ListBox中怎么实现多选并显示数据

ListBox中怎么实现多选并显示数据，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。

<%@ Page Language="C#" AutoEventWireup="true" Debug="true"%>  
<%@import namespace="System.Data"%>  
<%@import namespace="System.Data.SqlClient"%>  
<FORM RUNAT=< SPAN>"server">  
"ckbEmployees" runat="server" RepeatLayout="table" RepeatDirection="vertical" RepeatColumns="3" CellPadding="9" CellSpacing="18" TextAlign="right" OnSelectedIndexChanged="subListChange" AutoPostBack="true" />  

 
"dgEmployee" runat="server" />  
<SCRIPT LANGUAGE=< SPAN>"c#" runat="server">  
private void Page_load(object sender,System.EventArgs e)  
{  
if(!IsPostBack)  
{  
   string strConnection ="server=.;uid=sa;pwd=sunix!;database=northwind";  
   string strSQLforCheckBoxes = "select LastName ,EmployeeID from employees order by lastname";  
   SqlConnection objConnection = new SqlConnection(strConnection);  
   SqlCommand objCommand = new SqlCommand(strSQLforCheckBoxes,objConnection);  
   objConnection.Open();  
   ckbEmployees.DataSource = objCommand.ExecuteReader();  
   ckbEmployees.DataTextField = "LastName";  
   ckbEmployees.DataValueField = "EmployeeID";  
   ckbEmployees.DataBind();  
   objConnection.Close();  
}  
}  
private void subListChange(object s,System.EventArgs e)  
{  
Response.Write("subListchange triggered
");  
string strWhereClause="";  
foreach (ListItem liThisOne in ckbEmployees.Items)  
{  
   if(liThisOne.Selected)  
   {  
    strWhereClause += "EmployeeID = " + liThisOne.Value + " OR ";  
   }  
}  
Response.Write("strWhereClause=
"+strWhereClause+"
");  
if(strWhereClause.Length>0)  
{  
   dgEmployee.Visible = true;  
   string str = strWhereClause.Substring(0,strWhereClause.Length - 3);  
   strWhereClause = " where " + str;  
   string strConnection = "server=.;uid=sa;pwd=sunix!;database=northwind";  
   string strSQLforGrid = "select TitleOfCourtesy,firstName,lastName,country,region,city,notes from employees " + strWhereClause;  
     //Response.Write(strSQLforGrid); sql语句之间的空格,否则出错  
   SqlConnection objConnection = new SqlConnection(strConnection);  
   SqlCommand objCommand = new SqlCommand(strSQLforGrid,objConnection);  
   Response.Write("strSQLforGrid=
"+strSQLforGrid+"
");  
   objConnection.Open();  
   dgEmployee.DataSource = objCommand.ExecuteReader();  
   dgEmployee.DataBind();  
   objConnection.Close();  
}  
else 
{  
   dgEmployee.Visible = false;  
}  
}  
   

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