通过示例看页面处理中的事件

来源：互联网发布：高薪网络销售招聘编辑：程序博客网时间：2024/05/01 21:27

这是一个用来演示ASP.NET页面处理过程时事件发挥的作用的示例，该示例通过动态（有点AJAX味道，但没有使用AJAX框架）的生成一张企业名片，讲述了几个常用事件的用法，更重要的是，里面的一些代码对于新手（比如当前的我）会很有帮助。

前台:EventDemo.aspx

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!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>Untitled Page</title>
</head>
<body style="font-size: 10pt; font-family: Arial">
    <form id="form1" runat="server">
    <div>
        <table style="width: 404px">
            <tr>
                <td style="width: 57px">
                    <asp:Label ID="NameLabel" runat="server" Text="Name:"></asp:Label></td>
                <td style="width: 238px">
                    <asp:TextBox ID="NameTextBox" runat="server" Width="146px" AutoPostBack="True" 
                        ontextchanged="NameTextBox_TextChanged"></asp:TextBox></td>
            </tr>
            <tr>
                <td style="width: 57px; height: 24px">
                    <asp:Label ID="TelNumLabel" runat="server" Text="Tel Num:"></asp:Label></td>
                <td style="width: 238px; height: 24px">
                    <asp:TextBox ID="TelNumTextBox" runat="server" Width="146px" 
                        AutoPostBack="True" ontextchanged="TelNumTextBox_TextChanged"></asp:TextBox></td>
            </tr>
            <tr>
                <td style="width: 57px; height: 24px;">
                    <asp:Label ID="RegionLabel" runat="server" Text="Region:"></asp:Label></td>
                <td style="width: 238px; height: 24px;">
                    <asp:DropDownList ID="RegionList" runat="server" Width="152px" 
                        AutoPostBack="True" 
                        onselectedindexchanged="RegionList_SelectedIndexChanged">
                    </asp:DropDownList></td>
            </tr>
            <tr>
                <td style="width: 57px; height: 24px">
                    <asp:Label ID="CountryLabel" runat="server" Text="Country:"></asp:Label></td>
                <td style="width: 238px; height: 24px">
                    <asp:DropDownList ID="CountryList" runat="server" Width="152px" 
                        AutoPostBack="True" 
                        onselectedindexchanged="CountryList_SelectedIndexChanged">
                    </asp:DropDownList></td>
            </tr>
        </table>
    
    </div>
        <asp:Button ID="UpdateButton" runat="server" Text="Update" />
        <br /><br />
        
        <asp:Panel ID="BusinessCardPanel" runat="server" Height="116px" Style="border-right: blue thin solid;
             padding-right: 3px; border-top: blue thin solid; padding-left: 3px; font-weight: bold;
             font-size: 14pt; padding-bottom: 3px; border-left: blue thin solid; color: navy;
             padding-top: 3px; border-bottom: blue thin solid; font-family: 'Century Gothic';
             background-color: lightblue" Width="660px">
           <asp:Label ID="BusinessCardNameLabel" runat="server"></asp:Label> <br /> <br />
           <asp:Label ID="BusinessCardTelNumLabel" runat="server"></asp:Label> <br /><br />
           <asp:Label ID="BusinessCardLocationLabel" runat="server"></asp:Label> 
            --<asp:Label ID="BusinessCardCountryLabel" runat="server"></asp:Label>
       </asp:Panel>
    </form>
</body>
</html>

后台EventDemo.aspx.cs

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.Collections.Generic;//使用Dictionary的必需 
public partial class _Default : System.Web.UI.Page 
{
    private Dictionary<string, ListItem[]> regionCountryData;//Dictionary 的用法，参看帮助; 
    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        regionCountryData = new Dictionary<string, ListItem[]>();
        regionCountryData["Americas"] = new ListItem[] { 
            new ListItem("USA"), 
            new ListItem("Canada"), 
            new ListItem("Brazil") 
        };
        regionCountryData["EMEA"] = new ListItem[] { 
            new ListItem("Switzerland"), 
            new ListItem("Dubai"), 
            new ListItem("Nigeria") 
        };
        
        regionCountryData["Asia Pacific"] = new ListItem[] { 
            new ListItem("India"), 
            new ListItem("Japan"), 
            new ListItem("Australia") 
        };
    }
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            RegionList.Items.Add("---Please select---");
            foreach (string region in regionCountryData.Keys)
            {
                RegionList.Items.Add(region);
            }
            CountryList.Items.Add("---Please select---");
        }
    }
    protected void RegionList_SelectedIndexChanged(object sender, EventArgs e)
    {
        string region = RegionList.SelectedValue;
        BusinessCardLocationLabel.Text = region;
        CountryList.Items.Clear();
        CountryList.Items.Add("---Please select---");
        CountryList.Items.AddRange(regionCountryData[region]);
    }
    protected void CountryList_SelectedIndexChanged(object sender, EventArgs e)
    {
        BusinessCardCountryLabel.Text = CountryList.SelectedItem.ToString();
    }
    protected void NameTextBox_TextChanged(object sender, EventArgs e)
    {
        BusinessCardNameLabel.Text = NameTextBox.Text;
    }
    protected void TelNumTextBox_TextChanged(object sender, EventArgs e)
    {
        BusinessCardTelNumLabel.Text = TelNumTextBox.Text;
    }
   
}

该示例来源于 TotalTraning 的讲座