C#中简单验证输入的字符是否有效

private void IsNum(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == 8)
{
return;
}
else if (e.KeyChar > '9' || e.KeyChar < '0' )
{
e.Handled = true;
MessageBox.Show("无效字符");
}
}

　　　　//验证电话号码

private void txtPhone_KeyPress(object sender, KeyPressEventArgs e)
{
IsNum(sender, e);

}

　　//验证flost工资或价格

private void txtBasePay_KeyPress(object sender, KeyPressEventArgs e)
{
if(e.KeyChar!='.')
IsNum(sender, e);
}

　　//验证身份证号

private void txtIDCard_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar != 13)
{
IsNum(sender, e);
}
else
{
SendKeys.Send("{Tab}");
}
}