Checking if a method is attached to an event - wpf

Question

Is there a way in WPF to check if an event has a method attached to it?
I'd like to be able to do something like
if (MyEvent != Null)
{
...
}

Answer 1

Since you are creating your own event, it is possible to check if a method is attached to it or not.
Below I have defined a method IsMethodAttachedToMyEvent which will check if the given Action is attached to MyEvent or not. I have used the GetInvocationList() method of MyEvent to loop through the attached methods.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.ComponentModel;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public event Action MyEvent;
public MainWindow()
{
InitializeComponent();
MyEvent += new Action(MainWindow_MyEvent);
MessageBox.Show("Is MainWindow_MyEvent attached\n\n" + IsMethodAttachedToMyEvent(new Action(MainWindow_MyEvent) ));
MessageBox.Show("Is MainWindow_MyEvent_1 attached\n\n" + IsMethodAttachedToMyEvent(new Action(MainWindow_MyEvent_1)));
}
public bool IsMethodAttachedToMyEvent(Action methodToCheck)
{
if (MyEvent != null)
{
foreach (Action act in MyEvent.GetInvocationList())
{
if (act.Method == methodToCheck.Method)
{
return true;
}
}
}
return false;
}
void MainWindow_MyEvent()
{
throw new NotImplementedException();
}
void MainWindow_MyEvent_1()
{
throw new NotImplementedException();
}
}
}