changed when validation results
> > > in an invalid state.
> > > /// </summary>
> > > public string ControlToChange
> > > {
> > > get
> > > {
> > > return this.controlToChange;
> > > }
> > > set
> > > {
> > > this.controlToChange = value;
> > > }
> > > }
> > >
> > > /// <summary>
> > > /// The CSS class to use when changing the style of the targeted
> > > control.
> > > /// </summary>
> > > public string ChangeCssClass
> > > {
> > > get
> > > {
> > > return this.changeCssClass;
> > > }
> > > set
> > > {
> > > this.changeCssClass = value;
> > > }
> > > }
> > >
> > > /// <summary>
> > > /// Should be called by the base validator upon raising the Init
> > > event.
> > > /// </summary>
> > > /// <param name="e">An EventArgs object that contains the event
> > > data.</param>
> > > public void OnInit(System.EventArgs e)
> > > {
> > >                               string controlID = DeriveId('$');
> > >
> > > this.foundControl = this.validator.Page.FindControl(controlID);
> > > if (this.foundControl != null)
> > > {
> > > if (this.foundControl is WebControl)
> > > {
> > > WebControl foundWebControl = (WebControl) this.foundControl;
> > > this.originalCssClass = foundWebControl.CssClass;
> > > }
> > > else if (foundControl is HtmlControl)
> > > {
> > > HtmlControl foundHtmlControl = (HtmlControl) this.foundControl;
> > > this.originalCssClass = foundHtmlControl.Attributes["class"];
> > > }
> > > }
> > > }
> > >
> > > /// <summary>
> > > /// Determines whether the value in the input control is valid.
> > > /// </summary>
> > > /// <param name="isValid">Indicates whether the calling validator
> > > considers the input control valid.</param>
> > > public bool EvaluateIsValid(bool isValid)
> > > {
> > > if (!isValid)
> > > {
> > > if (this.foundControl != null)
> > > {
> > > if (this.foundControl is WebControl)
> > > {
> > > WebControl foundWebControl = (WebControl) this.foundControl;
> > >
> > > foundWebControl.CssClass = this.changeCssClass;
> > > }
> > > else if (foundControl is HtmlControl)
> > > {

"JimOx" <Ji***@discussions.microsoft.com> ha scritto nel messaggio
news:B3AD086D-DE1E-4DC2-97F8-6B37534C30B3@microsoft.com...
> Jeremy,
>
> I believe that to do this you can go one of two ways.  Either don't call
> the
> base.AddAttributesToRender in your overriding method.  This will require
> you
> to have to manually register all of the attributes that the base class
> would
> have registered that you need.  The other option is to inherit from
> BaseValidator instead of RequiredFieldValidator.  This is because
> BaseValidator does not register the
> "evaluationfunction" attribute but RequiredFieldValidator does and as far
> as
> I know once an ExpandoAttribute is registered there is no way to change
> it's
> value or remove the original.
>
> As a side note you will need to use
> Page.ClientScript.RegisterExpandoAttribute to write the attribute instead
> of
> writer.AddAttribute.  This is because if you use writer.AddAttribute it
> will
> work in IE but not FireFox.  However
> Page.ClientScript.RegisterExpandoAttribute will work in both.
>
> "jeremy.brews***@akqa.com" wrote:
>
>> Hi Alessando
>>
>> If I don't call the validator base.AddAttributesToRender then no aspect
>> of the validator gets written to the page.
>>
>> As you say, I am overriding the AddAttributesToRender method in my
>> custom validators and they do indeed call the StyleChangingHelper
>> instance variable's method of the same name.
>>
>> MSDN states "Notes to Inheritors When overriding the
>> AddAttributesToRender method, be sure to call the corresponding method
>> in the base class. Otherwise, the attributes contained in the base
>> class will not be rendered."
>>
>> Or are you suggesting that my override that does not call the base
>> implementation needs to do more than it is doing at the minute?
>>
>> The StyleChangingRequiredFieldValidator has the following OnPreRender
>> and AddAttributesToRender methods:
>>
>> /// <summary>
>> /// Raises the PreRender event.
>> /// </summary>
>> /// <param name="e">An EventArgs object that contains the event
>> data.</param>
>> protected override void OnPreRender(System.EventArgs e)
>> {
>> this.helper.OnPreRender(e);
>> base.OnPreRender(e);
>> }
>>
>> /// <summary>
>> /// Adds HTML attributes and styles that need to be rendered to the
>> specified System.Web.UI.HtmlTextWriter.
