stack issue

Dave Kreskowiak

I ignored your last code post because it's not the same as your original post.

if (true)
    ...

if (true)
    ...

is NOT the same as:

if (something)
    ...

if (something**\_else**)
    ...

Your last code post is identical in output to:

string text;

if (true)
{
text = "closed";
FormClosed += delegate( object sender, FormClosedEventArgs e )
{ MessageBox.Show( text ); };

text = "closing";
FormClosing += delegate( object sender, FormClosingEventArgs e )
    { MessageBox.Show( text ); };

}

The problem was never in the compiler, but in your logic.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
2006, 2007

Goncalo Oliveira

You don't even need to put the if there... Now... all this not to answer my question?? Come one... you can do better than that, can't you? If I said that it wasn't relevant, it's because it wasn't... Now... you can remove the if... are you gonna answer my question or are you just gonna pretend you're so very awesome? Cheers

Gonçalo A.

Dave Kreskowiak

Kensho wrote:

Come one... you can do better than that, can't you? If I said that it wasn't relevant, it's because it wasn't

That's what YOU think. It WAS relevant. The key piece of information was, and still is, missing. I already explained to why that's the case, but you keep insisting that it's not. It's not me that has the problem, it's you. The first rule of asking a question is to listen.

Kensho wrote:

Now... you can remove the if... are you gonna answer my question or are you just gonna pretend you're so very awesome?

I already answered this in my previous post. Sure, you can remove the if. Your code would still be this:

string text;
text = "closed";
FormClosed += delegate( object sender, FormClosedEventArgs e )
{ MessageBox.Show( text ); };

text = "closing";
FormClosing += delegate( object sender, FormClosingEventArgs e )
{ MessageBox.Show( text ); };

Perhaps you're misunderstanding what the two delegate statements are doing??

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
2006, 2007

Dave Kreskowiak

Kensho wrote:

Come one... you can do better than that, can't you? If I said that it wasn't relevant, it's because it wasn't

That's what YOU think. It WAS relevant. The key piece of information was, and still is, missing. I already explained to why that's the case, but you keep insisting that it's not. It's not me that has the problem, it's you. The first rule of asking a question is to listen.

Kensho wrote:

Now... you can remove the if... are you gonna answer my question or are you just gonna pretend you're so very awesome?

I already answered this in my previous post. Sure, you can remove the if. Your code would still be this:

string text;
text = "closed";
FormClosed += delegate( object sender, FormClosedEventArgs e )
{ MessageBox.Show( text ); };

text = "closing";
FormClosing += delegate( object sender, FormClosingEventArgs e )
{ MessageBox.Show( text ); };

Perhaps you're misunderstanding what the two delegate statements are doing??

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
2006, 2007

Goncalo Oliveira

If the code does the same, it WAS IRRELEVANT; if it was relevant, the code would do something different. I'll just state the output of that code... When you close the form, two message boxes will appear... One will say "closing", and the other one will say "closing". I said this right from the start.

Gonçalo A.

S Senthil Kumar

One word : closures. A closure captures the value of a variable in its lexical scope. Your event handlers are anonymous functions which capture the local variable text. Behind the scenes, the compiler generates a new class with the captured variable as a member and rewires the event handler so that it calls a method on the generated class. That class then uses the member variable's value to fill in for the captured variable. The compiler updates the generated class instances with the value of captured variables as long as the captured variables are in scope. In your case, text was declared outside the scope of both if blocks, so the compiler dutifully updated the value of the variable when you changed it inside the second if block. Just to make things clear, this is not done only for reference types (like string).

   delegate void Func();

    static void Main()
    {
        Func\[\] f = new Func\[10\];
        for (int i = 0; i < 10; ++i)
        {
            f\[i\] = delegate { Console.WriteLine(i); };
        }

        foreach (Func func in f)
        {
            func();
        }
    }

This will print 10 all ten times.

Regards Senthil [MVP - Visual C#] _____________________________ My Blog | My Articles | My Flickr | WinMacro

Goncalo Oliveira

Exactly! Now that's an answer. Thank you. Cheers

Gonçalo A.

Dave Kreskowiak

if (true){
text = "closed";
FormClosed += delegate( object sender, FormClosedEventArgs e )
{ MessageBox.Show( text ); };
text = "closing";
FormClosing += delegate( object sender, FormClosingEventArgs e )
{ MessageBox.Show( text ); };
}

So you mean to tell me that you thought text in each delegate would get a copy of the current contents of the text variable when the delegates were created?? You'll have to excuse me as I (wrongly) assumed you knew how variables worked. This was such a basic concept you were missing that I didn't even consider it a possibility that that's where you were misunderstanding the code. To me, it was obvious this would be the behavior. I originally thought that you were wondering why both sections of code were being run because both if statements were being evaluated to true.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
2006, 2007

Goncalo Oliveira

bwahahahahaha I really had to laugh on this one... And you're a Microsoft MVP??? Well... you're from VB, so... I guess I have to understand. First... it's not a variable matter. It's a closures matter. And I said from the start what would happen; you were the one saying otherwise... so... don't try to cover up your stupidity now... And... weren't you supposed to be here to help? Get over your frustration, it's unhealthy for this forum users. Cheers

Gonçalo A.

Dave Kreskowiak

One word: Blacklisted.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
2006, 2007

Goncalo Oliveira

In lack of a wiser answer... I don't mind... Cheers

Gonçalo A.