private void UserAmountTextBox_KeyPress(object sender, KeyPressEventArgs e)
{
// allow backspace
if (e.KeyChar == (char)Keys.Back)
{
return;
}
if (!Char.IsDigit(e.KeyChar) && e.KeyChar != '.') // not a digit and not decimal
{
// don't write - exit
e.Handled = true;
return;
}
else if (e.KeyChar == '.' && UserAmountTextBox.Text.Contains(".")) // decimal but contains decimal already
{
// don't write - don't clear on next digit - exit
e.Handled = true;
clearUserAmountTextBoxNextDigit = false;
return;
}
else if (e.KeyChar == '.') // decimal
{
// allow - don't clear on next digit - exit
clearUserAmountTextBoxNextDigit = false;
return;
}
var enter = (char)Keys.Enter;
var userKey = e.KeyChar;
if (clearUserAmountTextBoxNextDigit && (userKey != enter) && (userKey != '+') && (userKey != '-'))
{
clearUserAmountTextBoxNextDigit = false;
UserAmountTextBox.Clear();
}
}
private void ClearCalcButton_Click(object sender, EventArgs e)
{
UserAmountTextBox.Clear();
}