Well I have a strange problem.
I have a page with 2 DropDownLists on it and a custom web-user-control. The custom web user control has an UpdatePanel within it, and an Ajax Timer control within the UpdatePanel to periodically update a listing of stuff.
When I "drop-down" one of the DropDownLists and hover over (not click on) an option while the Timer control within the UpdatePanel asynchronously posts back to the server, the DropDownList "autopostbacks" to the server!
I'm trying to figure out why an asynchronous postback would cause the DropDownList to act as if I selected/clicked on an option so that I can find a way around this issue.
Now it's really simple to reproduce this problem.
Create a Web User control called "TimerUpdatedListing"...this is the ASPX code markup for the web user control:
<%# Control Language="vb" AutoEventWireup="false" CodeBehind="TimerUpdatedListing.ascx.vb" Inherits="MyNamespace.TimerUpdatedListing" %>
<div style="width: 150px; height: 150px; overflow: auto; border: solid 1px navy;">
<asp:UpdatePanel ID="anUpdatePanel" runat="server">
<ContentTemplate>
<asp:Repeater ID="aRepeater" runat="server">
<ItemTemplate>
<div style="border-bottom: solid 1px #EEC900; margin: 3px; padding: 2px;">
Id:
<%#Eval("Id")%>
<br />
Time:
<%#Eval("Time")%>
</div>
</ItemTemplate>
</asp:Repeater>
<asp:Timer ID="aTimer" runat="server" Interval="2000">
</asp:Timer>
</ContentTemplate>
</asp:UpdatePanel>
</div>
This is the VB.NET server side code for the web user control:
Public Partial Class TimerUpdatedListing
Inherits System.Web.UI.UserControl
Private _aListOFThings As List(Of Things)
Private Sub aTimer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles aTimer.Tick
If Session("_aListOfThings") Is Nothing Then
_aListOFThings = New List(Of Things)
Else
_aListOFThings = CType(Session("_aListOfThings"), List(Of Things))
End If
If _aListOFThings.Count > 9 Then
_aListOFThings = New List(Of Things)
End If
_aListOFThings.Add(New Things((_aListOFThings.Count + 1).ToString, Now.ToString("hh:mm:ss")))
Session("_aListOfThings") = _aListOFThings
aRepeater.DataSource = _aListOFThings
aRepeater.DataBind()
End Sub
Private Class Things
Private _time As String
Private _id As String
Public Property Time() As String
Get
Return _time
End Get
Set(ByVal value As String)
_time = value
End Set
End Property
Public Property ID() As String
Get
Return _id
End Get
Set(ByVal value As String)
_id = value
End Set
End Property
Public Sub New(ByVal id As String, ByVal time As String)
_id = id
_time = time
End Sub
End Class
End Class
Now, in an ASPX page called WebForm1.aspx, add 2 DropDownLists and the web user control:
<%# Page Language="vb" AutoEventWireup="false" CodeBehind="WebForm1.aspx.vb" Inherits="MyNamespace.WebForm1" %>
<%# Register Src="TimerUpdatedListing.ascx" TagName="TimerUpdatedListing" TagPrefix="uc1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Test</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true">
<asp:ListItem Text="1" Value="1" />
<asp:ListItem Text="2" Value="2" />
<asp:ListItem Text="3" Value="3" />
<asp:ListItem Text="4" Value="4" />
<asp:ListItem Text="5" Value="5" />
</asp:DropDownList>
<asp:Label ID="selectedValue1" runat="server"></asp:Label>
<br />
<asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="true">
<asp:ListItem Text="a" Value="a" />
<asp:ListItem Text="b" Value="b" />
<asp:ListItem Text="c" Value="c" />
<asp:ListItem Text="d" Value="d" />
<asp:ListItem Text="e" Value="e" />
</asp:DropDownList>
<asp:Label ID="selectedValue2" runat="server"></asp:Label>
<br />
<br />
<uc1:TimerUpdatedListing ID="TimerUpdatedListing1" runat="server" />
</div>
</form>
</body>
</html>
Here is the VB.NET server side code for the WebForm1.aspx page:
Public Partial Class WebForm1