>> /// </summary>
>> /// <param name="writer">A System.Web.UI.HtmlTextWriter that represents
>> the output stream to render HTML content on the client.</param>
>> protected override void AddAttributesToRender(HtmlTextWriter writer)
>> {
>> base.AddAttributesToRender(writer);
>> this.helper.AddAttributesToRender(writer, this.RenderUplevel);
>> }
>>
>> The StyleChangingHelper has the following custom methods of the same
>> names:
>>
>> /// <summary>
>> /// Should be called by the base validator upon raising the PreRender
>> event.
>> /// </summary>
>> /// <param name="e">An EventArgs object that contains the event
>> data.</param>
>> public void OnPreRender(System.EventArgs e)
>> {
>> if (this.validator.EnableClientScript)
>> {
>> // this.validator.Attributes["evaluationfunction"] =
>> this.validator.GetType().Name + evaluationFunctionSuffix;
>> this.validator.Page.ClientScript.RegisterExpandoAttribute(validator.ClientID,
>> "evaluationfunction", this.validator.GetType().Name +
>> evaluationFunctionSuffix);
>> }
>> }
>>
>> /// <summary>
>> /// Adds HTML attributes and styles that need to be rendered to the
>> specified System.Web.UI.HtmlTextWriter.
>> /// </summary>
>> /// <param name="writer">A System.Web.UI.HtmlTextWriter that represents
>> the output stream to render HTML content on the client.</param>
>> /// <param name="renderUpLevel">Indicates whether the client's browser
>> supports uplevel rendering.</param>
>> public void AddAttributesToRender(HtmlTextWriter writer, bool
>> renderUpLevel)
>> {
>> if (renderUpLevel)
>> {
>> string renderedControlID;
>> renderedControlID = DeriveId('_');
>>
>> writer.AddAttribute("controltochange", renderedControlID);
>> writer.AddAttribute("changecssclass", ChangeCssClass);
>> writer.AddAttribute("originalcssclass", this.originalCssClass);
>> }
>> }
>>
>>
>> Alessandro Zifiglio wrote:
>> > hi Jeremy, in your override of AddAttributesToRender, do not call
>> > base.AddAttributesToRender. Instead what you need to do is override
>> > this
>> > method as you are currently doing and add apply your customized
>> > attributes
>> > to it, which is probably being done via the method call to your helper
>> > class.
>> >
>> > Regards,
>> > Alessandro Zifiglio
>> > <jeremy.brews***@akqa.com> ha scritto nel messaggio
>> > news:1151058013.109033.231650@m73g2000cwd.googlegroups.com...
>> > > Hi Jim
>> > >
>> > > Thanks for the reply.  This is something we are already doing.  We
>> > > have
>> > > subclassed each validator for which we want to create a customised
>> > > behaviour.  So we have a class with the following definition:
>> > >
>> > > public class StyleChangingRequiredFieldValidator :
>> > > RequiredFieldValidator
>> > > {
>> > > private StyleChangingHelper helper;
>> > >
>> > > /// <summary>
>> > > /// Default constructor.
>> > > /// </summary>
>> > > public StyleChangingRequiredFieldValidator()
>> > > {
>> > > this.helper = new StyleChangingHelper(this);
>> > > }
>> > >
>> > > /// <summary>
>> > > /// The control whose style should be changed when validation results
>> > > in an invalid state.
>> > > /// </summary>
>> > > public string ControlToChange
>> > > {
>> > > get
>> > > {
>> > > return this.helper.ControlToChange;
>> > > }
>> > > set
>> > > {
>> > > this.helper.ControlToChange = value;
>> > > }
>> > > }
>> > >
>> > > /// <summary>
>> > > /// The CSS class to use when changing the style of the targeted
>> > > control.
>> > > /// </summary>
>> > > public string ChangeCssClass
>> > > {
>> > > get
>> > > {
>> > > return this.helper.ChangeCssClass;
>> > > }
>> > > set
>> > > {
>> > > this.helper.ChangeCssClass = value;
>> > > }
>> > > }
>> > >
>> > > /// <summary>
>> > > /// Raises the Init event.
