TextBox KeyPress decimal number input validation.

gistfile1.cs

      private void ValidateKeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
      {
         if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar) && e.KeyChar != '.')
         {
            e.Handled = true;
         }

         // Only allow one decimal point
         if (e.KeyChar == '.' && (sender as StxTextBox).Text.IndexOf('.') > -1)
         {
            e.Handled = true;
         }
      }