I'm creating an ASP.NET control dynamically based on a value selected in a dropdown; for instance the field can be a textbox or a checkbox (for now), and then it gets added to a placeholder control. However, I'm unsure how to retrieve the value - using the placeholder's FindControl method returns null although I'm specifying the ID when I create the control.
Here's my code:
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Can a placeholder control be created dynamically such that you can add controls to it later on?
PlaceHolder ph_grid = new PlaceHolder();
I add one or more textbox controls to a repeater itemtemplate during OnItemDataBound.
The textbox controls are instantiated and then added to a placeholder.
My problem is getting the user entered values from those dynamically added textboxes. They do not seem to exist in the repeater items collection.
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I am writing a survey generating system in asp.net. i asked an ealier question about the best way to create controls that can be passed about as variables. This was problematic with user controls so i was advised to use custom controls and a quick way to do this was to inherit from the panel control and just add a bunch of standard controls the the controls collection by overriding the CreateChildControls method. This way i could create my "survey" controls,which are basically Questions in the survey. THe question controls are then dynamically added to the page. This all works well but know i have come to the point that i want to try and retrieve the values from these controls and i seem to be lost in a nether world of of viewstates and page lifecycles. I can ensure that the dynamically added text boxes have a known ID, however even if i add the parent control in the page init handler the CreateChildControls method does not run until after until after the viewstate is loaded. I cannot work out how to retreive the values from these text boxes.
View 2 RepliesWhile I am using a "Telerik" control here it shouldn't be any different I guess;
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What happens is that the control is created and rendered;
When I change value in the Combo box a Post-Back happens.
HOWEVER, the event RadComboBoxSelectedIndexChanged does not fire. Also when I am back at the page the new value is not saved; Obviously, i recreate the control every time. If I don't I get a ViewState error. Seems to me that there some ViewState management problem, but I cannot identify it...
I have a user control say SearchVendor.ascx which contains 4 buttons a gridview and another user control. I need to load the control dynamically actually as a modal pop up
I get this code
var uc = Page.LoadControl("~/blah/VendorProductSearch.ascx") as VPSearch;
uc.ShowVPSearch(true);
_tempPlaceHolder.Controls.Add(uc);
it works fine the control gets loaded properly but onclick of any button the second time the control disappears ?
I want the dynamically added control to remain until the user clicks on the cancel button
How can I get the placement of dynamically added control in any page event.
View 6 RepliesI have a control that handles commenting. In this control, I have set a delegate event handler for sending an email.
I then have various types of controls, e.g. blog, articles etc, each of which may or may not have the commenting control added (which is done dynamically with me not knowing the id's), i.e. the commenting control is added outside this control. Each of these controls handles it's emailing differently(hence the event).
What I'm trying to determine, is how to assign the event in the parent control. At the moment, I'm having to recursively search through all the controls on the page until I find the comment control, and set it that way. Example below explains:
COMMENTING CONTROL
public delegate void Commenting_OnSendEmail();
public partial class Commenting : UserControl
{
public Commenting_OnSendEmail OnComment_SendEmail();
private void Page_Load(object sender, EventArgs e)
{
if(OnComment_SendEmail != null)
{
OnComment_SendEmail();
}
}
}
PARENT CONTROL
public partial class Blog : UserControl
{
private void Page_Load(object sender, EventArgs e)
{
Commenting comControl = (Commenting)this.FindControl<Commenting>(this);
if(comControl != null)
{
comCtrol.OnComment_SendEmail += new Commenting_OnSendMail(Blog_Comment_OnSendEmail);
}
}
}
EDIT:
The reason I ask is that if I search from this.Page as the initial control, I am worried about time taken to search down the control tree to find it. Each different type of page would be different in how many control it would have. On some testing, it returns back quite quickly the result.
I have a gridview that on it's RowDataBound event I dynamically add Image Controls to some columns.
The problem is that I lose these images on the next PostBack.
OBS: The GridView's EnableViewState propertie is already set to true
I know about the page lifecycle, but how can I persist these images if I have to add them on the RowDataBound event?
In addittion, if I add a static TemplateColumn with an Image Control and I set it's ImageUrl propertie inside the RowDataBound event it will obviously persist between postbacks. The problem is that I don't know how many columns with images I'll have, it's defined on the datasource.
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I have a dropdown on page, a place holder and a save button on my form.Now, I am creating a textbox on selectedIndexChanged event of dropdown list and adding it to placeholder. And on button click I want to access the control, but on click event, I find the textbox as null. Here is my code
protected void Dropdownlist1_SelectedIndexChanged(object sender, EventArgs e)
{
if (Dropdownlist1.SelectedValue != string.Empty)
And button Save click event
protected void btnSave_Click(object sender, EventArgs e)
{
TextBox txt = new TextBox();
txt = (TextBox)this.ElementPlaceHolder.FindControl("txtArea");
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Need accessing the rendered content of a PLACEHOLDER control. I dynamically add a web forms page to a placeholder using "TABLE" this works great (cell row table placeholder ) now I wish to take that placeholder and use the rendered page to generate a PDF document.
If it possible to access the rendered code how would this be done?
