在其他自定义控件中加载WebControl：从不触发Load方法

Question

I have a simple class inheriting from WebControl as follow:

public class Instrument : WebControl
{
    private SpecialItem myItem = new SpecialItem("ABC");

    protected override void Render(HtmlTextWriter output)
    {
       output.Write("<div>");
       myItem.RenderControl(output);
       output.Write("</div>");
    }
}

Once the control is added to a web page, the SpecialItem gets displayed but its inner "Load" method is never fired which makes it unusable. If I use the SpecialItem control on its own then it works as expected. How do you I make the load method from the SpecialItem control get executed?

Answer 1

Add myItem to the Controls collection of your custom control. You typically do this (as well as instantiating the child controls) by overriding the method CreateChildControls :

protected override void CreateChildControls()
{
    myItem = new SpecialItem("ABC");
    Controls.Add(myItem);
}