如何从文本框继承并覆盖键和键事件？

Question

I want to create a new class inherits from System.Windows.Forms.TextBox and assign keypress and keyup events to my control.

Something like this :

    class CurrencyTextbox : TextBox
    {
        private void CurrencyTextbox_KeyPress(object sender, KeyPressEventArgs e)
        {
            char ch = e.KeyChar;

            if (!Char.IsDigit(ch) && ch != 8 && ch != 13)
            {
                e.Handled = true;
            }
        }

        private void CurrencyTextbox_KeyUp(object sender, KeyEventArgs e)
        {
            if (!string.IsNullOrEmpty(CurrencyTextbox.Text))
            {
                System.Globalization.CultureInfo culture = new System.Globalization.CultureInfo("en-US");
                Int64 valueBefore = Int64.Parse(CurrencyTextbox.Text, System.Globalization.NumberStyles.AllowThousands);
                CurrencyTextbox.Text = String.Format(culture, "{0:N0}", valueBefore);
                CurrencyTextbox.Select(CurrencyTextbox.Text.Length, 0);
            }
        }
    }

Answer 1

You should override the protected virtual void OnKeyUp(KeyEventArgs e) .
Make sure to call base.OnKeyUp(e) , or the event will not be raised.

You can also add a regular event handler by writing KeyUp += CurrencyTextbox_KeyUp