Checkbox state after postback

13 Feb 2006 4:24 PM

Oxns

Hi,

I have a pge on which is a placeholder. I fill the placeholder at runtime
with a number of dynamically created controls. Most of these work just fine,
except my checkbox.

When I first load the page the chekbox displays correctly either checked or
not.

After a postback however (the controls are all rebuilt) IF the checkbox was
checked before postback - it is checked again after postback - which is
fine. BUT if the checkbox was NOT checked - after the postback it shows up
as checked.

I have debugged the code and it is definitely 'Checked = False - even after
adding to the placeholder.

What I see on the page is a new attribute : checked="checked".

NB I even tried forcing the output of an attribute : checked="false" - which
is ALSO output but has no effect.

I have tried placeholder1.controls.clear().

I have tried Viewstete.clear()

No effect.

Anyone got an idea ????.

NB The actual controls are in a module on a DotNetNuke page :-O. Module
written in C#.

CheckBox ck = new CheckBox();

ck.EnableViewState = true;

ck.Checked = false;

if (Convert.ToBoolean(ds.Tables[tablename].Rows[0][ctl.field].ToString()))

{

ck.Checked = true;

ck.Enabled = true;

ck.InputAttributes.Add("checked", "true");

}

else

{

ck.Checked = false;

ck.Enabled = true;

ck.Attributes.Remove("checked");

// ck.InputAttributes.Add("checked", "false");

}

//ck.ID = ctl.name;

ck.TextAlign = TextAlign.Left;

ck.Text = ctl.text;

ck.CssClass = ctl.cssclass;

ph.Controls.Add(ck);

Thanks - hopefully

Graham

13 Feb 2006 4:36 PM

Oxns

Actually - I stated the case a little incorrectly. The checkbox state is
controlled by a database lookup. If it was checked on the page, but when
read from the database should be unchecked, this is when it goes wrong.

IE Checked on the page. Database says should be unchecked, so set up as
unchecked when creating the checkbox, but it still displays on the page as
checked. Thus once its been shown as checked on the page, no matter how it
is recreated it shows as checked, until I refresh the whole page from
scratch :-O.

Show quoteHide quote

"Oxns" <oxns@community.nospam> wrote in message
news:u32sAoLMGHA.1760@TK2MSFTNGP10.phx.gbl...
> Hi,
>
> I have a pge on which is a placeholder. I fill the placeholder at runtime
> with a number of dynamically created controls. Most of these work just
> fine, except my checkbox.
>
> When I first load the page the chekbox displays correctly either checked
> or not.
>
> After a postback however (the controls are all rebuilt) IF the checkbox
> was checked before postback - it is checked again after postback - which
> is fine. BUT if the checkbox was NOT checked - after the postback it shows
> up as checked.
>
> I have debugged the code and it is definitely 'Checked = False - even
> after adding to the placeholder.
>
> What I see on the page is a new attribute : checked="checked".
>
> NB I even tried forcing the output of an attribute : checked="false" -
> which is ALSO output but has no effect.
>
> I have tried placeholder1.controls.clear().
>
> I have tried Viewstete.clear()
>
> No effect.
>
> Anyone got an idea ????.
>
> NB The actual controls are in a module on a DotNetNuke page :-O. Module
> written in C#.
>
> CheckBox ck = new CheckBox();
>
> ck.EnableViewState = true;
>
> ck.Checked = false;
>
> if (Convert.ToBoolean(ds.Tables[tablename].Rows[0][ctl.field].ToString()))
>
> {
>
> ck.Checked = true;
>
> ck.Enabled = true;
>
> ck.InputAttributes.Add("checked", "true");
>
> }
>
> else
>
> {
>
> ck.Checked = false;
>
> ck.Enabled = true;
>
> ck.Attributes.Remove("checked");
>
> // ck.InputAttributes.Add("checked", "false");
>
> }
>
> //ck.ID = ctl.name;
>
> ck.TextAlign = TextAlign.Left;
>
> ck.Text = ctl.text;
>
> ck.CssClass = ctl.cssclass;
>
> ph.Controls.Add(ck);
>
>
> Thanks - hopefully
>
> Graham
>
>

14 Feb 2006 2:52 AM

Steven Cheng[MSFT]

Hi Graham,

Welcome to the ASP.NET newsgroup.

As for the dynamically created webcontrols, we should always create and add
them into the container control in page's init or load event(init is
prefered). After the control is added into container control in page, if it
is during postback, the control will try restore its state from ViewState.
Therefore, we should not set any state onto dynamic created controls before
they're added into container control. Also, for your scenario, I suggest
you consider adding the dynamic controls in page init event and do other
data binding or load operations in Page_load, e.g:

=========(this is an ASP.NET 2.0 page)=========
public partial class DynaControlPage : System.Web.UI.Page
{
    private CheckBox _chk;

    protected void Page_Init(object sender, EventArgs e)
    {
        _chk = new CheckBox();
        _chk.ID = "chkDynamic";
        _chk.Text = "Dynamic CheckBox";

        ph1.Controls.Add(_chk);
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        _chk.Checked = CheckBox1.Checked;

    }

}
==============

In addition , here is a kb article describing dynamically creating
webcontrol on page:

#HOW TO: Dynamically Create Controls in ASP.NET by Using Visual C# .NET
http://support.microsoft.com/kb/317794/en-us

Hope this helps.

Regards,

Steven Cheng
Microsoft Online Support

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