.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

Dynamic Controls created missing after postback

Posted By:      Posted Date: September 20, 2010    Points: 0   Category :ASP.Net

While generating dynamic controls like , textboxes, dropdownlist, checkboxes and radiobuttons, after filling the textboxes and etc and submit and then postback occurs, the dynamic created controls missing. I try to find a way to make the controls persist for validation checking. Tried to use Viewstate to store the pnlTextBoxes and etc, but it has serializable error.  



protected void Page_Load(object sender, EventArgs e)
            pnlTextBoxes.Visible = false;
            pnlCheckBoxes.Visible = false;
            pnlRadioButtons.Visible = false;
            pnlDropDownList.Visible = false;
            pnlSubmitButton.Visible = false;
            pnlResults.Visible = false;


        protected void btnGenerateForm_Click(object sender, EventArgs e)

            if (tbTextBox.Text != String.Empty)

                if (Convert.ToInt32(tbTextBox.Text) > 0)
                    Label lblTextBox;
                    TextBox tbTextBox1;

                    for (int i = 0; i < Convert.ToInt32(tbTextBox.Text); i++)
                        lblTextBox = new Label();
                        lblTextBox.ID = "lbl" + i;
                        lblTextBox.Text = "TextBox" + i + ":&quo

View Complete Post

More Related Resource Links

Controls missing values after postback


I just uploaded an asp.net webforms site I've been working on to my ISP's servers. I have a simple page that allows users to enter schedule data.  The problem is that when the user clicks the Add button and I try to process the values they've entered in the textboxes and dropdownlist in the click event handler, all the values are blank. For example, there's a DropDownList called uxStartTime on the page and after postback uxStartTime.SelectedValue is blank.  However, the Response.Form[uxStartTime.UniqueID] has the proper value.  I have EnableViewState="true" in the aspx page. This all works fine on my local machine, just not on the server. Can anyone tell me what's going on? I can use the Respons.Form syntax, but it's a little more verbose and prone to typos.

Need help regarding C# / AJAX Dynamic Controls creation


radiobuttons is assigned before page init.. 

public partial class Default : System.Web.UI.Page
//Assign values as a specific Dynamic WebControl Creation.
List<RadioButton> radioButtons = new List<RadioButton>();
List<CheckBox> checkBoxes = new List<CheckBox>();

Then I created a class that would dynamically create a table containing the available flights depending on session.. (See CallPageLoad())

The placeholder and button is inside the UpdatePanel...

on the button inside the update panel, (btnSelect)

i have this code which works... 

protected void btnSelect_Click(object sender, EventArgs e)

Label1.Text = Convert.ToString(radioButtons.Count);

It detects the number of radiobuttons that were dynamically created...

But when I use the following code inside the BtnSelectClick event...

//PLS HELP.......
foreach (RadioButton button in radioButtons)
if (button.Checked == true)
Label1.Text = "You select... " + button;



It does not work even though t

All my server-controls became unrecognized!!! like there's compilation error or web.config missing!



please help - the problem is in post subject.

I have lots of warnings with following text:

"Warning 10 Element 'HyperLink' is not a known element. This can occur if there is a compilation error in the Web site, or the web.config file is missing. C:\Users\Pavel\Documents\Visual Studio 2010\WebSites\BioWebSite\ToScientist.aspx 26 18 C:\...\BioWebSite\" 

But web.confg is there! And there's no compilation error!

Site builds just fine. And If I upload it to my hoster - it works!


But with all these errors I cant add controls to pages - VS2010 adds hyperlink without ID, and intelisens stoped to work.

Strange, but in my other project (web-application) I have no such difficuty.

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."

Problem with Dynamic Controls



I have a custom user control that contains within it a repeater control. Inside this repeater I programmatically add another custom user control, which contains a text box and a custom validator. This final custom user control can be added any number of times depending on the application's logic. All of this is part of a wizard step.

When the user completes the step, if any of the data added to the text boxes is incorrect the validator gets fired on post back. However, because I can have any number of these controls added to the repeater, the user has to scroll down to see any of the incorrectly completed boxes.

