How to bind a function to Click event of each control in an array of controls in C#

Question

When you create an array of controls in C#, how can you bind a function that receives the index of the clicked button to their click event?

Here's some code solely for better understanding. Somewhere on top of the code you define the buttons:

Button [] buttons = new Button[100];

The standard Click event of them looks like this:

private void myClick(object sender, EventArgs e)
{

}

And normally you bind it this way:

for (int i = 0; i < 100; i++)
    buttons[i].Click += myClick;

But I want the event handler to be in this form:

private void myClick(int Index)
{

}

How should I bind click events to the above function with / without interim functions?

I thought about using delegates, Func<T, TResult> notation, or somehow pass a custom EventArgs which contains the Index of the clicked button; but I wasn't successful due to lack of enough C# knowledge.

If any of you are going to suggest saving the index of each control in its Tag: Yes it was possible but I don't wanna use it for some reason, since if you have a class which throws some events but doesn't have a Tag property or something, this way is useless.

Bas · Accepted Answer · 2011-06-22 12:27:36Z

6

int index = i;    
buttons[index].Click += (sender, e) => myClick(index);

As posted in the comment below, using 'i' will use the same variable for all controls due to it's scope. It's therefore necessary to create a new variable in the same scope as the lambda expression.

edited Jun 22, 2011 at 12:27

answered Jun 22, 2011 at 11:16

Bas

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1 Comment

Hossein Over a year ago

In a for loop, i had to write var index=i; buttons[i].Click += (sender, e) => myClick(index); See stackoverflow.com/q/6439477

DanielB · Accepted Answer · 2011-06-22 11:16:36Z

2

private void myClick(object sender, EventArgs e)
{
    int index = buttons.IndexOf(sender as Button);
}

answered Jun 22, 2011 at 11:16

DanielB

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2 Comments

Bas Over a year ago

This requires buttons to be a field, and linear search in the buttons array

DanielB Over a year ago

I'am aware of that, and I voted up your answer, because I like them. But at all, I would not miss the EventArgs in a handler. May be on further development, its required to interact with them.

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