1. <asp:RadioButton ID="male" runat="server" AutoPostBack="True"  GroupName="sex"                                                        oncheckedchanged="male_CheckedChanged" Text="男" />  
2. <asp:RadioButton ID="female" runat="server" AutoPostBack="True"  GroupName="sex"                                                      oncheckedchanged="female_CheckedChanged" Text="女" />  
3.   
4.   
5.    protected void male_CheckedChanged(object sender, EventArgs e)  
6.         {  
7.             if (male.Checked == true)  
8.             {  
9.                 Response.Write("男人自當(dāng)頂天立地！");  
10.             }  
11.   
12.         }  
13.         protected void female_CheckedChanged(object sender, EventArgs e)  
14.         {  
15.             if (female.Checked == true)  
16.             {  
17.                 Response.Write("巾幗不會(huì)讓須眉！");  
18.             }  
19.         }  

<asp:RadioButton ID="male" runat="server" AutoPostBack="True"  GroupName="sex"                                                        oncheckedchanged="male_CheckedChanged" Text="男" />
<asp:RadioButton ID="female" runat="server" AutoPostBack="True"  GroupName="sex"                                                      oncheckedchanged="female_CheckedChanged" Text="女" />


   protected void male_CheckedChanged(object sender, EventArgs e)
        {
            if (male.Checked == true)
            {
                Response.Write("男人自當(dāng)頂天立地！");
            }

        }
        protected void female_CheckedChanged(object sender, EventArgs e)
        {
            if (female.Checked == true)
            {
                Response.Write("巾幗不會(huì)讓須眉！");
            }
        }

在上面的定義中，GroupName必須設(shè)置相同屬性，在這里，設(shè)置為同一字段，否則無法識(shí)別是否為單選。