using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace UpperText { public class UpperText : TextBox { protected override void OnTextChanged(System.EventArgs e) { // Changing text entered by the user to upper case int sel = SelectionStart; Text = Text.ToUpper(); SelectionStart = sel; base.OnTextChanged(e); } } }