Make all Controls on a Form read-only at once

Question

Does anyone have a piece of code to make all Controls (or even all TextBoxes) in a Form which is read-only at once without having to set every Control to read-only individua

Answer 1

I haven't tested this, but it should work:

foreach (var textBox in this.Controls.OfType())
    textBox.ReadOnly = true;

Edit: This is not such a good solution it seems: see Timwi's comment.