I have been led to believe that the best point to bind your controls is the PreRender. As all the controls are ready and this is the last stage before rendering etc. Is this correct or should controls be bound at a different point?
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Do you know any drawback to add controls to a page on PreRender event?
I am creating Dynamic UserControls with Dynamic AjaxControls. Then I store each of the UserControls in a Collection. On Postback I recall the UserControls in the collection to Re-Create the interface. It works if i only use Standard HTML controls but does NOT work with AJAX controls. I get this error on PostBack Extender controls may not be registered after PreRender. So far I have tried the following:
MyBase.OnPreRender(e) in Page and Usercontrol EnsureChildControls() in the OnInit Added ScriptManager to the MasterPage None of this stuff is working... If I re-create all the controls including the ones inside the usercontrol then i get no error however it takes forever to do a postback as opposed to just recalling the collection of UserControls.
I get this error on postback from using a dynamic created controls, specifically the
Ajax ComboBox. If I use DropDownList instead, then I don't get the error. How to over come this issue? I do need to use theAjax ComboBox because it allow extra properties not available in DropDownListHere is the complete error:Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerServerErrorException: Script controls may not be registered after PreRender.My ToolKitScriptManager resides in the MasterPage.
I am currently trying to use Telerik. I am designing login control. But however I m getting this error :
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I don't know how to resolve it, here is my Code :Aspx :
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And this is C# :
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I have a DetailsView on my page, bounded throught ObjectDS (but I think it's not important). Some field is readonly for some users - based on role membership and other paramaters. I've tried to use the PreRender event to manage these field's readonly state. Everything is working - except one template field: when I click first time on Edit button the dropdown list stay readonly independently the role membership. When I click on Cancel than Edit again the control state is good. Code of PreRender event handler:
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Environment:Web Developer 2008 Express .NET Fw. 3.5 Windows XP
When creating dynamic ajax controls you may experience a pre-render issue on postbacks. You are supposed to re-create the controls on postback, however if there are very many of them performance gets very slow between each postback. i.e. clicking on a combobox, it may take several seconds. So what I did was group the controls in panels, store the panels in a collection, then re-call the panels on Postback. This actually works great if the controls inside the panel are standard html controls (textbox, dropdowlist, etc.). But...doesn't work well with ajax controls...yet.
I have included a sample below. Uncomment/Comment the code to test it.
[Code]....
[Code]....
At the first loading of my page, duration of PreRender takes upto 13 seconds. That page has basically a gridview control which bind to SqlServer query by SqlDataSource. When I execute query seperately, it takes only 0.02 second.
On the other hand, for the next loadings of same page by postback, duration of PreRender varies from 0.5 second to 3-4 seconds.
In addition to gridview, there are several dropdownlist, update panel, ImageButton in gridview. I use paging for Gridview.
Which strategy should i follow to increase performance of this page?
When creating dynamic ajax controls you may experience a pre-render issue on postbacks. You are supposed to re-create the controls on postback, however if there are very many of them performance gets very slow between each postback. i.e. clicking on a combobox, it may take several seconds. So what I did was group the controls in panels, store the panels in a collection, then re-call the panels on Postback. This actually works great if the controls inside the panel are standard html controls (textbox, dropdowlist, etc.). But...doesn't work well with ajax controls...yet.
I have included a sample below. Uncomment/Comment the code to test it. If anyone has a good idea how to make this work with ajax controls that would be great.
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="WebForm1.aspx.vb" Inherits="PreRenderAjax.WebForm1" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
<!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></title>
</head>
<body>
<form id="form1" runat="server">
<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</asp:ToolkitScriptManager>
<div>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
</div>
</form>
</body>
</html>
Public Class WebForm1
Inherits System.Web.UI.Page
Shared panellist As New List(Of Panel)
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If IsPostBack Then
'This is for reloading panels. Works with dropdownlist, but not ajax combobox
For Each pn As Panel In panellist
PlaceHolder1.Controls.Add(pn)
Next
'This for re-creating all the controls again. Not very efficient for ajax controls though.
