using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.ComponentModel;

[assembly: TagPrefix("TestTemplate.Controls", "Container")]
namespace TestTemplate.Controls
{
    public abstract class BaseControlContainer:PlaceHolder
    {
        public override Control FindControl(string id)
        {
            Control ctrl = base.FindControl(id);
            if (ctrl == null && this.Controls.Count == 1)
            {
                ctrl = this.Controls[0].FindControl(id);
            }
            return ctrl;
        }

private string _SkineName = "UserControls/Test.ascx";

[Category("皮肤设置")]
        [Description("皮肤名称")]
        public string SkineName
        {
            get { return _SkineName;}
            set { _SkineName = value; }
        }

protected override void OnLoad(EventArgs e)
        {
            Page = HttpContext.Current.Handler as System.Web.UI.Page;//获取当前上下文的Page
            this.Controls.Add(Page.LoadControl(_SkineName));//装载ascx控件
            AttachChildControls();
            DataHandle();
        }
        protected abstract void AttachChildControls();//附加控件

protected abstract void DataHandle();//数据处理

}
}

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

namespace TestTemplate.Controls
{
    public class TestControl:BaseControlContainer
    {
        TextBox Textbox1;

protected override void AttachChildControls()
        {
     //在这里查找ascx页面上的控件
            Textbox1 = FindControl("textbox1") as TextBox; 
        }

protected override void DataHandle()
        {
     //这里对页面控件进行数据处理
            Textbox1.Text = "OK";
        }
    }
}