原文发布时间为：2008-07-30 —— 来源于本人的百度文章 [由搬家工具导入]

Web用户控件test.ascx的源代码：

using System;
using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;

public partial class test : System.Web.UI.UserControl
{
    private string myname;
    private int n;

    public string Myname
    {
        get { return myname; }
        set { myname = value; }
    }
    public int N
    {
        get { return n; }
        set { n = value; }
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            Label1.Text = myname;
            for (int i = 0; i < n; i++)
            {
                ListBox1.Items.Add(i.ToString());
            }
        }
    }
}

----------------------------

这时你可以看见它多了Myname与N这两个属性，你可以右击控件，属性，然后进行更改，还可以动态加载，代码如下：
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;

public partial class _Default : System.Web.UI.Page
{
    private ASP.test_ascx t;//页面上必须有一个test这样的控件时，才能有ASP.test_ascx类型
   
    protected void Page_Load(object sender, EventArgs e)
    {
        Test1.Visible = false;//要动态添加，首先页面上必须有一个这样的控件，所以拉一个，然后不让它显示即可
        t = (ASP.test_ascx)LoadControl("~/test.ascx");
        t.Myname = "dongtai";
        t.N = 3;
        PlaceHolder1.Controls.Add(t);
    }
}