实现无刷新闪烁二级联动下拉菜单

-- 父表
create   table  tb_parent(
-- 主键
ids  int   constraint  pk_tb_parent_ids  primary   key ,
parentName  nvarchar ( 1000 )
)
go

insert   into  tb_parent
     select   1 , ' aaa '
     union   all
     select   2 , ' bbb '
     union   all
     select   3 , ' ccc '
go

-- 子表
create   table  tb_child(
parentId  int   ,
childId  int  ,
childName  nvarchar  ( 1000 ),
-- parentId外键
constraint  fk_tb_child_tb_parent_parentId 
     FOREIGN   KEY  (parentId)     
         REFERENCES  tb_parent(ids)
)
go


insert   into  tb_child
     select   1 , 101 , ' a_1 '
     union   all
     select   1 , 102 , ' a_2 '
go
insert   into  tb_child
     select   2 , 201 , ' b_1 '
     union   all
     select   2 , 202 , ' b_2 '
go
insert   into  tb_child
     select   3 , 301 , ' c_1 '
     union   all
     select   3 , 302 , ' c_2 '
     union   all
     select   3 , 303 , ' c_3 '
go

-- 得到父表数据
create   proc  proc_GetparentData
as
SELECT   [ ids ] ,  [ parentName ]  
     FROM   [ tb_parent ]
go


-- 得到子表数据
create   proc  proc_GetchildData
as
SELECT   [ parentId ] ,  [ childId ] ,  [ childName ]  
     FROM   [ tb_child ]
go

-- 由父id得到子表数据
create   proc  proc_GetchildDataBYparentId
@parentId   int
as
SELECT   [ parentId ] ,  [ childId ] ,  [ childName ]  
     FROM   [ tb_child ]
     where  parentId = @parentId
go

 1   <% @ Page language = " c# "  Codebehind = " WebForm5.aspx.cs "  AutoEventWireup = " false "  Inherits = " webtest.WebForm5 "   %>
 2   <! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"  >
 3   < HTML >
 4        < HEAD >
 5            < title > WebForm5 </ title >
 6            < meta  content ="Microsoft Visual Studio .NET 7.1"  name ="GENERATOR" >
 7            < meta  content ="C#"  name ="CODE_LANGUAGE" >
 8            < meta  content ="JavaScript"  name ="vs_defaultClientScript" >
 9            < meta  content ="http://schemas.microsoft.com/intellisense/ie5"  name ="vs_targetSchema" >
10        </ HEAD >
11        < body  MS_POSITIONING ="GridLayout" >
12            < form  id ="Form1"  method ="post"  runat ="server" >
13               父: < asp:dropdownlist  id ="DropDownList_parent"  runat ="server"  onChange ="changevalue(document.Form1.DropDownList_parent.options[document.Form1.DropDownList_parent.selectedIndex].value)"
14                   Width ="272px" ></ asp:dropdownlist >
15                < br >
16               子: < asp:dropdownlist  id ="DropDownList_child"  runat ="server"  Width ="272px" ></ asp:dropdownlist >
17                < br >
18                < asp:label  id ="msgLabel"  runat ="server"  Width ="416px" ></ asp:label >
19                < br >
20                < asp:Button  id ="Buttonok"  runat ="server"  Text ="click" ></ asp:Button ></ form >
21        </ body >
22   </ HTML >