>> > > /// </summary>
>> > > /// <param name="e">An EventArgs object that contains the event
>> > > data.</param>
>> > > protected override void OnInit(System.EventArgs e)
>> > > {
>> > > base.OnInit(e);
>> > > this.helper.OnInit(e);
>> > > }
>> > >
>> > > /// <summary>
>> > > /// Determines whether the value in the input control is valid.
>> > > /// </summary>
>> > > /// <returns><c>true</c> if the value in the input control is valid;
>> > > otherwise, <c>false</c>.</returns>
>> > > protected override bool EvaluateIsValid()
>> > > {
>> > > bool isValid = base.EvaluateIsValid();
>> > > return this.helper.EvaluateIsValid(isValid);
>> > > }
>> > >
>> > > /// <summary>
>> > > /// Raises the PreRender event.
>> > > /// </summary>
>> > > /// <param name="e">An EventArgs object that contains the event
>> > > data.</param>
>> > > protected override void OnPreRender(System.EventArgs e)
>> > > {
>> > > this.helper.OnPreRender(e);
>> > > base.OnPreRender(e);
>> > > }
>> > >
>> > > /// <summary>
>> > > /// Adds HTML attributes and styles that need to be rendered to the
>> > > specified System.Web.UI.HtmlTextWriter.
>> > > /// </summary>
>> > > /// <param name="writer">A System.Web.UI.HtmlTextWriter that
>> > > represents the output stream to render HTML content on the
>> > > client.</param>
>> > > protected override void AddAttributesToRender(HtmlTextWriter writer)
>> > > {
>> > > base.AddAttributesToRender(writer);
>> > > this.helper.AddAttributesToRender(writer, this.RenderUplevel);
>> > > }
>> > > }
>> > >
>> > > We have created a StyleChangingHelper class, an instance of which is
>> > > instantiated by each Validator derived subclass, and objects based on
>> > > this class handle the writing of the attributes.
>> > >
>> > > /// <summary>
>> > > /// Provides functionality for style changing validation controls.
>> > > /// </summary>
>> > > public class StyleChangingHelper
>> > > {
>> > > private BaseValidator validator;
>> > > private string controlToChange;
>> > > private string changeCssClass;
>> > > private object foundControl;
>> > > private string originalCssClass;
>> > > private const string evaluationFunctionSuffix = "_Verify";
>> > >
>> > > /// <summary>
>> > > /// Constructor which initialises the helper with a validator
>> > > instance.
>> > > /// </summary>
>> > > /// <param name="validator">The validator that this helper will be
>> > > helping.</param>
>> > > public StyleChangingHelper(BaseValidator validator)
>> > > {
>> > > this.validator = validator;
>> > > }
>> > >
>> > > /// <summary>
>> > > /// The control whose style should be changed when validation results
>> > > in an invalid state.
>> > > /// </summary>
>> > > public string ControlToChange
>> > > {
>> > > get
>> > > {
>> > > return this.controlToChange;
>> > > }
>> > > set
>> > > {
>> > > this.controlToChange = value;
>> > > }
>> > > }
>> > >
>> > > /// <summary>
>> > > /// The CSS class to use when changing the style of the targeted
>> > > control.
>> > > /// </summary>
>> > > public string ChangeCssClass
>> > > {
>> > > get
>> > > {
>> > > return this.changeCssClass;
>> > > }
>> > > set
>> > > {
>> > > this.changeCssClass = value;
>> > > }
>> > > }
>> > >
>> > > /// <summary>
>> > > /// Should be called by the base validator upon raising the Init
>> > > event.
>> > > /// </summary>
>> > > /// <param name="e">An EventArgs object that contains the event
>> > > data.</param>
>> > > public void OnInit(System.EventArgs e)
>> > > {
>> > >                               string controlID = DeriveId('$');
>> > >
>> > > this.foundControl = this.validator.Page.FindControl(controlID);
>> > > if (this.foundControl != null)
>> > > {
>> > > if (this.foundControl is WebControl)
>> > > {
>> > > WebControl foundWebControl = (WebControl) this.foundControl;
>> > > this.originalCssClass = foundWebControl.CssClass;
>> > > }
>> > > else if (foundControl is HtmlControl)
>> > > {
>> > > HtmlControl foundHtmlControl = (HtmlControl) this.foundControl;
>> > > this.originalCssClass = foundHtmlControl.Attributes["class"];
>> > > }
>> > > }
>> > > }
>> > >
>> > > /// <summary>
>> > > /// Determines whether the value in the input control is valid.
