private void txtPrinterNumber_KeyPress(object sender, 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 TextBox).Text.IndexOf('.') > -1))
    {
        e.Handled = true;
    }
}

它可以完成 - 它并不复杂，只是烦人，因为你必须处理它防止粘贴添加alpha的地方。



更好的解决方案是使用NumericUpDown控件，它可以为你完成所有。



如果您打算手动执行此操作，请考虑查看TextChanged事件并使用Regex.Replace而不是IsMatch - 但不要忘记光标位置可能需要更正。

It can be done - it's not complex, it's just annoying, because you have to handle it in a number of places to prevent paste adding alpha as well.

The better solution is to use a NumericUpDown control, which does it all for you.

If you are going to do it manually, consider looking at the TextChanged event and using Regex.Replace instead of IsMatch - but don't forget the cursor position may need correcting.