Due to the controls being added dynamically it is not possible to use a validation summary control - I have tried!!! Therefore, is there away I can use JavaScript to position a cursor or to jump to each incorrectly completed textbox without the user needing to scroll down the page? For example, if there are 10 textboxes, and textboxes 8 and 9 have numbers inside them inside strings, then the JavaScript should jump textbox 9.

dynamic creating controls in webpart


Hello everybody,


My webpart (wss 3.0, VS2005) initialy contain a listbox. Depeding on the selection made a certain amount of textboxes are to be created and rendered. Via these dynamically created / rendered textboxes text can be submitted (via a button), for futher processing.


I am not sure how, or where in the webpart code, to dynamically create these textboxes.


Maybe somebody can give me some advise on this topic.


Thanks in advance









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"

add any number of dynamic controls on press of button

how can i add new control like image on every click of a button. the number of controls added should be number of times i pressed that button

Get content of programatically created control before postback

Hi.I have quite a problem here, and hope you can help :)I´ll try to describe the problem in steps, as this might be the easiest to understand:1. Page_Load is called when the page is requested, and calls a BuildTable() method2. The BuildTable method creates a table which contains several textboxes3. the user types some text in these textboxes4. The userthen  changes an item in a Dropdownlist on the page which is intended to change some other content on the page5. Page_Load is called, and afterwards the DropDownListBookingType_SelectedIndexChanged(object sender,EventArgs e) method are called, and the content is changed6. The text the user typed in the programmatically created textbox controls are lost!Now how do I remain this text information? If just the SelectedIndex_changed method was called first, I could save it in session.. But as far as I can tell, all data on the page are discarded when you create a partial postback :(What to do?Thanks alot for your time!

Custom panel - missing design time support for controls.

I’m trying to implement a custom panel, one that will behave kind of like the standard Canvas panel. The implementation is done and it is working when I add components in the xaml, but what is not working is move and resize of components in the designer. In the designer each component shows the ‘selected frame’ when selected, but it cannot be moved or resized. Can someone point me to what I’m missing, or an article that describes how do add this support?.   The reason I’m not deriving from the existing Canvas is mainly because I want to understand how it works and how to implement it manually.   Thanks  

Dynamic controls

i want to generate button dynamically and i want to select the dimension and onclick event for that

Problem with Dynamic Controls inside an UpdatePanel

Hello Everybody ,I have this problem,if anyone could help me i'll be so gratefull. I had been created some dynamic radio buttons in a loop inside a dinamy table which is inside an UpdatePanel , but i can not handle the events my code is below:public void MetodoCreacion(){RadioButton RBtn = null;Table table = new Table();TableRow row = null;TableCell cell = null;for (int i = 0; i < 5; i++){row = new TableRow();cell = new TableCell();RBtn = new RadioButton();RBtn.ID = "RBGN_" + i.ToString();RBtn.GroupName = "RBGN1";RBtn.Text = "Opcion " + i.ToString();RBtn.CheckedChanged += new EventHandler(RBtn_CheckedChanged);RBtn.AutoPostBack = true;cell.Controls.Add(RBtn);row.Controls.Add(cell);table.Controls.Add(row);}UpdatePanel1_UpdatePanelAnimationExtender.Controls .Add(table);}public void RBtn_CheckedChanged (object sender, EventArgs e){Label1.Text = ((RadioButton)sender).ID;}and the controls doesent call the event ...thanks a lot

Validation on detailsview that contains both dynamic and standard controls?

I have a form that, originally, contained only dynamic controls. Validation worked perfectly, all in one spot.Today I changed three of the controls to cascading dropdown lists, two of them being required fields.After adding a RequiredFieldValidator for the two required fields, it's as though I have two separate validation events:1. Dynamic field validation - any errors show up in validation summary, and after all are resolved, no longer appear2. Required field validation - do not appear in validation summary until after all dynamic fields are validatedA user could press submit, and be alerted of one or more validation errors from the dynamic fields. Then, after resolving all those, the user would THEN see the RequiredFieldValidator messages in the validation summary. That would be understandably frustrating.Aside from using non-dynamic validation & RequiredFieldValidator for each field ... is there any way to have one validation sequence?Hope this makes sense.Thank you!