>> > > /// </summary>
>> > > /// <param name="isValid">Indicates whether the calling validator
>> > > considers the input control valid.</param>
>> > > public bool EvaluateIsValid(bool isValid)
>> > > {
>> > > if (!isValid)
>> > > {
>> > > if (this.foundControl != null)
>> > > {
>> > > if (this.foundControl is WebControl)
>> > > {
>> > > WebControl foundWebControl = (WebControl) this.foundControl;
>> > >
>> > > foundWebControl.CssClass = this.changeCssClass;
>> > > }
>> > > else if (foundControl is HtmlControl)
>> > > {

> hi Jeremy,
> so its just as Jim clearly stated in the previous post. In your place, i
> wont inherit the RequiredFieldValidator control. But write my own custom
> validator. The requiredFieldValidator control does not do much anyway, and
> there is minimum code for it. All the meat and postatoes of this controls
> code is just registering in the AddAttributesToRender method, only that
> un-needed expandoattribute that you want to exclude from your custom
> implementatoin, defining your own. Since you want to write a customized
> implementation, deriving from baseValidator is the way to go. Otherwise you
> have to deal with the obstacles you are dealing with  now and also for
> nothing.
>
> Good luck,
> Alessandro Zifiglio
>
> "JimOx" <Ji***@discussions.microsoft.com> ha scritto nel messaggio
> news:B3AD086D-DE1E-4DC2-97F8-6B37534C30B3@microsoft.com...
> > Jeremy,
> >
> > I believe that to do this you can go one of two ways.  Either don't call
> > the
> > base.AddAttributesToRender in your overriding method.  This will require
> > you
> > to have to manually register all of the attributes that the base class
> > would
> > have registered that you need.  The other option is to inherit from
> > BaseValidator instead of RequiredFieldValidator.  This is because
> > BaseValidator does not register the
> > "evaluationfunction" attribute but RequiredFieldValidator does and as far
> > as
> > I know once an ExpandoAttribute is registered there is no way to change
> > it's
> > value or remove the original.
> >
> > As a side note you will need to use
> > Page.ClientScript.RegisterExpandoAttribute to write the attribute instead
> > of
> > writer.AddAttribute.  This is because if you use writer.AddAttribute it
> > will
> > work in IE but not FireFox.  However
> > Page.ClientScript.RegisterExpandoAttribute will work in both.
> >
> > "jeremy.brews***@akqa.com" wrote:
> >
> >> Hi Alessando
> >>
> >> If I don't call the validator base.AddAttributesToRender then no aspect
> >> of the validator gets written to the page.
> >>
> >> As you say, I am overriding the AddAttributesToRender method in my
> >> custom validators and they do indeed call the StyleChangingHelper
> >> instance variable's method of the same name.
> >>
> >> MSDN states "Notes to Inheritors When overriding the
> >> AddAttributesToRender method, be sure to call the corresponding method
> >> in the base class. Otherwise, the attributes contained in the base
> >> class will not be rendered."
> >>
> >> Or are you suggesting that my override that does not call the base
> >> implementation needs to do more than it is doing at the minute?
> >>
> >> The StyleChangingRequiredFieldValidator has the following OnPreRender
> >> and AddAttributesToRender methods:
> >>
> >> /// <summary>
> >> /// Raises the PreRender event.
> >> /// </summary>
> >> /// <param name="e">An EventArgs object that contains the event
> >> data.</param>
> >> protected override void OnPreRender(System.EventArgs e)
> >> {
> >> this.helper.OnPreRender(e);
> >> base.OnPreRender(e);
> >> }
> >>
> >> /// <summary>
> >> /// Adds HTML attributes and styles that need to be rendered to the
> >> specified System.Web.UI.HtmlTextWriter.
> >> /// </summary>
> >> /// <param name="writer">A System.Web.UI.HtmlTextWriter that represents
> >> the output stream to render HTML content on the client.</param>
> >> protected override void AddAttributesToRender(HtmlTextWriter writer)
> >> {
> >> base.AddAttributesToRender(writer);
> >> this.helper.AddAttributesToRender(writer, this.RenderUplevel);
> >> }
> >>
> >> The StyleChangingHelper has the following custom methods of the same
> >> names:
> >>
> >> /// <summary>
> >> /// Should be called by the base validator upon raising the PreRender
> >> event.
