服务器控件的几个属性 SelectedIndex、SelectedItem、SelectedValue、SelectedItem.Text、selectedItem.value

转自http://blog.csdn.net/iqv520/article/details/4419186

1. SelectedIndex ——选项的索引，为int，从0开始，可读可写

2. SelectedItem ——选择项，是一个对象，为ListItem，只读不写

3. SelectedValue —— 选项的值，为string，只读不写

4. SelectedItem.Text ——选项的文本内容，与 SelectedItem的值一样为 string，可读可写

5. SelectedItem.Value ——选项的值，与 SelectedValue的值一样为 string，可读可写

示例

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

<!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>
        <asp:DropDownList ID="DropDownList1" runat="server">
            <asp:ListItem Value="1">北京</asp:ListItem>
            <asp:ListItem Value="2">上海</asp:ListItem>
            <asp:ListItem Value="3">广州</asp:ListItem>
        </asp:DropDownList>
        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="check" /><br />
        <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
        <br />
        <asp:Label ID="Label2" runat="server" Text=""></asp:Label>
        <br />
        <asp:Label ID="Label3" runat="server" Text=""></asp:Label><br />
        <asp:Label ID="Label4" runat="server" Text=""></asp:Label>
        <br />
        <asp:Label ID="Label5" runat="server" Text=""></asp:Label>
    
    </div>
    </form>
</body>
</html>

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;

public partial class dropdown : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Label1.Text = "selectedIndex=" + DropDownList1.SelectedIndex;
        Label2.Text = "selectedItem=" + DropDownList1.SelectedItem;
        Label3.Text = "selectedValue=" + DropDownList1.SelectedValue;
        Label4.Text = "selectedItem.text=" + DropDownList1.SelectedItem.Text;
        Label5.Text = "selectedItem.value=" + DropDownList1.SelectedItem.Value;
    }
}