两个ListBox的互动方法

来源：http://cfeng518.blog.163.com/blog/static/174677322007112011553642/

效果:

ASPX页面: 

 <table>
   <tbody>
      <tr>
         <td>
            <asp:ListBox ID="lbLeft" runat="server" SelectionMode="Multiple">
               <asp:ListItem>添加名字</asp:ListItem>
               <asp:ListItem>出生年月</asp:ListItem>
            </asp:ListBox>
         </td>
         <td style="width: 27px">
            <asp:Button ID="btnToRight" runat="server" Text=">>" 
                    OnClick="btnToRight_Click" />
            <br />
            <asp:Button ID="btnToLeft" runat="server" Text="<<" 
                        OnClick="btnToLeft_Click" />
            </td>
         <td style="width: 3px">
            <asp:ListBox ID="lbRight" runat="server" 
                    SelectionMode="Multiple"></asp:ListBox></td>
      </tr>
   </tbody>
</table>
<asp:Label ID="lblMsg" runat="server"></asp:Label>

CS Code ：

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 Test1 : System.Web.UI.Page
   {
      protected void Page_Load ( object sender , EventArgs e )
      {

      }
      protected void btnToRight_Click(object sender, EventArgs e)
      {
         if(lbLeft.SelectedItem != null)
         {
            AddItemFromSourceListBox(lbLeft, lbRight);

            RemoveSelectedItem(lbLeft);

            lblMsg.Text=""; //注意:为什么要这一行?
            
            foreach(ListItem item in lbRight.Items)
            {
               if(item.Selected)
                  lblMsg.Text +=item.Text;
            }
         }
      }

      protected void btnToLeft_Click(object sender, EventArgs e)
      {
         if(lbRight.SelectedItem != null)
         {            
            AddItemFromSourceListBox(lbRight, lbLeft);
            RemoveSelectedItem(lbRight);
         }
      }

      private void RemoveSelectedItem(ListBox listControl)
      {         
         while(listControl.SelectedIndex != -1)
         {
            listControl.Items.RemoveAt(listControl.SelectedIndex);
         }         
      }

      private void AddItemFromSourceListBox(ListBox sourceBox,ListBox targetBox)
      {
         foreach(ListItem item in sourceBox.Items)
         {
            if(item.Selected == true && !targetBox.Items.Contains(item))
            {
               targetBox.Items.Add(item);
            }
         }
      }

}