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If String.IsNullOrEmpty(Request.Params("ddl1")) = False Then
selectedValue1.Text = Request.Params("ddl1")
End If
If String.IsNullOrEmpty(Request.Params("ddl2")) = False Then
selectedValue2.Text = Request.Params("ddl2")
End If
End Sub
Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
Response.Redirect(Request.Url.LocalPath + "?ddl1=" + DropDownList1.SelectedValue.ToString, True)
End Sub
Private Sub DropDownList2_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList2.SelectedIndexChanged
Response.Redirect(Request.Url.LocalPath + "?ddl2=" + DropDownList2.SelectedValue.ToString, True)
End Sub
End Class
Thanks,
-Frinny
Here is an example of using triggers to trigger your update panel. Put the timer.tick event as a trigger and see what happens
http://www.asp.net/ajax/tutorials/understanding-asp-net-ajax-updatepanel-triggers
PS: I don't think the timer has to be included within the update panel. I actually build my timers in the codebehind and keep them out of the markup all together.
I attempted two different solutions to this problem.
The first thing I did was to check the Request.Params("__EVENTTARGET") to see if it matched the DropDownList. If it matched then I would call the Response.Redirect() method.
For example:
Public Partial Class WebForm1
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If String.IsNullOrEmpty(Request.Params("ddl1")) = False Then
selectedValue1.Text = Request.Params("ddl1")
End If
If String.IsNullOrEmpty(Request.Params("ddl2")) = False Then
selectedValue2.Text = Request.Params("ddl2")
End If
End Sub
Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
Dim ctrlNameThatCausedPostback As String = Request.Params("__EVENTTARGET")
If String.IsNullOrEmpty(ctrlNameThatCausedPostback) = False AndAlso Page.FindControl(ctrlNameThatCausedPostback) Is DropDownList1 Then
Response.Redirect(Request.Url.LocalPath + "?ddl1=" + DropDownList1.SelectedValue.ToString, True)
End If
End Sub
Private Sub DropDownList2_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList2.SelectedIndexChanged
Dim ctrlNameThatCausedPostback As String = Request.Params("__EVENTTARGET")
If String.IsNullOrEmpty(ctrlNameThatCausedPostback) = False AndAlso Page.FindControl(ctrlNameThatCausedPostback) Is DropDownList2 Then
Response.Redirect(Request.Url.LocalPath + "?ddl2=" + DropDownList2.SelectedValue.ToString, True)
End If
End Sub
End Class
I noticed that this didn't always work. There were times when I selected an option in the DropDownList and the Redirect wouldn't take place because the timer tick and the selected index changed event happened at the same time.
So the second approach I took was to check to see if the page is in an asynchronous postback to the server. If it was, then I knew that it was the timer tick event taking place and that the Redirect shouldn't occur.
For example:
Public Partial Class WebForm1
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If String.IsNullOrEmpty(Request.Params("ddl1")) = False Then
selectedValue1.Text = Request.Params("ddl1")
End If
If String.IsNullOrEmpty(Request.Params("ddl2")) = False Then
selectedValue2.Text = Request.Params("ddl2")
End If
End Sub
Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
If ScriptManager.GetCurrent(Me.Page).IsInAsyncPostBack = False Then
Response.Redirect(Request.Url.LocalPath + "?ddl1=" + DropDownList1.SelectedValue.ToString, True)
End If
End Sub
Private Sub DropDownList2_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList2.SelectedIndexChanged
If ScriptManager.GetCurrent(Me.Page).IsInAsyncPostBack = False Then
Response.Redirect(Request.Url.LocalPath + "?ddl2=" + DropDownList2.SelectedValue.ToString, True)
End If
End Sub
End Class
This helped, and the likelihood that the Redirect would occur properly was better than the previous approach; however, it still isn't 100%.
