今天学习母版的时候遇到一件很怪的事情,就是不能触发DropDownList1_SelectedIndexChanged(object sender, EventArgs e)事件,检查了很久发现代码没有错误,于是在一个新的页面里拖放了一个Label控件和一个DropDownList控件,当触发DropDownList1_SelectedIndexChanged(object sender, EventArgs e)事件的时候把值传给Label的text属性来检查是否能触发DropDownList1_SelectedIndexChanged(object sender, EventArgs e)事件,但运行后无论如何选择DropDownList控件的值,Label的text都没有变,怪怪怪啊!!!!
代码如下:
Default.aspx
Default.aspx.cs
代码如下:
Default.aspx
1
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
2
3<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
4
5<html xmlns="http://www.w3.org/1999/xhtml" >
6<head runat="server">
7 <title>Untitled Page</title>
8</head>
9<body>
10 <form id="form1" runat="server">
11 <div>
12 <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
13 <asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
14 <asp:ListItem>123</asp:ListItem>
15 <asp:ListItem>456</asp:ListItem>
16 <asp:ListItem>789</asp:ListItem>
17 <asp:ListItem>abc</asp:ListItem>
18 </asp:DropDownList>
19 </div>
20 </form>
21</body>
22</html>
23
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>2
3
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">4
5
<html xmlns="http://www.w3.org/1999/xhtml" >6
<head runat="server">7
<title>Untitled Page</title>8
</head>9
<body>10
<form id="form1" runat="server">11
<div>12
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>13
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">14
<asp:ListItem>123</asp:ListItem>15
<asp:ListItem>456</asp:ListItem>16
<asp:ListItem>789</asp:ListItem>17
<asp:ListItem>abc</asp:ListItem>18
</asp:DropDownList>19
</div>20
</form>21
</body>22
</html>23
Default.aspx.cs
1using System;
2using System.Data;
3using System.Configuration;
4using System.Web;
5using System.Web.Security;
6using System.Web.UI;
7using System.Web.UI.WebControls;
8using System.Web.UI.WebControls.WebParts;
9using System.Web.UI.HtmlControls;
10
11public partial class _Default : System.Web.UI.Page
12
{
13
protected void Page_Load(object sender, EventArgs e)
14
{
15
16
}
17 protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
18 {
19 Label1.Text = DropDownList1.SelectedValue;
20 }
21
}
22
using System;2
using System.Data;3
using System.Configuration;4
using System.Web;5
using System.Web.Security;6
using System.Web.UI;7
using System.Web.UI.WebControls;8
using System.Web.UI.WebControls.WebParts;9
using System.Web.UI.HtmlControls;10
11
public partial class _Default : System.Web.UI.Page 12
{
13
protected void Page_Load(object sender, EventArgs e)14
{
15
16
}17
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)18
{19
Label1.Text = DropDownList1.SelectedValue;20
}21
}22
