给WEB用户控件添加事件

在创建某个用户控件时，我使用了TextBox控件，我想用户控件也有TextChanged这样的事件，怎么实现呢？下面提供了一种方法。

阅读本部分内容需要具备【委托（delegate）和事件（event）】的相关知识。实际上，代码非常简单。

1、创建用户控件

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="UserTextBox.ascx.cs" Inherits="UserTextBox" %>
<asp:TextBox ID="txtUserTextBox" runat="server"
ontextchanged="txtUserTextBox_TextChanged"></asp:TextBox>

using System;

public partial class UserTextBox : System.Web.UI.UserControl
{
    #region private fields
    private string _Text;
    #endregion

    public delegate void TextChangedHandler(object sender, TextChangedEventArgs e);
    public event TextChangedHandler TextChanged;

    public void OnTextChaged(TextChangedEventArgs e)
    {
        if (TextChanged != null)
        {
            TextChanged(this, e);
        }
    }
    //在这里触发事件
    protected void txtUserTextBox_TextChanged(object sender, EventArgs e)
    {
        OnTextChaged(new TextChangedEventArgs(txtUserTextBox.Text));
    }
    /// <summary>
    /// 事件数据类
    /// </summary>
    public class TextChangedEventArgs : EventArgs
    {
        public readonly string Text;
        public TextChangedEventArgs(string Text)
        {
            this.Text = Text;
        }
    }

    #region Properties
    public bool AutoPostBack
    {
        get
        {
            return txtUserTextBox.AutoPostBack;
        }
        set
        {
            txtUserTextBox.AutoPostBack = value;
        }
    }
    public string Text
    {
        get { return _Text; }
        set { _Text = value; }
    }
    #endregion
}

2、使用ASP.NET窗体测试

注意：事件不能在属性窗口点击“闪电”符号那里添加，而是在窗体类中写代码添加的，这里是重写了基类Page中的OnInit方法。

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register src="UserTextBox.ascx" tagname="UserTextBox" tagprefix="uc1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

        <uc1:UserTextBox ID="UserTextBox1" runat="server"
            AutoPostBack="True"/>

    </div>
    </form>
</body>
</html>

using System;

public partial class _Default : System.Web.UI.Page
{

    void UserTextBox1_TextChanged(object sender, UserTextBox.TextChangedEventArgs e)
    {
        Response.Write(e.Text);
    }

    protected override void OnInit(EventArgs e)
    {
        this.UserTextBox1.TextChanged += new UserTextBox.TextChangedHandler(UserTextBox1_TextChanged);
        base.OnInit(e);
    }
}