asp.net 实现省市级联-----<简单方法1>

准备工作：数据库自带

1.前台代码部分:

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<asp:ScriptManager ID="ScriptManager1" runat="server">

      </asp:ScriptManager>

      <asp:UpdatePanel ID="UpdatePanel1" runat="server">

      <ContentTemplate>

        <asp:DropDownList ID="DropDownList1" runat="server"

          onselectedindexchanged="DropDownList1_SelectedIndexChanged"

          ontextchanged="DropDownList1_TextChanged" AutoPostBack=true>

      </asp:DropDownList>

      <br />

      <asp:DropDownList ID="ddl_city" runat="server"

          onselectedindexchanged="ddl_city_SelectedIndexChanged">

      </asp:DropDownList>

    </ContentTemplate>

      </asp:UpdatePanel>

2.后台代码部分:

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protected void Page_Load(object sender, EventArgs e)

   {

       if (!IsPostBack)

       {

           string sqlstr = "select * from promary";

           DataTable dt = sqlhelper.ExcuteDataTable(sqlstr);

           //1.显示什么数据

           DropDownList1.DataTextField = "proName";

           DropDownList1.DataValueField = "proId";

           DropDownList1.DataSource = dt;

           DropDownList1.DataBind();

       }

       

        

   }

  

   protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)

   {

       string proId = DropDownList1.SelectedValue.ToString();

       string sqlstr = string.Format("select * from city where proID={0}", proId);

       DataTable dt = sqlhelper.ExcuteDataTable(sqlstr);

       ddl_city.DataTextField = "cityName";

       ddl_city.DataValueField = "cityId";

       ddl_city.DataSource = dt;

       ddl_city.DataBind();

   }