省市之二 ------------------后台实现DropDownList联动

在网上看了很多,自己为了锻炼一下自己写了一个小的省市的二级联动。运行是可以的,请高手们多指教。

前台页面:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="DropDownhoutai.aspx.cs" Inherits="DropDownhoutai" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>DropdownList联动</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        省份:<asp:DropDownList ID="ddlProvince" runat="server" OnSelectedIndexChanged="ddlProvince_SelectedIndexChanged" AutoPostBack ="true" ></asp:DropDownList>
        市:<asp:DropDownList ID="ddlCity" runat="server"></asp:DropDownList>   
    </div>
    </form>
</body>
</html>

 

后台页面:

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public partial class DropDownhoutai : System.Web.UI.Page
{
    static string connString = "server=localhost;database=NationalAll;uid=sa;pwd=123456;";
    SqlConnection con = new SqlConnection(connString);
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            SqlDataAdapter sda = new SqlDataAdapter("select * from Province", con);
            DataSet dt = new DataSet();
            sda.Fill(dt);
            ddlProvince.DataSource = dt.Tables[0].DefaultView;
            ddlProvince.DataTextField = "ProName";
            ddlProvince.DataValueField = "ProId";
            ddlProvince.DataBind();
            ddlProvince.Items.Insert(0, new ListItem("--请选择--", "0"));
            ddlCity.Items.Insert(0, new ListItem("--请选择--", "0"));
        }
    }
    protected void ddlProvince_SelectedIndexChanged(object sender, EventArgs e)
    {
        BindCity(int.Parse(this.ddlProvince.SelectedItem.Value));
    }

    protected void BindCity(int ProID)
    {
        SqlCommand command = new SqlCommand("select * from City where ProID=@ProID",con);
        command.Parameters.Add(new SqlParameter("@ProID", ProID));
        DataSet ds = new DataSet();
        SqlDataAdapter da = new SqlDataAdapter(command);
        da.Fill(ds);
        ddlCity.DataSource = ds.Tables[0].DefaultView;
        ddlCity.DataTextField = "CityName";
        ddlCity.DataValueField = "CityID";
        ddlCity.DataBind();
    }
}

如果大家有更好的可以回帖,希望大家多给点意见。谢谢!!!!

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