Removing all buttons from form

Hello all,

Why did one method work but the other did not and produce weird results?

I was trying to remove all controls of type button from a form. I tried two methods:

This worked:

public void ClearButtons()

{

for (int i = 0; i < this.Controls.Count; i++)

{

if (Controls[i] is Button)

{

Controls.RemoveAt(i);

i--;

}

Didn't work (I got weird results, some buttons would stay on the form):

foreach(Control control in Controls)

{

if (control is Button)

Controls.Remove(control);

}