Hi, I hope some one can help with this. I have a basic webform with 2
DropDownLists and a single DataGrid. What I am trying to do is populate the
first DDList from a dataset on Form_Load. I then want to use this 1st DDList
to populate the 2nd DDList via the SelectedIndexCh ange Event.
So far so good. all works up to this point.
The next thing I'm trying to do is to use the 2nd DDList value in a queery
to populate the Datagrid also via the SelectedIndexCh ange Event. This is
where I run into the problem: When the 2nd DDList does it's postback it
seems to loose it's Values and the SelectedIndexCh anged Event won't fire.
If I pre-populate the 2nd DDList manually from IDE before runtime, then the
problem disappears.
any Ideas anyone?
Thanks
WebForm1.aspx :
***********
<%@ Page Language="vb" AutoEventWireup ="false" Codebehind="Web Form1.aspx.vb"
Inherits="shop. WebForm1"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<title>WebForm1 </title>
<meta content="Micros oft Visual Studio .NET 7.1" name="GENERATOR ">
<meta content="Visual Basic .NET 7.1" name="CODE_LANG UAGE">
<meta content="JavaSc ript" name="vs_defaul tClientScript">
<meta content="http://schemas.microso ft.com/intellisense/ie5"
name="vs_target Schema">
</HEAD>
<body MS_POSITIONING= "GridLayout ">
<form id="Form1" method="post" runat="server">
<asp:DropDownLi st id="DDL_Top_Cat egory" style="Z-INDEX: 101;
LEFT: 24px; POSITION: absolute; TOP: 8px"
runat="server" AutoPostBack="T rue"
Width="112px"></asp:DropDownLis t>
<asp:DataGrid id="DG_Selectio ns" style="Z-INDEX: 103; LEFT:
16px; POSITION: absolute; TOP: 64px"
runat="server"> </asp:DataGrid>
<asp:DropDownLi st id="DDL_Sub_Cat egory" style="Z-INDEX: 102;
LEFT: 24px; POSITION: absolute; TOP: 32px"
runat="server" Width="112px"
AutoPostBack="T rue"></asp:DropDownLis t></form>
</body>
</HTML>
WebForm1.aspx.v b :
**************
Imports System.Data.Sql Client
Public Class WebForm1
Inherits System.Web.UI.P age
Public DS_Selections As New DataSet
#Region " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnos tics.DebuggerSt epThrough()> Private Sub
InitializeCompo nent()
End Sub
Protected WithEvents DDL_Top_Categor y As
System.Web.UI.W ebControls.Drop DownList
Protected WithEvents DDL_Sub_Categor y As
System.Web.UI.W ebControls.Drop DownList
Protected WithEvents DG_Selections As System.Web.UI.W ebControls.Data Grid
'NOTE: The following placeholder declaration is required by the Web Form
Designer.
'Do not delete or move it.
Private designerPlaceho lderDeclaration As System.Object
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeCompo nent()
End Sub
#End Region
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Load
If Not Page.IsPostBack = True Then
'Populate DDL_Top_Categor y
Dim ds1 As New DataSet
Dim sConn As SqlConnection = New SqlConnection(" Data
Source=*****;In itial Catalog=*****;U ser Id=*****;Passwo rd=*****")
Dim sq1 As SqlDataAdapter = New SqlDataAdapter( "SELECT * FROM
Product_Top_Cat egory", sConn)
sq1.Fill(ds1)
DDL_Top_Categor y.DataSource = ds1.Tables(0)
DDL_Top_Categor y.DataTextField =
ds1.Tables(0).C olumns(1).Colum nName.ToString
DDL_Top_Categor y.DataValueFiel d =
ds1.Tables(0).C olumns(2).Colum nName.ToString
DDL_Top_Categor y.DataBind()
End If
End Sub
Private Sub DDL_Top_Categor y_SelectedIndex Changed(ByVal sender As
Object, ByVal e As System.EventArg s) Handles
DDL_Top_Categor y.SelectedIndex Changed
'Fill DDL_Sub_Categor y depending on DDL_Top_Categor y Selection
DDL_Sub_Categor y.Items.Clear()
Dim ds1 As New DataSet
Dim sConn As SqlConnection = New SqlConnection(" Data
Source=*****;In itial Catalog=*****;U ser Id=*****;Passwo rd=*****")
Dim sq1 As SqlDataAdapter = New SqlDataAdapter( "SELECT * FROM
Product_Sub_Cat egory WHERE Category_Level= '" & DDL_Top_Categor y.SelectedValue
& "'", sConn)
sq1.Fill(ds1)
DDL_Sub_Categor y.DataSource = ds1.Tables(0)
DDL_Sub_Categor y.DataTextField =
ds1.Tables(0).C olumns(1).Colum nName.ToString
DDL_Sub_Categor y.DataValueFiel d =
ds1.Tables(0).C olumns(2).Colum nName.ToString
DDL_Sub_Categor y.DataBind()
End Sub
Private Sub DDL_Sub_Categor y_SelectedIndex Changed(ByVal sender As
Object, ByVal e As System.EventArg s) Handles
DDL_Sub_Categor y.SelectedIndex Changed
'Fill DG_Selections depending on DDL_Sub_Categor y Selection
Dim sConn As SqlConnection = New SqlConnection(" Data
Source=*****;In itial Catalog=*****;U ser Id=*****;Passwo rd=*****")
Dim sq1 As SqlDataAdapter = New SqlDataAdapter( "SELECT * FROM
Products WHERE Product_ID='" & DDL_Sub_Categor y.SelectedValue & "' AND
Product_In_Use= 1", sConn)
sq1.Fill(DS_Sel ections)
DG_Selections.D ataSource = DS_Selections
DG_Selections.D ataBind()
End Sub
End Class
--
Before you judge a man, walk a mile in his shoes. Then who cares! You are a
mile away and you have his shoes.
