你好:)这道题不建议用TableAdapter做,你删除先前全部的东西,拖拽两个下拉框到页面上——假设你的数据表有两个——省(ID,name)市区(ID,NAME,FID)——FID就是“省”的外键。 直接编码如下:1)双击aspx页面,然后在Page_Load中先加载省的所有列表:if(!IsPostBack){using (SqlDataAdapter adapter = new SqlDataAdapter("select * from 省",new SqlConnection(数据库连接字符串)){ DataTable dt = new DataTable(); adapter.Fill(dt); Dropdownlist1.DataSource = dt; Dropdownlist1.DataTextField="name"; Dropdownlist1.DataValueField="ID"; Dropdownlist1.DataBind();}} 然后把“省”的AutoPostBack设置成True 2)双击“省”的下拉框,在SelectIndexChanged事件中:using (SqlDataAdapter adapter = new SqlDataAdapter("select * from 市区 where fid="+Dropdownlist1.SelectedValue.ToString(),new SqlConnection(数据库连接字符串)){DataTable dt = new DataTable();adapter.Fill(dt);Dropdownlist2.DataSource = null;Dropdownlist2.DataSource = dt;Dropdownlist2.DataTextField="name";Dropdownlist2.DataValueField="ID";Dropdownlist2.DataBind();}