-Frinny
Related
I've placed some controls in a panels. When the page postback, I'm trying to retrieve the posted values, but only the older value seems to be there.
Protected Sub btnSubmit_Click(sender As Object, e As EventArgs) Handles btnSubmit.Click
Dim _txtFName As TextBox = FindControl("editNamePanel").FindControl("txtFName")
Dim _txtMName As TextBox = FindControl("editNamePanel").FindControl("txtMName")
Dim _txtLName As TextBox = FindControl("editNamePanel").FindControl("txtLName")
End Sub
Even when I hover over the e EventArgs is null. Am I missing something?
EDIT
I'm getting new values when I put the above code in the page load event handler
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Handles Me.Load
If Page.IsPostBack Then
'The above code here ...
End If
End Sub
Thank for helping
In your aspx
<asp:Panel ID="editNamePanel" runat="server">
<asp:TextBox ID="txtFName" runat="server"></asp:TextBox>
<asp:TextBox ID="txtMName" runat="server"></asp:TextBox>
<asp:TextBox ID="txtLName" runat="server"></asp:TextBox>
<asp:Button ID="Button1" runat="server" Text="Button" />
</asp:Panel>
In your code behind
Protected Sub Button1_Click(sender As Object, e As System.EventArgs) Handles Button1.Click
Dim _txtFName As TextBox = txtFName
Dim _txtMName As TextBox = txtMName
Dim _txtLName As TextBox = txtLName
End Sub
so i want to have a button the changes the text of a label when i click it and it says page not available, but when i comment out the update panel it atleast shows up.
<form id="form1" runat="server">
<asp:ScriptManager ID="s1" runat = "server"></asp:ScriptManager>
<div>
<h1>UpDaTe PaNeL tEsT PaGe</h1>
start text : Hello <br />
updated text: World<br />
<hr />
<asp:UpdatePanel ID="p1" runat="server">
<ContentTemplate>
<asp:Button ID="Button1" runat="server" Text="Update" OnClick="updateLabel" Height="29px" Width="110px"/> -->
Text: <asp:Label ID="Label1" runat="server" Text="hello"></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
</div>
</form>
codebehind
Public Class aaaa
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
End Sub
Function updatelabel() As String
Label1.Text = "World"
End Function
End Class
The previous answer is correct. The handler for the Label Click event needs the sender as Object and the e as EventArgs parameters. If you do not put them, your updateLabeL() function will not be a valid match for the event handler.
You can remove the OnClick from the button and Try the classic method of handling events.
So your code will be... ( Sorry I'm posting it via app so it might not be in code view )
Protected Sub ChangeLabel(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Label1.text = "TextGoesHere"
End Sub
I am looking to update one of my DDL's functionality by making it dynamically update so if the user adds more files, the drop down will pick this up.
At present my drop down list is pulling from VB code behind, as shown below:
Public Sub DDL_SelectedIndexChanged(sender As Object, e As EventArgs)
Dim ddl As DropDownList = CType(sender, DropDownList) 'item is already dropdownlist
Dim ctl As TextBox = DirectCast(ddl.NamingContainer.FindControl("eTemplate"), TextBox)
If ddl.SelectedValue = 1 Then
ctl.Text = File.ReadAllText("e:Documents\Visual Studio 2013\Projects\Web\Templates\Down.txt")
ElseIf ddl.SelectedValue = 2 Then
ctl.Text = File.ReadAllText("e:Documents\Visual Studio 2013\Projects\Web\Templates\Up.txt")
Else
ctl.Text = ""
End If
End Sub
At the moment I have hard coded in the functionality for the VB to grab specific .txt files, how can I get this to update dynamically from a folder of .txt files?
Thanks for looking.
Here is some sample code for you. This demo uses an UpdatePanel and a Timer to refresh the DropdownList every 5 seconds.
