Develop Reference

Dynamic ModalPopupExtender not firing the OK Click event

ASP.NET 4.7.2 Web Forms c# VS 2019
I am trying to use a modalpopupextender to prompt for new data for foreign key fields. Like the form itself, the MPE is built on the fly in code -- in this case the click handler for the hidden button that the Javascript fires off to build and show the MPE.
I read every single article on SO and the ASP forums and tried everything I saw there. No joy. I get the popup perfectly. Hitting OK closes the popup, but never fires the OK Event.
Here is the code:
//Building the form, we do this in OnInit:
// AJAX Update Panel
UpdatePanel PUP = new UpdatePanel()
{
ID = "PUP",
};
PlaceHolder.Controls.Add(PUP);
// HiddenField containing the field name to permit
// creating the correct modalpopup.
HiddenField HFPopupField = new HiddenField()
{
ID = "HF_POPUP"
};
PUP.ContentTemplateContainer.Controls.Add(HFPopupField);
// Create Hidden button to track the popup
Button BPopup = new Button()
{
ID = "BPOPUP",
UseSubmitBehavior = false
};
BPopup.Click += BPopup_Click;
BPopup.Attributes.Add("style", "display: none;");
PUP.ContentTemplateContainer.Controls.Add(BPopup);
// And create the background panel for the popup.
Panel PnlPopup = new Panel()
{
ID = "PNLPOPUP",
CssClass = "MpeBackground"
};
PnlPopup.Attributes.Add("style", "display: none;");
PUP.ContentTemplateContainer.Controls.Add(PnlPopup);
/// Event handler for hidden button.
protected void BPopup_Click(object sender, EventArgs e)
{
[snip -- code to get the dataset that is being filled]
UpdatePanel PUP = Placeholder.FindControlRecursive("PUP");
Table T = new Table()
{
CssClass = "PopupTbl"
};
TableRow TRTitle = new TableRow();
TableCell TCTitle = new TableCell()
{
CssClass = "PopupTitle",
ColumnSpan = 2
};
Label LPopTitle = new Label()
{
Text = [title of the popup]
};
TCTitle.Controls.Add(LPopTitle);
TRTitle.Cells.Add(TCTitle);
DataRow drData = null;
// Add Fields, and also the cancel and Add buttons
foreach (DataColumn DC in dsColumns.Tables[0].Columns)
{
TableRow TRColumn = [create a tablerow with 2 columns, a prompt and the input field]
if (TRColumn != null)
{
T.Rows.Add(TRColumn);
[snip]
}
} // end of foreach(DataColumn DC in dsColumns.Tables[0].Columns)
PnlWindow.Controls.Add(T);
TableRow TRButtons = new TableRow();
TableCell TCButtons = new TableCell()
{
ColumnSpan = 2,
CssClass="PopupButtons"
};
Button MPEBOK = new Button()
{
ID = "MPE" + sFieldName + "_MPEBOK",
Text = "OK",
CausesValidation = false,
UseSubmitBehavior = false
};
MPEBOK.Click += MPEBOK_Clicked;
TCButtons.Controls.Add(MPEBOK);
LiteralControl LCB = new LiteralControl()
{
Text = " "
};
TCButtons.Controls.Add(LCB);
//************************************************************
//*** Postback Trigger ***
//************************************************************
AsyncPostBackTrigger trigger = new AsyncPostBackTrigger()
{
ControlID = MPEBOK.ID,
EventName = "click"
};
PUP.Triggers.Add(trigger);
//************************************************************
//*** Cancel Button ***
//************************************************************
Button MPEBuhBye = new Button()
{
ID = "MPE" + sFieldName + "_BUHBYE",
Text = "Cancel",
UseSubmitBehavior = false
};
TCButtons.Controls.Add(MPEBuhBye);
TRButtons.Cells.Add(TCButtons);
T.Rows.Add(TRButtons);
PnlPopup.Controls.Add(PnlWindow);
AjaxControlToolkit.ModalPopupExtender MPE = new AjaxControlToolkit.ModalPopupExtender()
{
ID = "MPE" + sFieldName,
PopupControlID = "PNLPOPUP",
TargetControlID = "BPOPUP",
BackgroundCssClass = "MpeBackground"
};
// Add the MPE to the UpdatePanel.
PUP.ContentTemplateContainer.Controls.Add(MPE);
// Show the modal popup extender.
MPE.Show();
}
protected void MPEBOK_Clicked(object sender, EventArgs e)
{
[snip - this never fires]
}
I cannot find out what is happening here. Can anyone see something hinky?
Thanks
John.

