How to display tooltip when entering prohibited characters?

Question

.NET

private void emailBox_KeyPress(object sender, KeyPressEventArgs e)
    {


        if(!Char.IsLetter(e.KeyChar) && e.KeyChar != 8 && !Char.IsDigit(e.KeyChar) == true)
        {
            e.Handled = true;
            return;
        }
        else if (e.KeyChar < 33 &&  e.KeyChar > 47) // При вводе допустим этих символов tooltip не вылазит

        {
            toolTip1.IsBalloon = true;
            toolTip1.Show("Забыли ввести", this.emailBox, 1000);
        }
    }

It is necessary that the tooltip climbed out, just like when CapsLock was pressed

Answer 1

In WinForms, you can use the ErrorProvider for this.
Practical guide ErrorProvider.
By default, the error is shown as an icon next to the input field.