'CreateInterface()
Else
CreateInterface()
End If
End Sub
Protected Overrides Sub CreateChildControls()
MyBase.CreateChildControls()
End Sub
Protected Overrides Sub OnInit(ByVal e As System.EventArgs)
MyBase.OnInit(e)
EnsureChildControls()
End Sub
Private Sub CreateInterface()
Dim pn As Panel
pn = CreatePanel("panel1")
CreateControls(pn, 5)
pn = CreatePanel("panel2")
CreateControls(pn, 5)
pn = CreatePanel("panel3")
CreateControls(pn, 5)
pn = CreatePanel("panel4")
CreateControls(pn, 5)
End Sub
Private Function CreatePanel(ByVal name As String) As Panel
Dim pn As New Panel
pn.ID = name
pn.Width = 250
pn.BorderStyle = BorderStyle.Solid
pn.BorderColor = Drawing.Color.Blue
pn.Style.Add("margin", "5px")
pn.Style.Add("padding", "5px")
PlaceHolder1.Controls.Add(pn)
panellist.Add(pn)
CreatePanel = pn
End Function
Private Sub CreateControls(ByVal pn As Panel, ByVal howmany As Integer)
Dim cbo As AjaxControlToolkit.ComboBox
'Dim cbo As DropDownList
For i As Integer = 0 To howmany - 1
cbo = New AjaxControlToolkit.ComboBox
'cbo = New DropDownList
cbo.ID = pn.ID & "_cbo" & i
cbo.Width = 200
cbo.Items.Add("Item 1")
cbo.Items.Add("Item 2")
cbo.Items.Add("Item 3")
cbo.Items.Add("Item 4")
cbo.Items.Add("Item 5")
cbo.Style.Add("margin", "3px")
cbo.AutoPostBack = True
pn.Controls.Add(cbo)
Next
End Sub
End Class
Whenever I try to export a ListView with formatting or dynamic content in the PreRender event to an Excel file, I lose all of the changes from the PreRender event. Here's the ListView code:
<asp:ListView ID="ListView1" DataSourceID="profileData" runat="server" DataKeyNames="ROW_NUM">
<LayoutTemplate>
<table cellspacing="0">
<thead>
[Code]....
I've done some reading and found that RenderControl possibly ignores anything in PreRender for a control, but I'm thinking there has to be a way to get those PreRender changes in there before extracting the ListView to Excel.
The only workaround I've found so far is to copy and paste all of my preRender code into the Page_Load, and then everything looks fine in Excel. However, then I have to duplicate my code, as I still need it in the preRender event to display it on the screen properly. I don't want to maintain the code twice.
I have changed the look and feel of the grid by modifying the cols, rows in the gridview. I need to save this in the gridview viewsate, so that it load the modified look and feel next time it loads from the viewsate.
View 3 RepliesI am using ajax tabpanel control. and i have fileupload control, gridview inside the tabpanel.if i select the file in fileupload control and click upload button it has to read the excel file data and bind the gridview.i debugged the code the dataset has the correct values and bind method also calling successfully.
but finaly in the screen shows this error message "Script controls may not be registered before PreRender."
what is the problem.
Getting following error
System.InvalidOperationException: "Script controls may not be registered before PreRender."
On my masterpage i am using Docking Panel control to get collapsable/Expandable left area.
Its working fine but when i try to place an infragistic WebExplorerBar Control inside Docking Panel to get Outlook like view. It gives the above mentioned error.
Following is the code sample.
<xpro:DockingPanel
Text="Navigation" ID="DockingPanelTree" Docking="Left" runat="server"
Direction="RightToLeft"
Interval="0">.........
I read this
[URL]
and I was wondering if there's anyone that can explain to me what Prerender should do, for example for a button or a calendar component.
I can't imagine it; can you show me few lines?
Would a call to a database be called if you put the databind method in the PreRender event of a listbox and the listbox was rendered on the screen for example? This is a specific example regarding a listbox, but basically does code in PreRender only get called if the control is rendered on the screen. If this is so, is it good practice to put code into PreRender such as databinding?
View 1 RepliesI have a SiteMap in my project and I want That on the PreRender The SiteMap appear CollapseAll() but I can't do it.
View 3 RepliesWhen deleting a GridView row in the UI (via a LinkButton whose CommandName="Delete"), the view does not automatically refresh and continues to display the deleted row until I take some other action (manually refresh page, navigate away and back again, etc).
In the debugger, I see the row is successfully deleted, and both the RowDeleting and RowDeleted events fire, but the GridView's PreRender event does not fire afterwards (in contrast, that PreRender event does fire when first loading the page, when adding a new row, etc).
