两个ListBox的互动

适合:
.Net 2.0
VS2005
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);
            }
         }
      }

}