getting event to fire from DropDownList user control

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getting event to fire from DropDownList user control

Last post 06-29-2007 9:26 AM by GrandVizier. 6 replies.

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getting event to fire from DropDownList user control

06-28-2007, 9:47 PM

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GrandVizier
Joined on 06-11-2007, 1:19 PM
Posts 62

Hej

I'm trying to set up a dropdownlist as a user control and everything has been going ok until trying to get the SelectedIndexChanged event to fire - in fact its not even the event that I need to get working but rather having access to the SelectedItem.Value - I've been working with ASP.Net for a while now but I'm new to user controls (really looking forward to using their potential) - I've followed several tutorials and forum posts but I just can't figure out what I'm missing - I've supplied the majority of the code I'm using

'USER CONTROL
Protected WithEvents ddl As System.Web.UI.WebControls.DropDownList
Private SelValue As Integer

    Public Event ListChanged(ByVal sender As Object, ByVal e As ListArgs)

    Protected Sub ddl_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddl.SelectedIndexChanged
        Dim la As New ListArgs
        la.itemValue = ddl.SelectedItem.Value
        SelValue = ddl.SelectedItem.Value
        RaiseEvent ListChanged(sender, la)
    End Sub

    Public Class ListArgs
        Inherits EventArgs
        Public itemValue As Integer
    End Class

   Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        If Not IsPostBack Then
            'Data binding code is here
        End If
    End Sub

    'as you can see I tried different techniques with this property
    Public Property SelectedItemValue() As Integer
        Get
            Return SelValue
        End Get
        Set(ByVal Value As Integer)
            SelValue = Me.ddl.SelectedValue
        End Set
    End Property


<asp:dropdownlist id="ddl" runat="server" AutoPostBack="True"></asp:dropdownlist>

'Web Form
'These are the methods that I expected to be working but ucDropDownList1_ListChanged never seems to be called
    Private Sub Button1_ServerClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.ServerClick
        Response.Redirect("newPage.aspx?ID=" & ucDropDownList1.SelValue)
    End Sub

    Private Sub ucDropDownList1_ListChanged(ByVal sender As System.Object, ByVal e As LaResBeer.ucDropDownList.ListArgs) Handles ucDropDownList1.ListChanged
        Label1.Text = e.itemValue.ToString
        ucDropDownList1.SelValue = e.itemValue
    End Sub

<%@ Page Language="vb" AutoEventWireup="false"%>
<%@ Register TagPrefix="uc1" TagName="ucDropDownList" src="ucDropDownList.ascx" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
.....
<uc1:ucDropDownList id="UcDropDownList1" runat="server"></uc1:ucDropDownList>

hopefully somebody can see what I'm doing wrong and help me fix this - thanks

Filed under: DropDownList, User Controls, event

Re: getting event to fire from DropDownList user control

06-28-2007, 10:35 PM

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zaladane
Joined on 06-19-2007, 6:44 AM
California
Posts 178

Oups!

Still in search of the far side.
--------------------------------
A code snippet may help you, but a reference to the doc will teach you something for later...Don't just try to solve somebody's problem with a snippet, teach him how to solve it.

Re: getting event to fire from DropDownList user control

06-28-2007, 10:38 PM

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mbanavige
Joined on 11-06-2003, 1:29 PM
New England, USA
Posts 7,729

if you try to store the selected value from you ddl in another variable, you will need to add additional code to get it to survive postbacks.

how about simply adding a readonly property that reads the selectedvalue directly from your inner dropdownlist

    Public ReadOnly Property SelectedValue() As String
        Get
            Return Me.DropDownList1.SelectedValue
        End Get
    End Property

Mike Banavige
~~~~~~~~~~~~
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