Add a new aspx file to your Web Application and the following code:
<%# Page Language="VB" AutoEventWireup="false" CodeFile="Demo.aspx.vb" Inherits="Zpk_Test2" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html dir="ltr" xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Asynchronous Update Demo</title>
</head>
<body>
<form id="form1" runat="server">
<asp:ScriptManager runat="server" ID="ScriptManager1" />
<asp:UpdatePanel runat="server" ID="UpdatePanel1">
<ContentTemplate>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true" /><br />
<asp:Timer runat="server" ID="Timer1" Interval="5000" Enabled="true" />
</ContentTemplate>
<Triggers>
<asp:PostBackTrigger ControlID="DropDownList1" />
</Triggers>
</asp:UpdatePanel>
<asp:TextBox ID="TextBox1" runat="server" TextMode="MultiLine" Width="300" Height="250" />
</form>
</body>
</html>
This is the code-behind:
Partial Class Demo
Inherits System.Web.UI.Page
Private Const FolderName As String = "C:\Temp" '<-- replace with your folder name
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
RefreshDropDownList()
OpenSelectedFile()
End If
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
' this event is fired everytime a timer ticks.
' refresh your dropdown list here.
RefreshDropDownList()
End Sub
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
OpenSelectedFile()
End Sub
Private Sub RefreshDropDownList()
Dim currentSelected As String = DropDownList1.SelectedValue
DropDownList1.DataSource = IO.Directory.GetFiles(FolderName, "*.txt").Select(Function(f) IO.Path.GetFileName(f)).ToList
DropDownList1.DataBind()
DropDownList1.SelectedValue = currentSelected
End Sub
Private Sub OpenSelectedFile()
Dim fileName As String = IO.Path.Combine(FolderName, DropDownList1.SelectedValue)
TextBox1.Text = IO.File.ReadAllText(fileName)
End Sub
End Class
I have a page with a ScriptManager, a generic HTML drop-down list (<select>), and an UpdatePanel. The UpdatePanel contains a PlaceHolder (for now). During Page_Load, a number of user controls are added to the PlaceHolder (really, it's several instances of the same user control). The number to add is not known until the page loads, so they do need to be loaded dynamically. The drop-down list is populated with the same number of menu items, and there is javascript on the page also (using jQuery) to show only one of the controls at a time depending on the state of the drop-down list.
Each user control has two buttons that should generate an asynchronous postback, a drop-down list that should generate an asynchronous postback on a change in selected value, and a button that should generate a synchronous postback. If I was not generating the controls dynamically, and if there was only one control, the structure would be something like:
<asp:UpdatePanel ID="myUpdatePanel" runat="server" UpdateMode="Conditional"
ChildrenAsTriggers="false">
<ContentTemplate>
<asp:TextBox ID="textBox1" runat="server" />
<asp:TextBox ID="textBox2" runat="server" />
<asp:Button ID="asyncButton1" runat="server" Text="Button1"
onclick="asyncButton1_Click" />
<asp:DropDownList ID="asyncDropDown" ruant="server" AutoPostBack="true"
OnSelectedIndexChanged="asyncDropDown_SelectedIndexChanged" />
<asp:Button ID="asyncButton2" runat="server" Text="Button2"
OnClick="asyncButton2_Click" />
<asp:Button ID="syncButton" runat="server" Text="SyncButton"
OnClick="syncButton_Click" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="asyncButton1" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="asyncButton2" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="asyncDropDown"
EventName="SelectedIndexChanged" />
<asp:PostBackTrigger ControlID="syncButton" />
</Triggers>
</asp:UpdatePanel>
Of course, all the controls inside the ContentTemplate would actually be part of each user control.
Adding the triggers on the server side does not seem to work because no ControlID seems to help the UpdatePanel find the relevant controls. I can use either the control's ID or the control's UniqueID, and it does not work, and I get an error along the lines of
A control with ID 'ctl00$ContentPlaceHolder1$ctl01$asyncButton1' could not be
found for the trigger in UpdatePanel 'myUpdatePanel'.
