My dynamically created link buttons event won't fire.

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I am dynamically creating link buttons based on how many files that were created earlier on in the application. The links are being created successfully, however, when I try to click them, it just does a postback and nothing else happens.

Can someone point me in the right direction with my code? Thank you!

C#

LinkButton btnFile = new LinkButton();
           for (int i = 0; i < convertedFiles.Count; i++)
           {
               foreach (var filess in convertedFiles)
               {
                   btnFile.Text = "Download file for agency " + Agencynumber + "<br>";
                   btnFile.ID = filess;
                   btnFile.Visible = true;
                   btnFile.Click += new System.EventHandler(this.button_Click);
                   Form1.Controls.Add(btnFile);
               }

           }
protected void button_Click(object sender, EventArgs e)
     {
       //some code here
     }

Posted 29-Jun-12 11:05am

Richard C Bishop

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Zoltán Zörgő 29-Jun-12 17:17pm

//some code here should happen, if this is really empty, what you expect?

Sergey Alexandrovich Kryukov 29-Jun-12 23:15pm

That's one of my points. It could be even non-empty, still doing nothing observable -- please see my answer.
--SA

Richard C Bishop 29-Jun-12 17:18pm

It is not empty, I only posted relevent code.

Sergey Alexandrovich Kryukov 29-Jun-12 23:16pm

You are right, but if you see something which looks like a miracle, you can check up more possibilities for a problem.
--SA

Jackie00100 29-Jun-12 17:18pm

Dosen't event normally suppose to be public?

lewax00 29-Jun-12 17:26pm

Shouldn't make a difference as long as the signature is correct (return value and argument types), it only needs to be seen internally. You can even use lambdas for event handlers.

Jackie00100 29-Jun-12 17:40pm

internal will do yea, but my thinking is that the form/designer/Class etc. is in a single class and there by it should be internal or public and not protected as in the code? unless the above is inherit from somewhere of cause

Sergey Alexandrovich Kryukov 29-Jun-12 23:17pm

If is not shown. A even should be non-private, that's all. Could be internal, public, protected, internal protected...
--SA

[no name] 29-Jun-12 17:41pm

Your code works for me... as long as you realize that your code, as presented, is creating one single button...

Sergey Alexandrovich Kryukov 29-Jun-12 23:14pm

Agree. Still I have two assumption of possible problems, please see my answer.
--SA

Richard C Bishop 2-Jul-12 9:52am

Dang, I am trying to create a button for each file and then have code run that prompts the user to save the files.

Zoltán Zörgő 30-Jun-12 7:58am

Have you checked with some sniffer what exactly is sent back?

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Sergey Alexandrovich Kryukov · Accepted Answer · 2012-06-29T17:14:00

As soon as you can see the button created by this code, the event should fire. I would rather assume that you fail to observe it. I can suggest to check up two things:

First, sometimes you create two buttons looking nearly the same way. One button could hide another one or something like that. You might click a wrong button. I remember such cases in real life.

Second, you might click a right button, and the event fires, but the code of even handler does no help you to see it, as it does not do anything you could observe, by some mistake. To make sure, run it under debugger, set a breakpoint at the very beginning of the handler method, at first.

[EDIT]

Wait a minute! There is a problem. I just noticed that you create a button outside the loops. Let's say, the inner loop is repeated N times. It means that you create an instance of the same very button N times into the same parent control (which is your form Form1). Moreover, you add the same very event handler to the invocation list of the same very button instance, and you do it N times!

It cannot make any reasonable sense. (Sigh…)

—SA

Wes Aday · Accepted Answer · 2012-07-02T10:39:00

I am going to take this a step further. I think that your problem is much worse than what Sergey indicates. Let's break down what it is that you are doing:

C#

LinkButton btnFile = new LinkButton();
           for (int i = 0; i < convertedFiles.Count; i++)
           {
               foreach (var filess in convertedFiles)
               {
                   //removed extraneous
                   Form1.Controls.Add(btnFile);
               }

           }
protected void button_Click(object sender, EventArgs e)
     {
       //some code here
     }

Now you are creating a button dynamically but you are adding the same button over and over. But it's worse than that. Take a look at your loops. You have what appears to be a list of strings(maybe) that you are iterating over. Then we get to the foreach where we iterate over the same collection again! Do you really want that? If your convertedFiles collection contained, say, 10 strings, your for loop runs 10 times and then your foreach adds 10 buttons on each iteration! That's a lot of buttons.

I think that your entire routine could be boiled down to the following and I believe that this is what you intended to do:

C#

foreach (var filess in convertedFiles)
               {
                   LinkButton btnFile = new LinkButton();
                   btnFile.Text = "Download file for agency " + Agencynumber + "<br>";
                   btnFile.ID = filess;
                   btnFile.Visible = true;
                   btnFile.Click += new System.EventHandler(button_Click);
                   Form1.Controls.Add(btnFile);
               }
protected void button_Click(object sender, EventArgs e)
     {
       //some code here
     }

Move the button creation to the foreach loop and get rid of the for loop altogether.

My dynamically created link buttons event won't fire.

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