I have a Placeholder control on Employee Main Menu. Several SQL Data sources are run at page load in order to notify employees that something is due. Each "something is due" message is loaded into a unique label. Therefore the Placeholder could have several labels in them. For clarity's sake I'd like them separated by line breaks. However I understand from reading a previous forum item that "< /br>" are ignored. How can I embed a line break when PlaceHolder_Msg.Controls.Count > 1
View 2 Repliesi have one html table "table "and added controls it at run time as :
HtmlTableRow tabelrow = new HtmlTableRow();
HtmlTableCell tablecell = new HtmlTableCell();
Label lbl = new Label();
tablecell.Controls.Add(lbl);
then i want to get each controls by using foreach
such as (foreach control c in table.controls) or (foreach control c in tablecell.controls)but its not working.
I dymamically add checkBoxList to the page. How can I get checked items from it without adding it again?
View 7 RepliesHow can I add the dynamically added control to validation?
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the client-side validations kicks-in. Is there a way to explicitly include the deferredly-created inputs to validations?
i have code to get values from textboxes that were added in placeholder on fly at run time
Code:
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I have a Placeholder in which I added a Hyperlink (the hyperlink is an attachment in messaging application) how do I get the hyperlink to go hot when the user put there mouse over it:
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I know that if I re-add the control during Page_Load, the posted values will be repopulated when the page is rendered; however, this is not the case when re-adding the control during the Click event and I need to add the control during an event handler.
I've got a custom ASP.Net web user control I've built; done this enough times before but this one is misbehaving and I can't spot why.
Where the calling page includes the user control directly in its markup, all is well and the control behaves as expected.
However if the page adds this particular control dynamically (to a placeholder in the master page, which is what's calling this whole thing) the elements within it stay firmly NULL - nothing from the user control gets written to the client at all, including static content within the user control.
I have a GridView of thumbnail photos within an UpdatePanel, with clickable icons in each row which each load a User Control containing a small Google Map into the relevant row. The idea is that the user can geotag (by clicking on the map) any photo in the GridView.
In the map User Control, there is some Javascript initialising the map:
function initializeMap() {
if (GBrowserIsCompatible()) {
var map = new GMap2(document.getElementById('Map'), {size: new
GSize(336, 200)});
// set the map controls, set the centre, etc.
}
}
Problem is: I don't know how to call the initializeMap() method. Because it's dynamically added to the page, any attempt to link it to the calling button by "onClientClick=initializeMap()" for example, gives a JS error, saying the method isn't defined.
I've tried
ClientScript.RegisterStartupScript(this.GetType(), "initializeMap", "<script type="text/javascript">alert('Here'); initializeMap();</script>");
but I don't think I'm on the right track with that one either.
I have an asp page "A" and I've created a user control "B"
When I do A.Controls.Add(B), I would like to make an element, say a TableRow which is defined inside control "B", invisible via code behind.
When looking through Controls of "A", I cannot seem to find that table row.
I'm adding controls from code behind but I dont know how to add an event for each control
X below is from the for loop
Code behind
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What I would like to do is to access libServiceActions CommandArgument in code behind to set db tabel with the values thats passed.
I have a formview that has several dropdownlists in the EditItemTemplate. Some of the dropdownlists are added using placeholders. I can add and populate their listitems without any problem. But when I update the record, none of the controls can be found--even though when I look at the page source they are there. I first strated out using asp:ControlParameter in my sqldatasource updateparameters, but even referencing the control as myform$mycontrol did nothing. So then I moved to code behind on the sqldatasource.updating event (code is attached). The only controls I cannot seem to bind to the update are those added via the placeholder.
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The item at the dim statement is not an item added using a placeholder and does not get a null reference exception (I used that to prove during debbugging that I wasn't losing my mind)--however, all the items being used to get the parameter values are getting null reference exceptions and are added via placeholders. Here is the code I'm using to set up the dropdownlists:
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how to get the value of these controls so they can be used in my update?
I am currently working on a asp.net page coded via Visual Basic.On the page I have these image buttons that are dynamically generated based on the SQL Data the page retrieves.Unfortunately I could not figure out how to bind a click function to each of these buttons.
the [Control Name].onClick = "Function Name()" is for clientSide scripts.and I need to bind
Protected Sub Button_InsertNewTextBox_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button_InsertNewTextBox.Click to the dynamically allocated buttons.
I have a composite user control consisting of three standard table cells (a legend, an image with a tool tip, and a text field control). If I add these to a TableRow in my aspx page it works fine and produces legal HTML in my source. The below works fine ...
<tr><MyControl:dataField
ID="txtEmail"
DataType="Email"
runat="server"
/></tr>
However when I try to do the same programmatically (C#) the TableRow won't accept anything in its Controls collection that isn't a TableCell. I could make my control a nested table in its own right but I lose the alignment of my form items on the page with multiple controls, as each table aligns itself according to its contents. Is there anyway I can make the TableRow accept my control as collection of cells or do I need to do some casting or making my user control inherit some kind of TableCell attributes? I can also dynamically add my controls to a TableCell item which actually displays OK in IE but creates illegal HTML (<td><td></td><td> ... </td></td> - I assume this is illegal) in my resulting source. The code below DOES NOT work ...
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