So, I wonder if I need to register the triggers in the client instead using ASP.NET Ajax. I found this page that basically explains how. However, I do not know how to get the EventName taken into consideration. The examples I have seen so far have merely been adding button clicks, but I don't know how to handle the SelectedIndexChanged event from the DropDownList.
Any help here? Are there examples out there I have missed? It doesn't help, of course, that the method in the link I gave appears to be "unofficial," so I don't see any MSDN documents on the subject.
Thanks!
My suggestion would be to pull all your controls inclusive this UpdatePanel out of this UpdatePanel into an UserControl. Define events in your usercontrol that are raised when the buttons are clicked or the Dropdown's selected index get changed. Handle these events in your page that holds the Placeholder(in a single UpdatePanel,conditional,without triggers). Call the Update-method of the main update panel manually if you add UserControls.
To clarify what i mean have a look at following example:
Main-page aspx:
<asp:UpdatePanel ID="Upd1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
</ContentTemplate>
</asp:UpdatePanel>
Codebehind:
Private Property UserControlCount() As Int32
Get
If ViewState("UserControlCount") Is Nothing Then
ViewState("UserControlCount") = 1
End If
Return DirectCast(ViewState("UserControlCount"), Int32)
End Get
Set(ByVal value As Int32)
ViewState("UserControlCount") = value
End Set
End Property
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
recreateUserControls()
End Sub
Private Sub recreateUserControls()
For i As Int32 = 1 To Me.UserControlCount
Dim uc As DynamicControls = DirectCast(Me.LoadControl("DynamicControls.ascx"), DynamicControls)
uc.ID = "DynamicControls_" & i
Addhandlers(uc)
Me.PlaceHolder1.Controls.Add(uc)
Next
End Sub
Private Sub Addhandlers(ByVal uc As DynamicControls)
AddHandler uc.asyncButton1Clicked, AddressOf ucAsyncButton1Clicked
AddHandler uc.asyncButton2Clicked, AddressOf ucAsyncButton2Clicked
AddHandler uc.syncButtonClicked, AddressOf ucSyncButtonClicked
AddHandler uc.asyncDropDownSelectedIndexChanged, AddressOf ucAsyncDropDownSelectedIndexChanged
End Sub
Private Sub addUserControl()
Me.UserControlCount += 1
Dim uc As DynamicControls = DirectCast(Me.LoadControl("DynamicControls.ascx"), DynamicControls)
uc.ID = "DynamicControls_" & Me.UserControlCount
Addhandlers(uc)
Me.PlaceHolder1.Controls.Add(uc)
Upd1.Update()
End Sub
Private Sub ucAsyncButton1Clicked(ByVal sender As Object, ByVal e As EventArgs)
'only to demonstrate how to add control dynamically and update the UpdatePanel'
addUserControl()
Me.Upd1.Update()
End Sub
Private Sub ucAsyncButton2Clicked(ByVal sender As Object, ByVal e As EventArgs)
End Sub
Private Sub ucSyncButtonClicked(ByVal sender As Object, ByVal e As EventArgs)
End Sub
Private Sub ucAsyncDropDownSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
End Sub
ascx which holds your controls:
<%# Control Language="vb" AutoEventWireup="false" CodeBehind="DynamicControls.ascx.vb" Inherits="AJAXEnabledWebApplication1.DynamicControls" %>
<%# Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
<asp:UpdatePanel ID="myUpdatePanel" runat="server" UpdateMode="Conditional"
ChildrenAsTriggers="false">
<ContentTemplate>
<asp:TextBox ID="textBox1" runat="server" />
<asp:TextBox ID="textBox2" runat="server" />
<asp:Button ID="asyncButton1" runat="server" Text="Button1" />
<asp:DropDownList ID="asyncDropDown" runat="server" AutoPostBack="true" />
<asp:Button ID="asyncButton2" runat="server" Text="Button2" />
