webform 联动查询代码

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Drawing;





public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!IsPostBack)//获取一个值,该值指示页面是第一次呈现还是为了相应回发而加载

        {

            Dropdownlist();

        }

    }





    //第一种显示方法

    public void Dropdownlist()

    {

        List<ChinaStates> list = new ChinaBF().SelectByParent("0001");

        foreach (ChinaStates data in list)

        {

            ListItem it = new ListItem(data.AreaName,data.AreaCode);

            DropDownList1.Items.Add(it);

        }  

    }

//第二种显示方法

    public void BindDropdownlist()

    {

        List<ChinaStates> list = new ChinaBF().SelectByParent("0001");

        DropDownList1.DataSource = list;

        DropDownList1.DataTextField = "AreaName";

        DropDownList1.DataValueField = "AreaCode";

        DropDownList1.DataBind();

    }



    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)

    {

        //Label1.Text = DropDownList1.SelectedItem.Text;

        string a = DropDownList1.SelectedItem.Value;

        List<ChinaStates> list = new ChinaBF().SelectByParent(a);

        DropDownList2.DataSource = list;

        DropDownList2.DataTextField = "AreaName";

        DropDownList2.DataValueField = "AreaCode";

        DropDownList2.DataBind();



        string b = DropDownList2.SelectedItem.Value;

        List<ChinaStates> list1 = new ChinaBF().SelectByParent(b);

        DropDownList3.DataSource = list1;

        DropDownList3.DataTextField = "AreaName";

        DropDownList3.DataValueField = "AreaCode";

        DropDownList3.DataBind();

    }





    protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)

    {

         string b = DropDownList2.SelectedItem.Value;

        List<ChinaStates> list1 = new ChinaBF().SelectByParent(b);

        DropDownList3.DataSource = list1;

        DropDownList3.DataTextField = "AreaName";

        DropDownList3.DataValueField = "AreaCode";

        DropDownList3.DataBind();

    }

    //当点击注册的时候,判断验证码格式输入是否正确



    protected void Button1_Click(object sender, EventArgs e)

    {

        if (TextBox1.Text.ToUpper().Trim() == Session["ValidateCode"].ToString().ToUpper().Trim())

        {

            Response.Write("<script>alert('登陆成功')</script>");

          

        }

        else

        {

            Response.Write("<script>alert('验证码格式不正确')</script>");

        }

    }

}

方法里的代码

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;



/// <summary>

/// ChinaBF 的摘要说明

/// </summary>

public class ChinaBF

{



    private DataClassesDataContext _Context;

    public ChinaBF()

    {

        //

        // TODO: 在此处添加构造函数逻辑

        //



   _Context=new DataClassesDataContext ();

        

    }



    public List<ChinaStates> Select()

    {

        return _Context.ChinaStates.ToList();

    }



    public List<ChinaStates> SelectByParent(string id)

    {

        return _Context.ChinaStates.Where(p=>p.ParentAreaCode==id) .ToList();

    }

}


Html里的源代码

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



<!DOCTYPE html>



<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>

    <title></title>

</head>

<body>

    <form id="form1" runat="server">

    <div>

    

    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

        <br />

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

        </asp:ScriptManager>

        <br />

        <asp:UpdatePanel ID="UpdatePanel1" runat="server" ChildrenAsTriggers="False" UpdateMode="Conditional">

            <ContentTemplate>

                &nbsp;&nbsp; 家庭住址:省份: 

                <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">

                </asp:DropDownList>

                &nbsp;市:<asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList2_SelectedIndexChanged">

                </asp:DropDownList>

                &nbsp; 区<asp:DropDownList ID="DropDownList3" runat="server">

                </asp:DropDownList>

<br />

            </ContentTemplate>

        </asp:UpdatePanel>

        <br />

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

        <br />

        <br />

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 请输入验证码:<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

&nbsp;&nbsp;&nbsp; 验证码:<asp:Image ID="CreateImage" runat="server" />

        <br />

        <br />

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="注册" />



       

      

    

    </div>

    </form>

</body>

</html>

 

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