在扩展asp.net Web控件时,应该在哪个事件中注入其他Web控件？

我试图通过扩展现有控件来避免复合控件或使用ASCX.但是,我无法将控件添加到继承的控件中并保持其视图状态/后置完整性.每当我在预渲染期间添加控件时,控件都会显示,但是post-back会抛出一个viewstate异常.我尝试在那里和LoadViewState期间添加它们(当然这是一个长镜头傻).我没有从我正在扩展的控件中获得Init.

The exception is
Sys.WebForms.PageRequestManagerServerErrorException:
Failed to load viewsstate. The control
tree into which viewstate is being
loaded must match the control tree
that was used to save viewstate during
the previous request. For example,
when adding controls dynamically,the
controls added during a post-back must
match the type and position of the
controls added during the initial
request

protected override void CreateChildControls(){
  Controls.Add(someControl);
  base.CreateChildControls();
}