<asp:Button ID="syncButton" runat="server" Text="SyncButton" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="asyncButton1" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="asyncButton2" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="asyncDropDown" EventName="SelectedIndexChanged" />
<asp:PostBackTrigger ControlID="syncButton" />
</Triggers>
</asp:UpdatePanel>
Codebehind of UserControl:
Public Partial Class DynamicControls
Inherits System.Web.UI.UserControl
Public Event asyncButton1Clicked(ByVal sender As Object, ByVal e As System.EventArgs)
Public Event asyncButton2Clicked(ByVal sender As Object, ByVal e As System.EventArgs)
Public Event syncButtonClicked(ByVal sender As Object, ByVal e As System.EventArgs)
Public Event asyncDropDownSelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs)
Private Sub asyncButton1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles asyncButton1.Click
RaiseEvent asyncButton1Clicked(sender, e)
End Sub
Private Sub asyncButton2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles asyncButton2.Click
RaiseEvent asyncButton2Clicked(sender, e)
End Sub
Private Sub syncButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles syncButton.Click
RaiseEvent syncButtonClicked(sender, e)
End Sub
Private Sub asyncDropDown_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles asyncDropDown.SelectedIndexChanged
RaiseEvent asyncDropDownSelectedIndexChanged(sender, e)
End Sub
End Class
On this way you won't have problems with ClientID's.
Addition:
If you need access to the controls of your UserControls in the event-handlers, use one of following two options:
cast the sender's NamingContainer to the userControl's type: Dim uc As DynamicControls = DirectCast(DirectCast(sender, Control).NamingContainer, DynamicControls)
replace all occurences of (ByVal sender As Object, ByVal e As System.EventArgs) with (uc as DynamicControls). On this way the reference of your UserControl is added to the event as parameter and you could access public properties of it from the page, f.e.:
dim txt1 as String = uc.Text1
If you have exposed a property Text1 in the UserControl:
Public Property Text1() As String
Get
Return textBox1.Text
End Get
Set(ByVal value As String)
textBox1.Text = value
End Set
End Property
The second option is the cleanest and most readable way.
Update:
According to your comment: you should place the UpdateProgress in the UserControl inside of the UpdatePanel that gets updated. Remember to set the AssociatedUpdatePanelID correctly. For example:
<asp:UpdatePanel ID="UdpForm" runat="server" UpdateMode="conditional" ChildrenAsTriggers="false" >
<ContentTemplate>
<asp:panel ID="FormPanel" runat="server">
<asp:UpdateProgress ID="UpdateProgress1" DynamicLayout="true" runat="server" AssociatedUpdatePanelID="UdpForm" DisplayAfter="0" >
<ProgressTemplate>
<div class="progress">
<asp:Image ID="ImgProgress1" runat="server" ImageUrl="~/images/ajax-loader-arrows.gif" ToolTip="loading..." /> please wait...
</div>
</ProgressTemplate>
</asp:UpdateProgress>
<asp:FormView ID="FormView1" runat="server" DefaultMode="ReadOnly" >
<ItemTemplate></ItemTemplate>
<EditItemTemplate></EditItemTemplate>
<InsertItemTemplate></InsertItemTemplate>
<EmptyDataTemplate>
</EmptyDataTemplate>
<PagerTemplate >
</PagerTemplate>
</asp:FormView>
</asp:panel>
</contenttemplate>
</asp:UpdatePanel>
<asp:UpdatePanel ID="UpdContent" runat="server" UpdateMode="conditional" ChildrenAsTriggers="false" >
<ContentTemplate>
<asp:Panel ID="PnlMain" runat="server">
<asp:UpdateProgress ID="UpdateProgress2" DynamicLayout="true" runat="server" AssociatedUpdatePanelID="UpdContent" DisplayAfter="0" >
<ProgressTemplate>
<div class="progress">
<asp:Image ID="ImgProgress1" runat="server" ImageUrl="~/images/ajax-loader-arrows.gif" ToolTip="loading..." /> please wait...
