.NET Tutorials, Forums, Interview Questions And Answers
Welcome :Guest
Sign In
Win Surprise Gifts!!!

Top 5 Contributors of the Month
Gaurav Pal
Post New Web Links

Strange validation behaviour on dynamically created controls

Posted By:      Posted Date: September 28, 2010    Points: 0   Category :ASP.Net

I'm trying to debug an application which generates a fixed number of questions from a database of 20 questions, and validate them on button click. On postback, I want the incorrect questions to be labeled red. However, all the questions are labeled red on postback. I'm almost positive that the problem is with "page_init" and "page_load",  I'm using session variables to keep track of the question IDs and invalid questions. Any help is appreciated.

Here is the sample code.

Protected Sub Page_Init(ByVal s As Object, ByVal e As EventArgs)
       dim i as integer
       if Not Page.IsPostBack then
           // generates a random integer array for loading the questions
       For i = 0 To 1  // I'm only loading two questions 
              //extract_question queries the database and load the controls dynamically
         end if      
       end if 
    End Sub

Protected Sub Page_Load(ByVal s As Object, ByVal e As EventArgs)
        If page.IsPostBack then
         dim textlabel as string
            dim sessionvar as string
            dim sessionc

View Complete Post

More Related Resource Links

how to apply validation controls on Gridview which is created dynamically

 hi, i created a gridview with two columns and 8 rows dynamically. All the rows are empty and editable at runtime. I am giving column names for this grid from some other .aspx page by passing column names using querystring.Because i am using this grid for three different pairs of column names.  i would like to know how to apply Required Field Validator, Regular Expression Validator  and Range Validator on Gridview textboxes. So that by using those validators i want to validate user inputs. And i would also like to know how to add rows at runtime for this grid. I am using ASP.net 2.0 and C#.net for this.(Visual Studio 2005) The code i am using to create gridview is below. <%@ Page Language="C#" AutoEventWireup="true" CodeFile="LoadData.aspx.cs" Inherits="LoadData" %>  <form id="form1" runat="server">  <div> <asp:GridView ID="GrdDynamic" runat="server" AutoGenerateColumns="False" ForeColor="#333333" BorderColor="GradientInactiveCaption" BorderStyle="Solid" style="z-index: 108; left: 24px; position: absolute; top: 13px">  <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />  <RowStyle BackColor="#EFF3FB"

Adding carriage returns between 2 dynamically created controls in an HtmlTableCell


The title pretty much explains it. Here is what i'm trying to do...

 Private Sub LoadGrid_CommentsField(ByVal Row As HtmlTableRow, ByVal BookingNumber As String, ByVal CommentsText As String)
  Dim Txt As TextBox
  Dim Cmd As ClickOnceButton.ClickOnceButton

  Txt = New TextBox
  Txt.ID = "txtComment_" & BookingNumber
  Txt.CssClass = "TFAppControls"
  Txt.TextMode = TextBoxMode.MultiLine
  Txt.MaxLength = 500
  Txt.Width = New Unit(95, UnitType.Percentage)
  Txt.Text = CommentsText

  Row.Cells(cComments).InnerHtml &= "<br/>"

  Cmd = New ClickOnceButton.ClickOnceButton
  Cmd.DisableAfterClick = True
  Cmd.Text = "Save Comments"
  Cmd.ID = "cmdSaveComments_" & BookingNumber
  Cmd.CssClass = "TFAppButtons"
  Cmd.EnableViewState = False
 End Sub

On the line where i try and update the InnerHtml, i get the following error; "Cannot get inner content of  because the contents are not literal."

Retrieve Dynamically Created Controls

I am building a webform dynamically but when I go to get the values the placeholder has no controls.  Every control added has an unique ID.  Does anyone know what I am doing wrong (language is C#).      aspx page <asp:UpdatePanel ID="upShoppingCart" runat="server" UpdateMode="Conditional" >                    <ContentTemplate>                        <asp:PlaceHolder ID="phShoppingCart" runat="server" />                        <br /><asp:Button ID="btnUpdateCart" runat="server" Text="Update" OnClick="btnUpdateCart_OnClick" />                    </ContentTemplate>                </asp:UpdatePanel>   .cs page         private void CreateShoppingCart()     &nb

Dynamically created controls not accessible after post back.

