How to make c# action happen when changing the value of a variable?

Question

C++ / C#

I have a variable and I need to track the change, and if it has changed, then erase its value

Answer 1

You make a property instead of a "variable" and inside the setter you call some method that will notify interested parties about the change.
For example like this:

public class Test {
  private int _someValue;
  public int SomeValue
  {
    get => _someValue;
    set {
      if(value != _someValue) {
        _someValue = value;
        NotifyAboutChange(); // То самое "действие"
      }
    }
  }
}

You can read about events here:
https://docs.microsoft.com/ru-ru/dotnet/csharp/lan...

Answer 2

To do this, an event is created: it is called by the method where the variable is used. Event subscribers receive information about the current value of the variable and execute their code.

Answer 3

Or use some reactive framework
https://www.nuget.org/packages/ReactiveProperty/