> >> /// </summary>
> >> /// <param name="e">An EventArgs object that contains the event
> >> data.</param>
> >> public void OnPreRender(System.EventArgs e)
> >> {
> >> if (this.validator.EnableClientScript)
> >> {
> >> // this.validator.Attributes["evaluationfunction"] =
> >> this.validator.GetType().Name + evaluationFunctionSuffix;
> >> this.validator.Page.ClientScript.RegisterExpandoAttribute(validator.ClientID,
> >> "evaluationfunction", this.validator.GetType().Name +
> >> evaluationFunctionSuffix);
> >> }
> >> }
> >>
> >> /// <summary>
> >> /// Adds HTML attributes and styles that need to be rendered to the
> >> specified System.Web.UI.HtmlTextWriter.
> >> /// </summary>
> >> /// <param name="writer">A System.Web.UI.HtmlTextWriter that represents
> >> the output stream to render HTML content on the client.</param>
> >> /// <param name="renderUpLevel">Indicates whether the client's browser
> >> supports uplevel rendering.</param>
> >> public void AddAttributesToRender(HtmlTextWriter writer, bool
> >> renderUpLevel)
> >> {
> >> if (renderUpLevel)
> >> {
> >> string renderedControlID;
> >> renderedControlID = DeriveId('_');
> >>
> >> writer.AddAttribute("controltochange", renderedControlID);
> >> writer.AddAttribute("changecssclass", ChangeCssClass);
> >> writer.AddAttribute("originalcssclass", this.originalCssClass);
> >> }
> >> }
> >>
> >>
> >> Alessandro Zifiglio wrote:
> >> > hi Jeremy, in your override of AddAttributesToRender, do not call
> >> > base.AddAttributesToRender. Instead what you need to do is override
> >> > this
> >> > method as you are currently doing and add apply your customized
> >> > attributes
> >> > to it, which is probably being done via the method call to your helper
> >> > class.
> >> >
> >> > Regards,
> >> > Alessandro Zifiglio
> >> > <jeremy.brews***@akqa.com> ha scritto nel messaggio
> >> > news:1151058013.109033.231650@m73g2000cwd.googlegroups.com...
> >> > > Hi Jim
> >> > >
> >> > > Thanks for the reply.  This is something we are already doing.  We
> >> > > have
> >> > > subclassed each validator for which we want to create a customised
> >> > > behaviour.  So we have a class with the following definition:
> >> > >
> >> > > public class StyleChangingRequiredFieldValidator :
> >> > > RequiredFieldValidator
> >> > > {
> >> > > private StyleChangingHelper helper;
> >> > >
> >> > > /// <summary>
> >> > > /// Default constructor.
> >> > > /// </summary>
> >> > > public StyleChangingRequiredFieldValidator()
> >> > > {
> >> > > this.helper = new StyleChangingHelper(this);
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// The control whose style should be changed when validation results
> >> > > in an invalid state.
> >> > > /// </summary>
> >> > > public string ControlToChange
> >> > > {
> >> > > get
> >> > > {
> >> > > return this.helper.ControlToChange;
> >> > > }
> >> > > set
> >> > > {
> >> > > this.helper.ControlToChange = value;
> >> > > }
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// The CSS class to use when changing the style of the targeted
> >> > > control.
> >> > > /// </summary>
> >> > > public string ChangeCssClass
> >> > > {
> >> > > get
> >> > > {
> >> > > return this.helper.ChangeCssClass;
> >> > > }
> >> > > set
> >> > > {
> >> > > this.helper.ChangeCssClass = value;
> >> > > }
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// Raises the Init event.
> >> > > /// </summary>
> >> > > /// <param name="e">An EventArgs object that contains the event
> >> > > data.</param>
> >> > > protected override void OnInit(System.EventArgs e)
> >> > > {
> >> > > base.OnInit(e);
> >> > > this.helper.OnInit(e);
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// Determines whether the value in the input control is valid.
> >> > > /// </summary>
> >> > > /// <returns><c>true</c> if the value in the input control is valid;
> >> > > otherwise, <c>false</c>.</returns>
> >> > > protected override bool EvaluateIsValid()
> >> > > {
> >> > > bool isValid = base.EvaluateIsValid();
> >> > > return this.helper.EvaluateIsValid(isValid);
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// Raises the PreRender event.
