I'm trying to encapsulate the text box watermark into my own textbox control.  My textbox control overrides the built-in textbox and adds various functions such as validators, etc.  I've given it a property of WatermarkText, and when that property is used, I want to apply the watermark.

I've been using the following code in my textbox control:

protected override void CreateChildControls()
        {
            if (!string.IsNullOrEmpty(this.WatermarkText) && Microsoft.Web.UI.ScriptManager.GetCurrent(this.Page) != null)
            {
                this.Controls.Clear();

                AtlasControlToolkit.TextBoxWatermarkExtender te = new AtlasControlToolkit.TextBoxWatermarkExtender();

                watermarkProperties.TargetControlID = this.ID;

                if (string.IsNullOrEmpty(watermarkProperties.WatermarkCssClass))
                    watermarkProperties.WatermarkCssClass = "TextBoxWatermark";

                te.TargetProperties.Add(watermarkProperties);
                Controls.Add(te);
            }
        }

This has been working fine on simple pages.  But in the following scenario, it does not work:

Page -> multiview -> user control.  So, either when it's part of a multiview, or usercontrol, it does not work.  I get javascript errors.

Any ideas what to do?  Or is this just a bug?  Should I be using Controls.Add on the last line, or should I use:

Microsoft.Web.UI.ScriptManager.GetCurrent(Page).Controls.Add(te);

Both work on the regular page, but not on my more complex page.


Thanks!

Your Add call should add the extender in the same naming scope as it's target.  But in the example above, what is the parent control?  A Textbox or another control that contains a textbox and the extender? 

In any case, what are the Javascript errors you're seeing?

the parent control is a textbox that inherits from the asp.net textbox.

When i use Microsoft.Web.UI.ScriptManager.GetCurrent(Page).Controls.Add(te);...i get the following javascript error:

Target control with ID "TextBoxName" could not be found for extender.

Again, when i put it on a simple page, it works beautifully.  But in the scenario of Page -> multiview -> user control, i get that error.

But I think there's an issue in general with this extender and user controls, or multiviews, because even if I put the extended into the markup it still does the same thing.

The issue here is that the extender can't find the target.  Internally the extender does (basically):

NamingContainer.FindControl(TargetControlID);

If that comes back null, you'll get the error you're seeing.  Go ahead and paste in your markup-only repro and maybe I can spot the issue.