using System.Windows.Forms; namespace BizHawk { public class HexTextBox : TextBox { public HexTextBox() { CharacterCasing = CharacterCasing.Upper; } protected override void OnKeyPress(KeyPressEventArgs e) { if (e.KeyChar == '\b' || e.KeyChar == 22 || e.KeyChar == 1 || e.KeyChar == 3) { return; } else if (!InputValidate.IsValidHexNumber(e.KeyChar)) { e.Handled = true; } } } }