How to remove all event handlers from an event

Question

To create a new event handler on a control you can do this

c.Click += new EventHandler(mainFormButton_Click); 

or this

c.Click += mainFormButton_Click; 

and to remove an event handler you can do this

c.Click -= mainFormButton_Click; 

But how do you remove all event handlers from an event?

Answer 1

I found a solution on the MSDN forums. The sample code below will remove all Click events from button1.

public partial class Form1 : Form {     public Form1()     {         InitializeComponent();          button1.Click += button1_Click;         button1.Click += button1_Click2;         button2.Click += button2_Click;     }      private void button1_Click(object sender, EventArgs e)  => MessageBox.Show("Hello");     private void button1_Click2(object sender, EventArgs e) => MessageBox.Show("World");     private void button2_Click(object sender, EventArgs e)  => RemoveClickEvent(button1);      private void RemoveClickEvent(Button b)     {         FieldInfo f1 = typeof(Control).GetField("EventClick",              BindingFlags.Static | BindingFlags.NonPublic);          object obj = f1.GetValue(b);         PropertyInfo pi = b.GetType().GetProperty("Events",               BindingFlags.NonPublic | BindingFlags.Instance);          EventHandlerList list = (EventHandlerList)pi.GetValue(b, null);         list.RemoveHandler(obj, list[obj]);     } } 

Answer 2

You guys are making this WAY too hard on yourselves. It's this easy:

void OnFormClosing(object sender, FormClosingEventArgs e) {     foreach(Delegate d in FindClicked.GetInvocationList())     {         FindClicked -= (FindClickedHandler)d;     } }