ASP.NET WebControl and rendering contained children

Question

Hey all.

I'm looking to create a WebControl that can house markup inside it, and do its own dynamic creation of child controls. The issue I'm having is that I can't (yet) render the controls housed in the markup (see example below) separate from the child controls I create.

I'm aware I need to set up the class with these 2 flags:

[ParseChildren(false)]
[PersistChildren(true)]
public class OuterControl : WebControl
{
  ...
}

And sample markup would look like:

<custom:OuterControl>
  <asp:TextBox ...>
<custom:OuterControl>

Inside RenderContents(), I have some controls I need to add to the control tree, render, then render the ones wrapped in markup in a particular part. E.g.:

protected override void RenderContents(HtmlTextWriter output)
{
  EnsureChildControls();
  [ Misc work, render my controls ]

  [** Would like to render wrapped children here **]

  [ Possibly other misc work ]
}

As stated, I can either get my code-created controls to render twice from calling RenderChildren(), or the wrapped controls to not render at all by removing that line. Darn.

Thoughts?

Answer 1

When I had a similar requirement (building a standard set of controls around the controls supplied), I ended up doing something like this:

EnsureChildControls();

Control[] currentControls = new Control[Controls.Count];

if (HasControls()) {
  Controls.CopyTo(currentControls, 0);
  Controls.Clear();
}

// Misc work, add my controls, etc, e.g.
Panel contentBox = new Panel { ID = "Content", CssClass = "content_border" };
// at some point, add wrapped controls to a control collection
foreach (Control currentControl in currentControls) {
  contentBox.Controls.Add(currentControl);
}

// Finally, add new controls back into Control collection
Controls.Add(contentBox);

Which has held up quite well.