You can't add a server side button or inject a server side button into the page DOM.
When you drag a asp.net button onto the form, BOTH the "mypage.cs" and mypage.desinger.cs ARE updated. The wire up of the button occurs at design time, and you would have to modify mypage.desinger.cs ALSO and ADD a button event stub.
So you can't do this.
A compromise would be to also add some js and have that HTML button execute a .click() method of a hidden asp.net button you drop into that page (that would give you the post back, and the running behind of a separate button event code stub.
This event resolution occurs at compile time - not at page render time. You have to drop that button onto the page.
I suppose you could adopt a standard that you always place right below that "div" on the page the button (hidden with style=none. And then as noted, have your injected code along with some js execute a click on the hidden button. Or just have the js button code execute a __doPostback("some value") and pick this up in the page on-load event, and then call the routine (function) from on-page load event.
I think better would be to use a jQuery.UI dialog, as that dialog CAN say load + use another different web page into a “div” on the existing page. So you layout, make, and create the nice looking popup form as a separate web page. jQuery is able to remove the “form” and additonal tags out of that page load, and then inject it into the existing page. (that code would be rather hard to re-produce). so jQuery.UI is able to pop up that separate page. however, the buttons on that loaded page (into that div) of course can't really run any code behind in the current page. However, the buttons CAN run local js in the current page. Thus the actions of this injected page would be local to each page. But the popup would not be directly calling a code behind stub.
Now, to adopt jQuery.UI, then you also have to of course adopt jQuery. So that is two extra libraries you need. (but, jQuery you likely already have).
However, I suppose the whole point of using the ajax toolkit is to avoid jQuery.ui in the first place. To be fair, before jQuery.ui came along, that tool kit was REALLY impressive, and gave asp.net folks a REAL leg up on the competition. (and it tends to be MUCH less wiring up then say using jQuery.UI
So the AjaxToolkit in its heyday was impressive. Now, it of course showing its age, but I still use the kit, and this is especially the case for the AjaxFileUploader. And yes I do use the popups – even to this day. However, I find now that jQuery.UI dialogs are more flexible, and would be better in this case (because you want a on-the fly setup).
Also, having code behind buttons in even the jQuery.UI dialog, or in this case the ajax popup? Well, only the action button can run code behind. The cancel button of course will just dismiss the dialog. However, any button in the dialog that WILL run code behind? Well, that's ok, since you have a page post back, and it actually the page postback that BLOWS out the dialog anyway.

html input button server click event not fire

I have the following code inside the CS file of the page, i am trying to add an html button inside a div in the server side to close the alert modal dialog.
When I add the event to the button and try to fire it. The event doesn't fires.
So, where is the problem ?
public Alert(HtmlGenericControl alert ,string alertMessage)
{
vAlert = alert;
alert.Attributes.Add("class", "uk-modal");
alert.Attributes.Add("aria-hidden", "true");
alert.Attributes.Add("style", "display: none; overflow-y: scroll;");
HtmlGenericControl innerDiv = new HtmlGenericControl();
innerDiv.TagName = "div";
innerDiv.Attributes.Add("class", "uk-modal-dialog");
innerDiv.Attributes.Add("style", "top: 35.5px;text-align:center; padding:30px;");
HtmlInputButton btnclose = new HtmlInputButton();
btnclose.Attributes.Add("type", "button");
btnclose.Attributes.Add("id", "alert_close");
btnclose.Attributes.Add("runat", "server");
btnclose.Attributes.Add("class", "uk-modal-close uk-close");
btnclose.Attributes.Add("style", "padding:15px;");
btnclose.ServerClick += new EventHandler(btnclose_ServerClick);
innerDiv.Controls.Add(btnclose);
HtmlGenericControl p = new HtmlGenericControl();
p.TagName = "p";
p.InnerText = alertMessage;
innerDiv.Controls.Add(p);
alert.Controls.Add(innerDiv);
ShowAlert(alert);
}
private void btnclose_ServerClick(object sender, EventArgs e)
{
HideAlert(vAlert);
}
Can you help me ?

The button probably doesn't exist at the time when the server callback is executing.
You are using a dynamically created button. In order for it to be able to trigger a server side method, the button needs to be added and have it's event handler bound in an early stage of the page life cycle, such as On_Init.
We don't know when you call your "Alert" method, but it might very well too late. It also needs to be called on every postback - or the link between button and handler won't be there when the button causes a postback.

