Question

I´m trying to remove textbox controls from a panel in a event Button click:

private void button2_Click(object sender, EventArgs e)
{
   panel1.Controls.OfType<TextBox>().ToList().Clear();
}

but it doesn´t work

Answer 1

The reason why your approach is not working, is that you are creating a new List, not connected to the panel (your ToList call), then clearing that list, effectively doing nothing.

You need to remove each item on the Controls collection directly:

 var textBoxes = panel1.Controls.OfType<TextBox>().ToList();
 foreach(var box in textBoxes)
     panel1.Controls.Remove(box);