Dear Friends, pls give the solution. code given below.. dynamically HtmlInputCheckBox created and add in PlaceHolder(panel). I can't get the created control values after post back..Dynamic Control Creationprivate void GetPhotos() { HtmlImage img; HtmlInputCheckBox ic; panel.Controls.Clear(); DataTable dtPhotos = DLayer.Qry_WithDataTable("ADM_GET_HotelPhotos"); foreach(DataRow drPhotos in dtPhotos.Rows) { if ( File.Exists(Server.MapPath("../Photos/Hotel/" + drPhotos["FileName"].ToString()))) { ic = new HtmlInputCheckBox(); ic.Value = drPhotos[0].ToString(); if (drPhotos["PStatus"].ToString() == "1") ic.Checked = true; else ic.Checked = false; panel.Controls.Add(ic); img = new HtmlImage(); img.Src = "~/Photos/Hotel/" + drPhotos["FileName"].ToString(); img.Alt = drPhotos[1].ToString(); img.Attributes.Add("title", drPhotos["PhotoCaption"].ToString()); panel.Controls.Add(img); } } }Get checkbox values foreach (Control ctbl in panel.Controls)        {            if (ctbl is HtmlI

Resize dynamically created controls on Canvas



This is my first thread on this forum and i'm a beginner on WPF.

After google-ing for long time, it seems I can't find a solution for my problem.

I'm working on WPF form. The form contains a canvas and I create Labels on the Canvas dynamically at run-time.

First I had a problem to move the control on the canvas, but eventually I solved this problem by using a class implemented by Josh smith from

his article on codeproject.com. Now, I can move my lables freely on the Canvas.

But now, I want to resize the labels width or height that are created at run-time.

I changed the cursor of the mouse to (horizontal scroll or Vertical scroll) when it touched when of the edges of the label.

but I can't find how to implement the resizing when the mouse goes down or pressed to stretch the label.

Many tutorials found on the web talks about resizing controls the are previously declared in xaml and I want to implement it at code-behind.

Can please help me.

Thanks for help in advance.

jquery how to loop through dynamically created controls


I'm trying to use the following loop to loop through dynamically created controls on my web form:

                for(x = 0; x <= count; x++) {
                    Stmt += $("#DDLColumns" + x).val();
                    switch($("#DDLConditional" + x).val()) {
                        case "is equal": Stmt += " = ";
                        case "begins with": Stmt += " LIKE '%";
                    Stmt += $(&q

How do I determine the size of a dynamically created set of controls?



How do I determine the size of a dynamically created set of controls?

For example, suppose I have a method that creates a form made up of many TextBlocks, TextBoxes, etc., all contained within a grid and that grid is returned by the method.  I need to determine the size of that grid without adding it to any other controls.

    Grid myForm = myMethodThatReturnsAGrid();

    // Here is where I want to find out the size (height and width) of the grid myForm.

The reason I need the size, mainly the height is to determine if it will fit in what is left of the page of a FixedDocument for a report, and if not, to move it to the next page.




Regards, Robert -- Note: I work on various aspects of one or more programs, working on what is most important at the time. Some questions I ask are on aspects of the program that are not important right now or I'm using a workaround for now. Eventually they'll be high priority again and I'll get back to those answers received and respond accordingly. Those that are high priority get responses very soon. Thanks for your input, it is appreciated.

Dynamically Create Controls in ASP.NET by Using Visual C# .NET

This article demonstrates how to dynamically create a control for an .aspx page. The sample project does the following:
Creates two TextBox controls.
Verifies that the contents (TextBox.text) and the attributes of the TextBox are saved across posts to the server.
Illustrates handling events that are posted by a dynamically-created control

Dynamically Create Controls in ASP.NET with Visual Basic .NET

This step-by-step article describes how to dynamically create controls for an ASPX Web page.

The sample project does the following:
It creates two TextBox controls.
It verifies that the TextBox contents (TextBox.text) and attributes are saved across posts to the server.
It describes how events that are posted by a dynamically created control are handled.

ASP.NET: Selectively Enable Form Validation When Using ASP.NET Web Controls


Sometimes the extra controls that come with Visual Studio .NET can be a bit inflexible or they just don't provide enough functionality or flexibility for all situations. The ASP.NET form validation controls, while powerful and easy to use, require that the entire page be valid before it's submitted back to the server. Through the use of the new object-oriented features of Visual Basic .NET, it is possible to extend their functionality to overcome this limitation. This article tells you how and helps you decide when it's a good idea to keep validation on the client and when you'd be better off disabling it.

James M. Venglarik II

MSDN Magazine April 2002

How to dynamically create user controls ?



can you explain how to create user control dynamically in a web form ?When i am creating server controls of user controls are not instantiated and it is not getting initialized .when i am tyying to initialize its properties error occurs tha object instance not created .

Any suggestion ? 

ASP.NET DateTime Conversion strange behaviour



I am working on ASP.NET web application where we are using javascript calendar to accept the date in textboxes. The date format is dd/mm/yyyy. The application is running in US and UK environments.

I am facing issues in US environment while storing the dates so I have added 2 keys in config file viz culture which will be either en-US or en-GB depending on the deployment location and baseCulture which will always be en-GB.

In the code, I have added a condition which checks if culture and baseCulture values are not matching then do the conversion of date in US format.

But I have found that the code converts the date from dd/mm/yyyy to mm/dd/yyyy when the key is baseCulture (en-GB) and it throws FormatException when key is culture (en-US).

