DropDownList select: first visible a label, then post back

11 Mar 2006 7:08 PM

David Thielen

Hi;

When a DropDownList item is selected, I want to first make a hidden label
visible, then have it post back. The label says "processing..." by the list
and will be hidden again when the page is returned in 2 - 4 seconds.

How can I do this?

--
thanks - dave
david_at_windward_dot_net
http://www.windwardreports.com

11 Mar 2006 7:46 PM

Phillip Williams

You might program the onchange event of the <select> tag that is rendered by
the <asp:DropDownList> control to execute a JavaScript that turns a <span>
visible and causes a hidden button click event that would post back to the
server instead of having the DropDownList postback set to true.

--
HTH,
Phillip Williams
http://www.societopia.net
http://www.webswapp.com

Show quoteHide quote

"David Thielen" wrote:

> Hi;
>
> When a DropDownList item is selected, I want to first make a hidden label
> visible, then have it post back. The label says "processing..." by the list
> and will be hidden again when the page is returned in 2 - 4 seconds.
>
> How can I do this?
>
> --
> thanks - dave
> david_at_windward_dot_net
> http://www.windwardreports.com
>

11 Mar 2006 9:20 PM

David Thielen

Hi;

I just tried this but I think I'm doing something wrong. Does anyone have a
javascript function that does this or knows of a url showing it?

--
thanks - dave
david_at_windward_dot_net
http://www.windwardreports.com

Show quoteHide quote

"Phillip Williams" wrote:

> You might program the onchange event of the <select> tag that is rendered by
> the <asp:DropDownList> control to execute a JavaScript that turns a <span>
> visible and causes a hidden button click event that would post back to the
> server instead of having the DropDownList postback set to true.
>
> --
> HTH,
> Phillip Williams
> http://www.societopia.net
> http://www.webswapp.com
>
>
> "David Thielen" wrote:
>
> > Hi;
> >
> > When a DropDownList item is selected, I want to first make a hidden label
> > visible, then have it post back. The label says "processing..." by the list
> > and will be hidden again when the page is returned in 2 - 4 seconds.
> >
> > How can I do this?
> >
> > --
> > thanks - dave
> > david_at_windward_dot_net
> > http://www.windwardreports.com
> >

11 Mar 2006 11:37 PM

Phillip Williams

It is not going to be one simple script. It might take an hour to patch
together a few of them, so I will leave you with links and you have to do the
hour's work.

1) onchange event: http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/reference/events/onchange.asp

2) save the clientID of the label control to the browser javascript during
the PreRender event like I did in this sample: http://www.webswapp.com/codesamples/viewsource.aspx?file=~/codesamples/aspnet20/textbox/default.aspx

3) create a button and style with cssClass="Hidden" where Hidden is defined
as display = "none"

4) at the end of your javascript call the Click method of the Button (you
need the ClientID of the button to be sent in step#2

5) Program the Button click event to do the equivalent of what the
dropdownlist selectedIndexChanged would have done.

--
HTH,
Phillip Williams
http://www.societopia.net
http://www.webswapp.com

Show quoteHide quote

"David Thielen" wrote:

> Hi;
>
> I just tried this but I think I'm doing something wrong. Does anyone have a
> javascript function that does this or knows of a url showing it?
>
> --
> thanks - dave
> david_at_windward_dot_net
> http://www.windwardreports.com
>
>
>
> "Phillip Williams" wrote:
>
> > You might program the onchange event of the <select> tag that is rendered by
> > the <asp:DropDownList> control to execute a JavaScript that turns a <span>
> > visible and causes a hidden button click event that would post back to the
> > server instead of having the DropDownList postback set to true.
> >
> > --
> > HTH,
> > Phillip Williams
> > http://www.societopia.net
> > http://www.webswapp.com
> >
> >
> > "David Thielen" wrote:
> >
> > > Hi;
> > >
> > > When a DropDownList item is selected, I want to first make a hidden label
> > > visible, then have it post back. The label says "processing..." by the list
> > > and will be hidden again when the page is returned in 2 - 4 seconds.
> > >
> > > How can I do this?
> > >
> > > --
> > > thanks - dave
> > > david_at_windward_dot_net
> > > http://www.windwardreports.com
> > >

13 Mar 2006 5:10 AM

Steven Cheng[MSFT]

Hi Dave,

I agree with Phillip that you can register the client-side "onchange" event
handler for the dropdownlist control. Also(you can also consider the
<form>'s "onsubmit" event I mentioned in your former thread). Here is a
simple test page which register a client-side "onchange" script handler for
the dropdownlist to display a hidden html <div>:

=========aspx template =============
.......................
<script language="javascript">
        function before_postback()
        {
            document.getElementById("divWait").style.display = "";
        }
        </script>
    </HEAD>
    <body>
        <form id="Form1" method="post" runat="server">
            <table width="100%">
                <tr>
                    <td>
                        <div id="divWait" style="DISPLAY:none">The data is being processed,
please
                            wait.................</div>
                    </td>
                </tr>
                <tr>
                    <td style="HEIGHT: 19px">
                        <asp:DropDownList id="lstItems" runat="server" AutoPostBack="True">
                            <asp:ListItem Value="aaa">aaa</asp:ListItem>
                            <asp:ListItem Value="bbb">bbb</asp:ListItem>
                            <asp:ListItem Value="ccc">ccc</asp:ListItem>
                            <asp:ListItem Value="ddd">ddd</asp:ListItem>
                        </asp:DropDownList>
                    </td>
                </tr>
........................
===============================

=======code behind=============

private void Page_Load(object sender, System.EventArgs e)
        {
            // Put user code to initialize the page here
            lstItems.Attributes["onchange"] = "before_postback();";
        }

private void lstItems_SelectedIndexChanged(object sender, System.EventArgs
e)
        {
            System.Threading.Thread.Sleep(5000);

            Response.Write("<br/>SelectedIndexChanged....");
        }
========================

Hope this also helps.

Regards,

Steven Cheng
Microsoft Online Support

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