前台代码：
1 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="iframe_dropdown.aspx.cs" Inherits="Admin_iframe_dropdown" %> 2 3 4 <!DOCTYPE html> 5 6 <html xmlns="http://www.w3.org/1999/xhtml"> 7 <head runat="server"> 8 <title></title> 9 </head> 10 <body> 11 <form id="form1" runat="server"> 12 <asp:ScriptManager ID="ScriptManager1" runat="server" /> 13 <div style="float: left" > 14 <asp:UpdatePanel ID="UpdatePanel1" runat="server"> 15 <ContentTemplate> 16 <asp:DropDownList ID="DropDownList1" runat="server" Width="105px" AutoPostBack="true" 17 OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" > 18 </asp:DropDownList> 19 <asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="true" Width="105px" 20 OnSelectedIndexChanged="DropDownList2_SelectedIndexChanged"> 21 </asp:DropDownList> 22 <asp:DropDownList ID="DropDownList3" runat="server" AutoPostBack="true" Width="105px" 23 OnSelectedIndexChanged="DropDownList3_SelectedIndexChanged"> 24 </asp:DropDownList> 25 <asp:DropDownList ID="DropDownList4" runat="server" AutoPostBack="true" Width="105px" 26 OnSelectedIndexChanged="DropDownList4_SelectedIndexChanged"> 27 </asp:DropDownList> 28 </ContentTemplate> 29 </asp:UpdatePanel> 30 </div> 31 <div style="float: left" > 32 </div> 33 34 </form> 35 </body> 36 </html>
后台代码：
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Web; 5 using System.Web.UI; 6 using System.Web.UI.WebControls; 7 using System.Data; 8 using System.Data.SqlClient; 9 using System.Collections; 10 using System.Text; 11 12 13 public partial class Admin_iframe_dropdown : System.Web.UI.Page 14 { 15 protected void Page_Load(object sender, EventArgs e) 16 { 17 18 if (!IsPostBack) 19 { 20 Db1DataBind(); 21 Db2DataBind(); 22 Db3DataBind(); 23 Db4DataBind(); 24 } 25 } 26 27 protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) 28 { 29 Db2DataBind(); 30 Db3DataBind(); 31 Db4DataBind(); 32 } 33 protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e) 34 { 35 Db3DataBind(); 36 Db4DataBind(); 37 } 38 protected void DropDownList3_SelectedIndexChanged(object sender, EventArgs e) 39 { 40 Db4DataBind(); 41 } 42 protected void DropDownList4_SelectedIndexChanged(object sender, EventArgs e) 43 { 44 45 } 46 47 public void Db1DataBind() 48 { 49 string sqlStr = "select ModID,ModName,ParentID from Modules where ParentID=0000"; 50 FillDropList(sqlStr, DropDownList1); 51 52 } 53 public void Db2DataBind() 54 { 55 int PreID = Convert.ToInt32(DropDownList1.SelectedValue); 56 string sqlStr1 = "Select ModID,ModName,ParentID from Modules where ParentID='" + PreID.ToString() + "'"; 57 FillDropList(sqlStr1, DropDownList2); 58 } 59 public void Db3DataBind() 60 { 61 int PreID = Convert.ToInt32(DropDownList2.SelectedValue); 62 string sqlStr2 = "Select ModID,ModName,ParentID from Modules where ParentID='" + PreID.ToString() + "'"; 63 FillDropList(sqlStr2, DropDownList3); 64 } 65 public void Db4DataBind() 66 { 67 string PreID = Convert.ToString(DropDownList3.SelectedValue); 68 string sqlStr3 = "Select ModID,ModName,ParentID from Modules where ParentID='" + PreID.ToString() + "'"; 69 FillDropList(sqlStr3, DropDownList4); 70 } 71 public void FillDropList(string SQLString, DropDownList drp) 72 { 73 SqlConnection connection = new SqlConnection("database=ZJExpress;server=(local);uid=sa;pwd=hellocheng"); 74 SqlCommand cmd = new SqlCommand(SQLString, connection); 75 SqlDataAdapter sda = new SqlDataAdapter(cmd); 76 DataSet ds = new DataSet(); 77 sda.Fill(ds, "DropList"); 78 drp.DataSource = ds.Tables["DropList"].DefaultView; 79 drp.DataTextField = ds.Tables["DropList"].Columns[1].ColumnName; 80 drp.DataValueField = ds.Tables["DropList"].Columns[0].ColumnName; 81 drp.DataBind(); 82 } 83 }
参考链接http://blog.csdn.net/wxd_860825/article/details/4563368