I am bit confused by this behaviour. Is this normal? Can any one please explain more about this? Note: I am working on a machine which has en-US as language and culture

<add key="culture" value="en-US" />
<add key="baseCulture" value="en-GB" />
// This line works and converts the date from 26/08/2010 to 08/26/2010
// Here the baseCulture is en-GB.
DateTime dt = DateTime.Parse(txtCurrentDate,baseCulture)

// This line throws FormatException. culture 

Issues with dynamically created TabContainer (Hide/Show TabPanel)


I have a web page that contains an UpdatePanel. In that panel, there is a TabContainer control that has 5 TabPanels, only the first one "Tab 1" will be displayed during initial page load. There is an Add button in "Tab 1", whenever it gets clicked, I will add (show) the next TabPanel (Tab 2, Tab 3, etc., all the way to Tab 5). "Tab 2" thru "Tab 5" contains a Close button that will close (hide) the current tab when clicked.

I'm doing all of these from code behind (dynamically create controls in Page_Init event and re-generate them during postback, track each TabPanel's content in a session variable, etc.), and everything seems to work just fine IF after adding several TabPanels, I remove  them in order (i.e. remove Tab 5 first, then Tab 4, Tab 3, etc.). It will NOT work whenever I try to remove a tab in the middle, then I will get all kinds of strange results.

I've attached the sample codes here for reviewing and testing. Any help is greatly appreciated.


==================== demo.aspx page ====================

<%@ Page

Validation Controls Inside UpdatePanel

Hi All,If you use validation control, the base validator will render script WebForm_OnSubmit() to the page and add form onsubmit "onsubmit="javascript:return WebForm_OnSubmit();". This script is used to fire client side validation event.Now I have a listview inside updatepanel, when click edit button to fire the listview edit mode, the above validation script is just not rendered. How shall I work around with that? I need to customize the client validation event here.Thanks.

VERY strange behaviour of IE7 and 8!

Today is a day where nothing seems to work out as expected.I'm currently making the HTML and Javascript templates for our new Corporate Page.The thing works as expected in Firefox, Opera, Chrome and IE 6, but not in IE 7 and 8!The "thing" is a menu/submenu written by me in javascript.The way it looks in Firefox etc:The way it looks in IE 7 and 8:There is absolutely no explanation for the strange "rounded" edge on the right and the gradient going over it.The background is a semi-transparent optimized PNG without color profiles which shows up gray in IE 6 and transparent in the other browsers - as expected.On my other developer's computer, it shows up perfectly in both IE 7 and 8.What could possibly create this behaviour?----source:<div class="subMenusContainer"> <div class="subMenu" id="aboutUsMenu"> <a href="/Home/AboutAurora">About AURORA</a> <a href="/Home/AboutErichKrammer">Erich Krammer</a> <a href="/Home/AboutFoundation">AURORA Foundation</a> <a href="/Home/AboutPartners">Partners</a> <a href="/Home/AboutCareers">Careers</a> <a href="/Home/AboutContact">Contacts</a> </div> [snip] <div class="subMenu&q

How to I apply an XAML declared animation to multiple controls dynamically?

Hello, How to I apply an XAML declared animation to multiple controls dynamically? Here is the XAML declared animation: <Window.Resources> <Storyboard x:Key="TextBlock_SB"> <DoubleAnimation Storyboard.TargetName="TextBlock_1" Storyboard.TargetProperty="(TextBlock.Opacity)" From="1.0" To="0.75" Duration="0:0:0.5" AutoReverse="True" RepeatBehavior="Forever" /> </Storyboard> Here is the code that starts the animation for TextBlock_1: (this.Resources["TextBlock_SB"] as Storyboard).Begin(); I want to apply the same storyboard/animation to TextBlock_2 and TextBlock_3 and perhaps others.  How do I do that without defining more XAML storyboards? Regards, Robert  

Cannot retrieve values of dynamically generated controls

Hi All, I am creating a user control which contains checkboxes and labels that needs to be created on fly. The dynamic generation of these controls depend on the values retreived from a SPlist. I have several panels that display items queried from the list on the basis of a selection criteria. On a button click event I need to capture all the selected values from the controls that were generated dynamically.  When I traverse each dynamic control that I added to the panel, I dont see their values. I tried using recursive retrieval of the control from the page as well but it just behaves crazy, it treats a radio button as a checkbox and returns a value that I am not looking for. I am not using the the page_load() or any other event, I use the button handler on my custom method. I was thinking for ViewState, ControlsState or SessionState. I assume ViewState may not work on this as the dynamically generated controls need to be in the page_load event. Please guide as this getting way more complicated than what I had ever thought of it to be.
ASP.NetWindows Application  .NET Framework  C#  VB.Net  ADO.Net  
Sql Server  SharePoint  Silverlight  Others  All   

Hall of Fame    Twitter   Terms of Service    Privacy Policy    Contact Us    Archives   Tell A Friend