I've used GridViews in similar configurations without having this problem, but I don't see obvious differences. It seems the process is aborting before the PreRender event, but no exceptions are being thrown, and stepping off the end of the RowDeleted event in the debugger brings me back to the UI as though the process were completing normally.
where I should look for the trouble or a solution? Other possibly-relevant details: the GridView is bound to a SqlDataSource; the data source does not declare any DeleteCommand; I handle the deletion by calling a stored procedure in the RowCommand handler, after which I rebind the GridView with DataBind(), at which point I can see the GridView's Rows.Count has decreased by one as I'd expect. Everything seems fine through the RowDeleted event, then... nothing!
UPDATE: tried calling the SP to delete in the RowDeleting handler rather than RowCommand handler... made no difference. The row is still deleted but processing terminates without calling the GridView's PreRender, and the deleted row is left on display until some further UI interaction updates the view.
UPDATE2: I'm not even getting the Page's PreRender event, which precedes the control PreRender events. Will continue working backwards to see if I can find where things are halting, since stepping out of the RowDeleted event seems to be the end of the line...
UPDATE3: I've been poking around some more and, although it complicates my code, I was able to get things working by declaring a DeleteCommand in the GridView's SqlDataSource that just does the simple row (record) deletion, and then in the RowDeleted handler calling the additional stuff I had in my stored procedure that needs to happen along with the primary deletion. While it's less convenient having the primary deletion in one place and the related processing in another, at least it's working.
But I don't know what to conclude from this: that a DeleteCommand is needed for proper page life cycle? that one shouldn't do a deletion in a stored procedure in the RowCommand handler? something else? I wish I could identify what, specifically, is broken about my initial attempt...
I want to access the raw HTML code that my ASP.NET System.Web.UI.Page is about to render.
How can i do that? Is there a property or method like System.Web.UI.Page.HTML or something like that.
I know I could loop through the Controls List of the page and get access to all the Literal Controls etc, but I was wondering if there's a direct property or method that can return me the raw html, which I can modify just before rendering the page.
I have a site with about 7-8 tab panels with update panels. On all the other tabs there doesn't seem to be a problem except the newest tab I created outside of the project and then piece by piece brought on.To make a long story short -
Users selected a dropdownlist outside of the panels and based on what they select certain tabs display.
Both inside the selectedchange of that dropdownlist I have -
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Which just double checks the dropdown since there is a change if the select portion isnt at the top insert it. I also have in the pre-render of that dropdownlist9 the following -
[Code]....
Which is supposed to put the select into the dropdownmenu. But for just this dropdownmenu for reasons beyond me after the first dropdownlist is changed the select statements are not at the top of dropdownlist9. But on the 2nd change and there after they are inserted.
Really running around circles with this. The microsoft visual studio just seems so odd and unrelievable lately.
I need to dynamically modify the contents of a column in a GridView1 before it is displayed. Basically, I need to convert every 'Environment.NewLine' in a field to a so it displays as a new line on an ASP.NET page. How do I do this?
View 2 RepliesIn my gridview I have fields for inserting a new record in the footer.
In my objectdatasource selecting event if no records came back I bind a single mock row to force the footer to show so they can still add records. Since the row does not contain real data I hide the row.
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I have a GridView, here I am adding the LinkButtons at runtime to the GridView cells. I am also attacing an click event on these LinkButtons.
The issue is that when I populate the GridView from the Page_load the LinkButton click works, but if I move GridView polulation code in the Page_PreRender event the click event doesn't executes.
Code:
private void Page_PreRender(object sender, System.EventArgs e)
{
//does not fires the Click event of dynamically generated LinkButtons
GridView1.DataSource = getDataTable();
[Code]....
I am running some custom code in a user control using the <%=Code%> tag. The problem is that the code seems to run before the PreRender event. Is there any way for met to get this code to run after the PreRender event?
View 3 RepliesI have a control on a page. In the control's pre-render event I'm executing some code that's taking about a minute to execute. This means the whole page is unresponsive until the control's pre-render event is finished executing.I tried putting the control inside an update panel, but it doesn't matter the rest of the page still won't render until the pre-render event of the control is finished executing. I've attached a very simple example of my code (The event that's slowing up the control's pre-render event is not Thread.Sleep(1000):
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[Code]....
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Public Class PMRADGrid
Inherits System.Web.UI.GridView
Private Sub PMRADGrid_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
[code]...
