302班

public void dplistBind()
  {   
   this.DropDownList1.DataTextField="";
   SqlConnection con=DB.createCon();
   con.Open();
   string strName="select * from tch_gaikuang where zaijian=0";
   SqlCommand cmd=new SqlCommand(strName,con);
   SqlDataReader sdr=cmd.ExecuteReader();
   this.DropDownList1.DataSource=sdr;
   this.DropDownList1.DataTextField="name";
   this.DropDownList1.DataValueField="name";
   this.DropDownList1.DataBind();
   sdr.Close(); 
  
  }

以ASP.NET為例實現省市區的三級聯動 
 public void getDdlInfo(DropDownList province,DropDownList city,DropDownList town,Page myPage)
{ //初始化省 string sql="select 序號,省名 from 省表";   
     SqlCommand comm=new SqlCommand(sql,conn);
 province.Items.Clear();
province.Items.Add(new ListItem("-=請選擇=-","0"));
conn.Open();
SqlDataReader dr=comm.ExecuteReader();
while(dr.Read())
{
 province.Items.Add(new ListItem(dr[1].ToString(),dr[0].ToString()));
}
dr.Close();
//初始化市 city.Items.Add(new ListItem("-=請選擇=-","0"));
//初始化區 to

含類的下拉框

public void Goverment_dplistBind()
  {    
   string strconn = System.Configuration.ConfigurationSettings.AppSettings["SqlConnectionString"];//從Web.config中讀取
   SqlConnection con =new SqlConnection(strconn);
   con.Open();
   string strSql="select * from links where link_Class='政府部門'";
   SqlCommand cmd=new SqlCommand(strSql,con);
   SqlDataReader sdr=cmd.ExecuteReader();
   this.ddl_Goverment.DataSource=sdr;
   this.ddl_Goverment.DataTextField="link_Name";
   this.ddl_Goverment.DataValueField="link_Name";
   this.ddl_Goverment.DataBind();
//下列做的初始化工作，如果不這樣就會使得數據庫中的一項被初始化操作覆蓋掉，兩種方法
   this.ddl_Goverment.Items.Insert(0,"政府部門");
   //this.ddl_Goverment.Items.Add(new ListItem("政府部門",""));
   //this.ddl_Goverment.SelectedIndex=this.ddl_Goverment.Items.IndexOf(this.ddl_Goverment.Items.FindByText("政府部門"));
   sdr.Close();