Question

I am creating a custom control and i want to add some properties in it.
On few of the properties i want to create some events.
Say
if i have a property

public int Date {get; set;}

now if its value is changing i want to trigger a change event. SO how can i add event on this

Answer 1

Use a “normal” property rather than an automatic property, and raise the change event in the setter:

private int _date;

public int Date
{
  get { return _date; }
  set
  {
    if (value != _date)
    {
      _date = value;
      // raise change event here
    }
  }
}

To raise the change event, if this is a standard INotifyPropertyChanged.PropertyChanged event:

PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
  handler(this, new PropertyChangedEventArgs("Date");
}

It’s recommended practice to isolate this into an OnPropertyChanged method.

If you’re raising a custom DateChanged event, the logic will be similar but with different names and event args.