  1 using  System;
  2 using  System.Collections;
  3 using  System.ComponentModel;
  4 using  System.Data;
  5 using  System.Data.SqlClient;
  6 using  System.Drawing;
  7 using  System.Web;
  8 using  System.Web.SessionState;
  9 using  System.Web.UI;
 10 using  System.Web.UI.WebControls;
 11 using  System.Web.UI.HtmlControls;
 12 using  System.Text;
 13
 14 using  Microsoft.ApplicationBlocks.Data;
 15
 16 namespace  webtest
 17 {
 18      public   class  WebForm5 : System.Web.UI.Page
 19      {
 20          protected  System.Web.UI.WebControls.DropDownList DropDownList_parent;
 21          protected  System.Web.UI.WebControls.DropDownList DropDownList_child;
 22         
 23          protected  System.Web.UI.WebControls.Label msgLabel;
 24          protected  System.Web.UI.WebControls.Button Buttonok;
 25
 26          readonly   string  conString = " uid=sa;pwd=123;database=TestDataBase " ;
 27     
 28          private   void  Page_Load( object  sender, System.EventArgs e)
 29          {    
 30                 regJS();
 31                 Bind();
 32         }
 33
 34          private   void  regJS()
 35          {
 36             SqlDataReader rs = this .GetchildData();
 37             StringBuilder sb = new  StringBuilder( 1000 );
 38
 39             sb.Append( " <Script Language=JavaScript> " );
 40             sb.Append(Environment.NewLine);
 41             
 42             sb.Append( " arr=new Array(); " );
 43             sb.Append(Environment.NewLine);
 44             
 45              int  i = 0 ;
 46              while (rs.Read())
 47              {
 48                 sb.AppendFormat( " arr[{0}]=new Array('{1}','{2}','{3}') " ,i,rs[ " parentId " ],rs[ " childId " ],rs[ " childName " ]);
 49                 sb.Append(Environment.NewLine);
 50                 i = i + 1 ;
 51             }
 52             
 53              if  (  ! rs.IsClosed )
 54              {
 55                 rs.Close();
 56             }
 57
 58             sb.Append(Environment.NewLine);
 59             sb.AppendFormat( " var counts={0} " ,i);
 60             sb.Append(Environment.NewLine);
 61             sb.Append( " function changevalue(parentId) " );
 62             sb.Append(Environment.NewLine);
 63             sb.Append( " { " );
 64             sb.Append(Environment.NewLine);
 65             sb.Append( " document.Form1.DropDownList_child.length = 0; " );
 66             sb.Append(Environment.NewLine);
 67             sb.Append( " var i; " );
 68             sb.Append(Environment.NewLine);
 69             sb.Append( " for(i=0; i<counts; i++) " );
 70             sb.Append(Environment.NewLine);
 71             sb.Append( " { " );
 72             sb.Append(Environment.NewLine);
 73             sb.Append( " if(arr[i][0]==parentId) " );
 74             sb.Append(Environment.NewLine);
 75             sb.Append( " { " );
 76             sb.Append(Environment.NewLine);
 77             sb.Append( " document.Form1.DropDownList_child.options[document.Form1.DropDownList_child.length]=new Option(arr[i][2],arr[i][1]); " );
 78             sb.Append(Environment.NewLine);
 79             sb.Append( " } " );
 80             sb.Append(Environment.NewLine);
 81             sb.Append( " } " );
 82             sb.Append(Environment.NewLine);
 83             sb.Append( " } " );
 84             sb.Append(Environment.NewLine);
 85             sb.Append( " </script> " );            
 86                         
 87              if (  ! Page.IsClientScriptBlockRegistered( " jsScript " ))            
 88              {
 89                  this .RegisterClientScriptBlock( " jsScript " ,sb.ToString());
 90             }
 91         }
 92
 93          void  Bind()
 94          {
 95              // 获得父表
 96              this .DropDownList_parent.DataSource = SqlHelper.ExecuteReader(conString,CommandType.StoredProcedure, " proc_GetparentData " );
 97              this .DropDownList_parent.DataTextField = " parentName " ;
 98              this .DropDownList_parent.DataValueField = " ids " ;
 99              this .DropDownList_parent.DataBind();
100
101              // 根据父表id得子表
102              this .DropDownList_child.DataSource = GetchildData(Convert.ToInt32( this .DropDownList_parent.SelectedValue));
103              this .DropDownList_child.DataTextField = " childName " ;
104