个人学习代码保存:例7.ListBox小代码

前台代码：Default.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">

</head>

<body>

<div>

<asp:ListBox ID="ListBox1" runat="server" SelectionMode="Multiple"></asp:ListBox> 

<asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text=">" />

<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text=">>" />

<asp:ListBox ID="ListBox2" runat="server" SelectionMode="Multiple"></asp:ListBox></div>

</form>

</body>

</html>

后台代码：

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.Data.SqlClient;

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

{

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

this.ListBindData();

}

public void ListBindData()

{

string connstr=ConfigurationManager.AppSettings["ConnectionString"].ToString();

SqlConnection con = new SqlConnection(connstr);

if (con.State.Equals(ConnectionState.Closed))

{

con.Open();

}

SqlCommand cmd = new SqlCommand("select * from guestbook",con);

SqlDataReader sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

//这是第一种方法了

//while (sdr.Read())

//{

// ListBox1.Items.Add(new ListItem(sdr["title"].ToString(),sdr["id"].ToString()));

//}

ListBox1.DataSource = sdr;

ListBox1.DataTextField = "title";

ListBox1.DataValueField = "id";

ListBox1.DataBind();

}

protected void Button1_Click(object sender, EventArgs e)

{

foreach (ListItem item in ListBox1.Items)

{

ListBox2.Items.Add(item);

}

ListBox1.Items.Clear();

}

protected void Button2_Click(object sender, EventArgs e)

{

ListBox2.Items.Add(ListBox1.SelectedItem);

ListBox1.SelectedIndex = -1;

ListBox2.SelectedIndex = -1;

}