HowTo: Control the rendered Html tag on your custom, composite server controls

Normally when you want to achieve that your custom server control is rendered inside a specific HTML tag you don't override the Render method, but you do something like

public class MySrvControl : WebControl, INamingContainer
{
   public MySrvControl() : base(HtmlTextWriterTag.Div)
   {
      ...
   }

   ...

}

Now most often you'll probably have a composite control, meaning that you are aggregating a couple of already existing controls inside your custom server control, providing some further functionality. In such a case, the .Net framework provides the CompositeControl class which should be inherited in that case:

public class MySrvControl : CompositeControl
{
   public MySrvControl() : base(HtmlTextWriterTag.Div)
   {
      ...
   }

   ...

}

Note, you don't need the INamingContainer marker interface any more, because it's already done by the CompositeControl. The line "base(HtmlTextWriterTag.Div) however will give you a compiler error, since there is no constructor on the CompositeControl which is taking parameters. So to still provide the same rendering functionality, you simply add

public class MySrvControl : CompositeControl
{
   public MySrvControl()
   {
      ...
   }

   protected override HtmlTextWriterTag TagKey
   {
      get
      {
         return HtmlTextWriterTag.Div;
      }
   }

   ...

}

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