02-26C#三级省市区ajax联动控件,利用UpdatePanel，以及页面取值

第一步：设置界面

 1 <%@ Control Language="C#" AutoEventWireup="true" CodeFile="PCAControl.ascx.cs" Inherits="PCAControl" %>
 2 <asp:ScriptManager ID="ScriptManager1" runat="server">
 3 </asp:ScriptManager>
 4 <asp:UpdatePanel ID="UpdatePanel1" runat="server">
 5     <ContentTemplate>
 6         <asp:DropDownList ID="ddlProvice" runat="server" AppendDataBoundItems="true" AutoPostBack="true"
 7             OnSelectedIndexChanged="ddlProvice_SelectedIndexChanged">
 8             <asp:ListItem Text="-请选择省份-" Value=""></asp:ListItem>
 9         </asp:DropDownList>
10         <asp:DropDownList ID="ddlCity" runat="server" AutoPostBack="true"
11             onselectedindexchanged="ddlCity_SelectedIndexChanged">
12             <asp:ListItem Text="-请选择城市-" Value=""></asp:ListItem>
13         </asp:DropDownList>
14         <asp:DropDownList ID="ddlArea" runat="server">
15             <asp:ListItem Text="-请选择县区-" Value=""></asp:ListItem>
16         </asp:DropDownList>
17     </ContentTemplate>
18 </asp:UpdatePanel> 

第二步：C#写方法函数

 1 using System.Collections.Generic;
 2 using System.Linq;
 3 using System.Web;
 4 using System.Data;
 5 using System.Web.UI;
 6 using System.Web.UI.WebControls;
 7
 8 public partial class PCAControl : System.Web.UI.UserControl
 9 {
10
11     protected void Page_Load(object sender, EventArgs e)
12     {
13         if (!IsPostBack)
14         {
15             BindProvince();
16         }
17     }
18
19     //加载省份
20     protected void BindProvince()
21     {
22         DataTable dt = Maticsoft.DBUtility.DbHelperOra.Query("SELECT DISTINCT PROVINCE FROM SY_CITYCODE  GROUP   BY PROVINCE").Tables[0];
23         ddlProvice.DataTextField = "PROVINCE";
24         ddlProvice.DataValueField = "PROVINCE";
25         ddlProvice.DataSource = dt;
26         ddlProvice.DataBind();
27     }
28
29     //加载城市
30     protected void ddlProvice_SelectedIndexChanged(object sender, EventArgs e)
31     {
32         string SelectPro = ddlProvice.SelectedValue;
33         if (!string.IsNullOrEmpty(SelectPro))
34         {
35             ddlCity.Items.Clear();
36             ddlCity.AppendDataBoundItems = true;
37             ddlCity.Items.Insert(0, new ListItem("-请选择城市-", ""));
38             DataTable dt1 = Maticsoft.DBUtility.DbHelperOra.Query("SELECT CITY FROM SY_CITYCODE Where PROVINCE=‘" + SelectPro + "‘  Group By City").Tables[0];
39             ddlCity.DataTextField = "CITY";
40             ddlCity.DataValueField = "CITY";
41             ddlCity.DataSource = dt1;
42             ddlCity.DataBind();
43         }
44     }
45
46     //加载县区
47     protected void ddlCity_SelectedIndexChanged(object sender, EventArgs e)
48     {
49         string SelectCity = ddlCity.SelectedValue;
50         if (!string.IsNullOrEmpty(SelectCity))
51         {
52             ddlArea.Items.Clear();
53             ddlArea.AppendDataBoundItems = true;
54             ddlArea.Items.Insert(0, new ListItem("-请选择县区-", ""));
55             DataTable dt2 = Maticsoft.DBUtility.DbHelperOra.Query("SELECT AREA FROM SY_CITYCODE Where CITY=‘" + SelectCity + "‘").Tables[0];
56             ddlArea.DataTextField = "AREA";
57             ddlArea.DataValueField = "AREA";
58             ddlArea.DataSource = dt2;
59             ddlArea.DataBind();
60         }
61     }
62 } 

第三步：在页面中调用函数

1 protected void Button1_Click(object sender, EventArgs e)
2 {
3     string SelectedProv = ((DropDownList)PCAControl1.FindControl("ddlProvice")).SelectedValue;
4     string SelectedCity = ((DropDownList)PCAControl1.FindControl("ddlCity")).SelectedValue;
5     string SelectedArea = ((DropDownList)PCAControl1.FindControl("ddlArea")).SelectedValue;
6     MSCL.JsHelper.Alert(SelectedProv + "-" + SelectedCity + "-" + SelectedArea, Page);
7 }