C# / WPF create new button array with multiple function

Question

I have wrote a code with this description: First button calls FuncPopup(); function, after that every popup dialog creates new button. New button Create FuncPopup();. Old buttons should have various behavior.

        private void FuncPopup()
    {
        FuncMenu popup = new FuncMenu();
        popup.ShowDialog();
        if (popup.DialogResult.HasValue && popup.DialogResult.Value)
        {
            i++;
            newBtn[i] = new Button();
            FuncGird.Children.Add(newBtn[i]);
            Grid.SetColumn(newBtn[i], i);
            Grid.SetRow(newBtn[i], j);
            newBtn[i].Click += (sender, e) => clicked(i);
        }
    }
    void clicked(int g) {
        if (g >= i) 
        {
            FuncPopup(); 
        }
        else (g < i){
            OtherFunction();
        }
    }

i is a global variable. I expect Old buttons run OtherFunction(); but they always run FuncPopup();.

Evk · Accepted Answer · 2017-03-30 19:53:54Z

1

That's because as you said i is global variable, and you attach the following handler:

 newBtn[i].Click += (sender, e) => clicked(i);

And you increment i all the time. You might think that value of i is fixed at the moment you attach this handler but it's not so. i in clicked(i) is the same global variable, which increments with every call. So g always equals i in that handler, and so for all buttons FuncPopup is called.

Instead save i to local variable and use that:

int tmp = i;
newBtn[i].Click += (sender, e) => clicked(tmp);

answered Mar 30, 2017 at 19:53

Evk

102k8 gold badges156 silver badges204 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Mohammad Farahi Over a year ago

Great job, I have defined tmp variable locally, the result became what I expected.

Collectives™ on Stack Overflow

C# / WPF create new button array with multiple function

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related