CODEWITHSUNDEEP
c#wpfvisual-studioeventsevent-handling
Schrödinger's Box
Schrödinger's Box

Reputation: 3218

Unsubscribe / remove Event Handler with custom arguments

I subscribe / create a custom Event Handler with the following code:

myButton.Click += (sender, e) => MyButtonClick(sender, e, stuff1, stuff2);


I want to unsubscribe / remove and tried it like this:

myButton.Click += MyButtonClick;

But throws the following error:
No overload for 'MyButtonClick' matches delegate 'System.Windows.RoutedEventHandler'


And like this:

myButton.Click += MyButtonClick(sender, e, stuff1, stuff2);

But throws the following error:
Cannot implicitly convert type 'void' to 'System.Windows.RoutedEventHandler'


How do I unsubscribe / remove that same Event Handler?

Upvotes: 2

Views: 2988

Answers (3)

CarLoOSX
CarLoOSX

Reputation: 525

An example:

EventHandler myEvent = (sender, e) => MyMethod(myParameter);//my delegate

myButton.Click += myEvent;//suscribe
myButton.Click -= myEvent;//unsuscribe

private void MyMethod(MyParameterType myParameter)
{
 //Do something
}

Upvotes: 0

Coding Flow
Coding Flow

Reputation: 21881

It's because your method does not match the signature of your event handler. In your first example you are creating an anon method with the correct signature that calls your method and adding the anon method as the event handler.

If you no not like this approach then simple create a wrapper method that fulfills the signature and calls the other method, which is essentially what you are doing e.g.

public void MyButtonClickWrapper(object sender, EventArgs e)
{
    MyButtonClick(sender, e);
}

You can then wire this up in the normal way:

myButton.Click += MyButtonClickWrapper
myButton.Click -= MyButtonClickWrapper

Upvotes: 0

Sriram Sakthivel
Sriram Sakthivel

Reputation: 73482

When you use Lambda you need to keep a reference of it to unsubscribe.

Try this

RoutedEventHandler handler = (sender, e) => MyButtonClick(sender, e, stuff1, stuff2);
myButton.Click +=  handler;//Subscribe
//Some more code
myButton.Click -=  handler;//Unsubscribe

Upvotes: 5

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