Why dynamically created Radmenu ItemClick event is not firing

I am dynamically creating a RadMenu. I want to use the menu click event of the RadMenu.
Actually I am using if(!Scriptmanager.IsInAsyncPostBack) condition.
Within the if condition I only write code to create the menu dynamically. I'll give the sample code for better understanding.
if (!src.IsInAsyncPostBack)
{
RadMenu menu = new RadMenu();
RadMenuItem item1 = new RadMenuItem();
item1.Text = "Home";
RadMenuItem item11 = new RadMenuItem();
item11.Text = "Home";
item1.Items.Add(item11);
RadMenuItem item2 = new RadMenuItem();
item2.Text = "About";
RadMenuItem item3 = new RadMenuItem();
item3.Text = "Contact";
menu.ItemClick += new RadMenuEventHandler(menu_ItemClick);
menu.Items.Add(item1);
menu.Items.Add(item2);
menu.Items.Add(item3);
Page.Controls.Add(menu);
}
void menu_ItemClick(object sender, RadMenuEventArgs e)
{
Response.Redirect("Home.aspx");
}
When page loading if(!IsInAsyncPostBack) condition true so the RadMenu is created dynamically and loaded in the page.
When I click the menu item, Postback becomes true, so the if condition fails and the menu
click event is not firing.
I wrote the menu click event outside of the if condition. In this case the menu click event is also not firing.
My exact requirement is that I want to use if(!IsInAsyncPostBack) postback condition as well as I need to use menu click event. Is it possible?

Add this in the Page_Init event and remove the if (!src.IsInAsyncPostBack) check. THis is the easiest way to create controls programmatically.
Probably your menu is ajax-enabled so a POST from it is partial, so your code does not recreate it, so it cannot raise its handler.

How to dynamically create EventHandlers for dynamically created buttons? C# VS2010

so, I have a form that is dynamically populated with textboxes and buttons.
How can I create EventHandlers for each of those buttons dynamically (ex: it generates 20 buttons, I need 20 eventhandlers). Each button will have the same function (to delete something from a database) but I need the program to know whenever any one of them is clicked to trigger that code.
// also, the button creation code is within a while() so I can't use it ouside that while (just pointing that out)
Code:
public void LoadElements()
{
//more code here
while(some condition)
{
// more code above
Button b = new Button();
b.Text = "Delete";
b.Name = "button" + j;
b.Location = new Point(240, Y);
Controls.Add(b);
// more code bellow
}
// more code here
}

Assign them like you would for any other event in your code. You can simply add an event handler doing something like:
b.Click += b_Click

Add in the loop:
b.Click+=New Eventhandler(b_Click);
(Just press TAB twice after typing b.Click+=).
Define the function b_Click outside of the loop. It will be invoked when anyone of those button is clicked.

How can i create dynamic buttons on button click event (C sharp ASP.NET)?

I want to create dynamic buttons on button click event(for example., btnCreateDynamic_Click).
I tried creating dynamic buttons on page_load event and Pre_int event.They are all working but i want to create them in button click event. How can i do this in c# asp.net?

Your button click event at the client will cause a page postback that will start the ASP.Net Page Life-cycle;
Your button click event on the server is a PostBackEvent and you should be able to use the same method call CreateMyButton() that you used in the Load or Init events.

An idea would be to create a list of buttons in which you'd store the buttons you created in btnCreateDynamic_click.
you could have a method like:
private Button CreateButton(string id, string name)
{
Button b = new Button();
b.Text = name;
b.ID = id;
b.Click += new EventHandler(Button_Click);
b.OnClientClick = "ButtonClick('" + b.ClientID + "')";
return b;
}
in btnCreateDynamic_click you could have something like:
Button b = CreateButton("dinamicBtn"+myDinamicButtonsList.Count.ToString(),"dinamicBtn"+myDinamicButtonsList.Count.ToString());
myDinamicButtonsList.add(b);
and in the pageLoad for example you could do something like
foreach(button btn in myDinamicButtonsList){
form1.Controls.Add(btn));
}
List<Button> myDinamicButtonsList = new List<Button>();
myDinamicButtonsList should be stored somewhere from where it could be retrieved after each request.
EDIT:
In page load you could have something like this:
if(Session["myDinamicButtons"] == null){
List<Button> myDinamicButtonsList = new List<Button>();
Session["myDinamicButtons"] = myDinamicButtonsList;
}
foreach(Button btn in Session["myDinamicButtons"] as List<Button>){
form1.Controls.Add(btn));
}
i didn't tested it but it should work.