Dynamic list item title based on date created & regional settings?

I have a list of things that doesn't *need* a title.  However, because sharepoint uses Title for links, RSS etc  I tried generating a title in an event handler.   This would work great if I wasn't basing it on a date field: public override void ItemAdding(SPItemEventProperties properties) { DateTime dt = Convert.ToDateTime(properties.AfterProperties["TestDate"]); properties.AfterProperties["Title"] = dt.ToShortDateString(); base.ItemAdding(properties); } In testing, this sets the title to "8/9/2010" when I selected 8/10/2010 in the date picker.  I figure this is because of the regional settings of my test user.  I can probably correct the title value for 'test user' but that won't fix 'test user in mongolia' who would still see two different values. So What I would like is to have the Title always display the value MyDate in the uesr's locale.  So the field needs to be dynamic not only at edit/update time, but at display time. Does anybody know if this can be accomplished, and more specifically how?

Need Help : Dynamic ASP.net controls

Hello,I have a calendar control and am dynamically adding textboxes to each cell for each day.Each day has some value assigned to it.It's an asp text box. I'm just using e.Cells.Add(textbox).user fills in some values for each day and then wants to save data.How do i get a handle to each text box.I want to iterate through the text boxes and get the data for each day and then save it in the database.Want to specifically used any features that .net provides i.e. accessing values of dynamically ceated controls.Thanks...

1st PostBack only: SelectedIndexChanged events fire AND GridView & ReadOnly controls disappear

On initial load of the page, everything is visible & runs correct. On the first PostBack fired by any one of my DDLs, RadioBtns, LinkBtns that have the AutoPostBack=true property, then ddlPriority_SelectedIndexChanged & ddlPendUserReqType_SelectedIndexChanged events always fire (and only from these DDLs, the others don't fire inappropriately), even when neither of those controls had been selected. Then my GridView gridPendRoles disappears, unless a DataSource & DataBind() is forced. Any ReadOnly controls (lblTicketID, txbxInsertTicketDate, lblPendUserID) will also loose their data/text in the first PostBack. However, every PostBack following will not inappropriately fire events. And as long as a DataSource was set & DataBind() called a 2nd time at any time during any PostBack, the GridView will stay visible with correct data displayed. Again, as long as the ReadOnly controls have their data/text set a 2nd time during any PostBack, they too will retain their data/text for every following PostBack. I've tried debugging with Trace on & walked thru everything very thoroughly, but still cannot catch any reasons why this would occur. And since I am using the Delete & Edit command linkBtns in my GridView, I can't just force a DataSource & DataBind() on every PostBack, or I would loose those Row

JQuery with dynamic ASP.NET controls (DropDownList)

I am mixing JQuery with ASP.NET webforms.  Adding dynamic controls and accessing the selected values with JQuery works differently under different circumstances and I am trying to establish the difference. Why does Senario 1 work in debug mode but not without breakpoints?  What does databinding to a GridView do that adding DropDownList controls to a asp:panel does not? Is there some sort of DOM registration going on in DataBind? All senarios use the same JQuery: var ddlCollection = $("select[name$='ddlDynamicDropDown']") Senario 1: Breakpoints on each line (Success) Add DropDownList controls to a asp:panel dynamically in the PageLoad method (Does the page lifecycle matter? OnLoad method instead?). Run the code Select values and click on a button firing a JavaScript function (Break in Debug) Break in JavaScript file Access the dropdowns and their selected values successfully Senario 2:  Run the Senario 1 code without breakpoints (Fails to locate the ddlCollection) Senario 3: Use a GridView (Success) Add values to populate the DropDownList controls to a Generic List. Bind the values to a GridView control containing the DropDownList controls Run the code Select values and click on a button firing a JavaScript function Use JQuery to Access the dropdowns and their selected values successfully.  
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