private void Button1_Click(object sender, System.EventArgs e)
{

if (Page.IsValid)
{
Label1.Text="比较正确";

}
else
Label1.Text="比较不正确";

}

private void ListBox1_SelectedIndexChanged(object sender, System.EventArgs e)
{
CompareValidator1.Operator=ListBox1.SelectedIndex;

CompareValidator1.Validate();
}
这个是我的代码 可是运行的时候出现"无法将类型隐式的转化为system.web.ui.webcontril.validationcompareoperator" 问下下该怎么办 在线

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace WebAp
{
/// <summary>
/// WebForm2 的摘要说明。
/// </summary>
public class WebForm2 : System.Web.UI.Page
{
protected System.Web.UI.WebControls.TextBox TextBox1;
protected System.Web.UI.WebControls.ListBox ListBox1;
protected System.Web.UI.WebControls.TextBox TextBox2;
protected System.Web.UI.WebControls.Button Button1;
protected System.Web.UI.WebControls.Label Label1;
protected System.Web.UI.WebControls.CompareValidator CompareValidator1;

private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
}

#region Web 窗体设计器生成的代码
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
//
InitializeComponent();
base.OnInit(e);
}

/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.ListBox1.SelectedIndexChanged += new System.EventHandler(this.ListBox1_SelectedIndexChanged);
this.Button1.Click += new System.EventHandler(this.Button1_Click);
this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

private void Button1_Click(object sender, System.EventArgs e)
{

if (Page.IsValid)
{
Label1.Text="比较正确";

}
else
Label1.Text="比较不正确";

}

private void ListBox1_SelectedIndexChanged(object sender, System.EventArgs e)
{
CompareValidator1.Operator=(ValidationCompareOperator)ListBox1.SelectedIndex;

CompareValidator1.Validate();
}
}
}
改过后没有报错 但是没有体现出效果啊!请在帮我看看!谢谢!

CompareValidator1.Operator=(ValidationCompareOperator)ListBox1.SelectedIndex;
里面的有先后顺序!!操作符号