> >> > > /// </summary>
> >> > > /// <param name="e">An EventArgs object that contains the event
> >> > > data.</param>
> >> > > protected override void OnPreRender(System.EventArgs e)
> >> > > {
> >> > > this.helper.OnPreRender(e);
> >> > > base.OnPreRender(e);
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// Adds HTML attributes and styles that need to be rendered to the
> >> > > specified System.Web.UI.HtmlTextWriter.
> >> > > /// </summary>
> >> > > /// <param name="writer">A System.Web.UI.HtmlTextWriter that
> >> > > represents the output stream to render HTML content on the
> >> > > client.</param>
> >> > > protected override void AddAttributesToRender(HtmlTextWriter writer)
> >> > > {
> >> > > base.AddAttributesToRender(writer);
> >> > > this.helper.AddAttributesToRender(writer, this.RenderUplevel);
> >> > > }
> >> > > }
> >> > >
> >> > > We have created a StyleChangingHelper class, an instance of which is
> >> > > instantiated by each Validator derived subclass, and objects based on
> >> > > this class handle the writing of the attributes.
> >> > >
> >> > > /// <summary>
> >> > > /// Provides functionality for style changing validation controls.
> >> > > /// </summary>
> >> > > public class StyleChangingHelper
> >> > > {
> >> > > private BaseValidator validator;
> >> > > private string controlToChange;
> >> > > private string changeCssClass;
> >> > > private object foundControl;
> >> > > private string originalCssClass;
> >> > > private const string evaluationFunctionSuffix = "_Verify";
> >> > >
> >> > > /// <summary>
> >> > > /// Constructor which initialises the helper with a validator
> >> > > instance.
> >> > > /// </summary>
> >> > > /// <param name="validator">The validator that this helper will be
> >> > > helping.</param>
> >> > > public StyleChangingHelper(BaseValidator validator)
> >> > > {
> >> > > this.validator = validator;
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// The control whose style should be changed when validation results
> >> > > in an invalid state.
> >> > > /// </summary>
> >> > > public string ControlToChange
> >> > > {
> >> > > get
> >> > > {
> >> > > return this.controlToChange;
> >> > > }
> >> > > set
> >> > > {
> >> > > this.controlToChange = value;
> >> > > }
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// The CSS class to use when changing the style of the targeted
> >> > > control.
> >> > > /// </summary>
> >> > > public string ChangeCssClass
> >> > > {
> >> > > get
> >> > > {
> >> > > return this.changeCssClass;
> >> > > }
> >> > > set
> >> > > {
> >> > > this.changeCssClass = value;
> >> > > }
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// Should be called by the base validator upon raising the Init
> >> > > event.
> >> > > /// </summary>
> >> > > /// <param name="e">An EventArgs object that contains the event
> >> > > data.</param>
> >> > > public void OnInit(System.EventArgs e)
> >> > > {
> >> > >                               string controlID = DeriveId('$');
> >> > >
> >> > > this.foundControl = this.validator.Page.FindControl(controlID);
> >> > > if (this.foundControl != null)
> >> > > {
> >> > > if (this.foundControl is WebControl)
> >> > > {
> >> > > WebControl foundWebControl = (WebControl) this.foundControl;
> >> > > this.originalCssClass = foundWebControl.CssClass;
> >> > > }
> >> > > else if (foundControl is HtmlControl)
> >> > > {
> >> > > HtmlControl foundHtmlControl = (HtmlControl) this.foundControl;
> >> > > this.originalCssClass = foundHtmlControl.Attributes["class"];
> >> > > }
> >> > > }
> >> > > }
> >> > >
> >> > > /// <summary>
> >> > > /// Determines whether the value in the input control is valid.
> >> > > /// </summary>
> >> > > /// <param name="isValid">Indicates whether the calling validator
> >> > > considers the input control valid.</param>
> >> > > public bool EvaluateIsValid(bool isValid)
> >> > > {
> >> > > if (!isValid)
> >> > > {
> >> > > if (this.foundControl != null)
> >> > > {
> >> > > if (this.foundControl is WebControl)
> >> > > {
> >> > > WebControl foundWebControl = (WebControl) this.foundControl;
> >> > >
> >> > > foundWebControl.CssClass = this.changeCssClass;
> >> > > }
> >> > > else if (foundControl is HtmlControl)
> >> > > {