C#CS结构，控制输入数字的方法

只允许输入正数
        private void txtWeight_KeyPress(object sender, KeyPressEventArgs e)
        {
            if ((e.KeyChar < 48 || e.KeyChar > 57) && (e.KeyChar != 8) && e.KeyChar != '.')
            {
                e.Handled = true;
            }
           
        }