Create event c# (not invoke or define)

[Fredrick Rivers]

Hi, I need to create a NEW event on c#: I need to execute a command when a local variable CHANGES, I know how to define, execute, etc events that are already stored in VS (buttonClicked,etc...) Is there a simple way to do this?
Many thanks for your time.

[Leito]

I don't know any mean to do that, but there should be a defined event (like buttonClicked...) that triggers the change of your local variable, isn't it ?

[Christian Binder]

You an't trigger an event when a local variable changes, but you can use a property instead of a local variable and there you can trigger the event.

//Define the event
event Action LocalVarChanged;
 
int _localVar = 0;
 
//Create a property for your local var
LocalVar {
  get { return _localVar; }
  set {
    _localVar = value;
    //Trigger the event
    if(event != null)
      event();
  }
}
 

[Curtis Rutland]

Christian's answer is exactly how to do this, if you want a specific event for a specific property.

If you want a single event for all your properties (with the EventArgs telling you which property changed), there's already an interface designed to do this for you: INotifyPropertyChanged.

Implementing that interface properly, and adding the invocation code to all your properties, will let you catch when any property changes, and react appropriately. This is useful for objects that will be used in ObservableCollections.