I ran the solution in VS and then opened TestCallingTestWebDialogControl.aspx in Script Documents/Windows Internet Explorer

 Looks like it might be "incTestWebDialog_confirmDelete_clientState"

 <input type="hidden" id="incTestWebDialog_confirmDelete_clientState" name="incTestWebDialog_confirmDelete_clientState" /><div class="ig_Control igdw_Control :=CtlMain:layout" id="incTestWebDialog_confirmDelete" style="height:300px;width:400px;overflow:hidden;position:absolute;display:none;visibility:hidden;">

 I also saw the following script:

     <script type="text/javascript">
//<![CDATA[
Sys.WebForms.PageRequestManager._initialize('incTestWebDialog$ScriptManager1', document.getElementById('aspnetForm'));
Sys.WebForms.PageRequestManager.getInstance()._updateControls([, [, [, 90);
//]]>
</script>
 

I then get an error "'null' is null or not an object" when I click on:

 <input type="button" value="Show (Client Side)" onclick="$find('confirmDelete').show();" />

Based on what you said, I tried adding a watch for $find("incTestWebDialog_confirmDelete_clientState") and $find("incTestWebDialog$ScriptManager1") and they were both null also.

 -Eric

 Rumen,

 I wasn't able to get this syntax to work. My .ascx code looks like:

<form id="frmMyForm" runat=server>
            <asp:ScriptManager ID="ScriptManager1" runat="server" />
            <cc1:WebDialogWindow ID="confirmDelete" runat="server" Height="300px" Width="400px"
                    WindowState="Hidden" Modal="True">
                    <ContentPane>
                        <Template>
                        <asp:Label ID="deleteMessage" runat="server" Text="Label"></asp:Label>
                        </Template>
                    </ContentPane>
            </cc1:WebDialogWindow>
</form>

I've set a breakpoint in my javascript and have tried various versions of the $find method in the immediate pane:

$find('<%= deleteMessage %>')
$find('<%= confirmDelete %>')
$find('<%= deleteMessage.confirmDelete %>')
$find('<%= frmMyForm.deleteMessage.confirmDelete %>')
$find('<%= confirmDelete.ClientID %>')

They all return null. 

 The only way I get get a value is the confirmDelete webdialog is by:

$find('incAttachments1_confirmDelete')

This is the name of the control from doing a view source.

 -Eric

The general problem is that ASP.NET AJAX expects the client-side ID of the control and in the case of nested controls inside Templates (or in fact, any other INamingContainer), so you can use the following syntax instead of hardcoding the client id (there is not guarantee that the ID will be the same if you add other controls on the page)

e.g.

$find('<%= confirmDelete.ClientID %>').

Hello,

I looked a little further down the page and saw:

 <script type="text/javascript">
//<![CDATA[
Sys.Application.initialize();
Sys.Application.add_init(function() {
    $create(Infragistics.Web.UI.WebDialogWindow, {"id":"incTestWebDialog_confirmDelete","name":"confirmDelete","props":[[[,3,,,"400px","300px",,,,1,,0],{"c":{"uid":"incTestWebDialog$confirmDelete","buts":"7igdw_ModalBackground","mbc":"igdw_ModalBackground"}}],[[[[,,,]],[[[[,{"c":{"s":"i","a":"Close","h":"/ig_res/Default/images/igdw_CloseHover.gif","i":"/ig_res/Default/images/igdw_Close.gif","p":"/ig_res/Default/images/igdw_CloseMouseDown.gif"}}],,],[[[],,],[[[],,]],],[[[,,,,]],,]],,[]}, null, null, $get("incTestWebDialog_confirmDelete"));
});
//]]>
</script>

So on TestWebDialog.ascx I changed my input button to:

<input type="button" value="Show (Client Side)" onclick="$find('incTestWebDialog_confirmDelete').show();" />

and it worked!

Thanks,

Eric