</div>
</ProgressTemplate>
</asp:UpdateProgress>
Content
</asp:Panel>
</ContentTemplate>
<Triggers ></Triggers>
</asp:UpdatePanel>
I am trying to figure out how to declaratively pass in a event handler into
a user control, but I am stumped. All I can make work is the user control's
event handler.. I can't seem to bubble up the caught event into the parent
page. Ideas would be quite welcome. Here is my code:
Default.aspx:
<%# Page Language="VB" %>
<%# Register TagPrefix="rpt" TagName="filter" Src="WebUserControl.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Test Controls</title>
</head>
<body>
<form id="form1" runat="server">
<rpt:filter ID="DataView1Filters" runat="server" SelectedIndexChanged="DropDown_SelectedIndexChanged" />
<asp:Label ID="Label1" runat="server" />
</form>
<script runat="server">
Public Sub DropDown_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
Label1.Text = String.Format("Inside declarative event handler. {0}<br>", Label1.Text)
End Sub
</script>
</body>
</html>
WebUserControl.ascx:
<%# Control Language="VB" ClassName="WebUserControlTest" %>
<asp:Panel ID="TestPanel" runat="server"></asp:Panel>
<script runat="server">
Private AllEvents As New System.ComponentModel.EventHandlerList
Public Custom Event SelectedIndexChanged As EventHandler
AddHandler(ByVal value As EventHandler)
AllEvents.AddHandler("SelectedIndexChanged", value)
End AddHandler
RemoveHandler(ByVal value As EventHandler)
AllEvents.RemoveHandler("SelectedIndexChanged", value)
End RemoveHandler
RaiseEvent(ByVal sender As Object, ByVal e As System.EventArgs)
Dim value As EventHandler = CType(AllEvents("SelectedIndexChanged"), EventHandler)
If Not value Is Nothing Then
value.Invoke(sender, e)
End If
End RaiseEvent
End Event
Private Sub _SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
Dim ctrl As DropDownList = Me.FindControl("TestDropDownList")
If Not ctrl Is Nothing Then
Me.ViewState("ItemSelection") = ctrl.SelectedIndex
End If
Dim Label1 As Label = Parent.FindControl("Label1")
Label1.Text = String.Format("Inside user control event handler. {0}<br>", Label1.Text)
RaiseEvent SelectedIndexChanged(sender, e)
End Sub
Private Overloads Sub OnLoad(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
Dim ctrl As New DropDownList
With ctrl
.ID = "TestDropDownList"
.Items.Clear()
.AutoPostBack = True
AddHandler .SelectedIndexChanged, AddressOf _SelectedIndexChanged
.Items.Add(New ListItem("-- Select --", String.Empty))
.Items.Add(New ListItem("Item 1", "1"))
.Items.Add(New ListItem("Item 2", "2"))
If Not Me.ViewState("ItemSelection") Is Nothing Then
.SelectedIndex = CInt(Me.ViewState("ItemSelection"))
Else
.SelectedIndex = 0
End If
End With
TestPanel.Controls.Add(ctrl)
End Sub
</script>
Thanks!
See this previous post:
Handling User Control Events on Containing Page
Edit - added based on your comment
I should have read the question more clearly.
As far as having a UserControl raise an event that the containing page can respond to, I do not believe that this can be done declaratively.
Unless my knowledge is just lacking, the only way to accomplish this is by explicitly creating an event in the control and then handling it (by coding the event handler) on the parent page, as shown in the example I linked to.
I was recently having this same issue in C#. When you set up an event called SelectedIndexChanged asp.net will bind the attribute OnSelectedIndexChanged when using the declarative syntax.
So if you change
<rpt:filter ID="DataView1Filters" runat="server" SelectedIndexChanged="DropDown_SelectedIndexChanged" />
To
<rpt:filter ID="DataView1Filters" runat="server" OnSelectedIndexChanged="DropDown_SelectedIndexChanged" />
It should work.