How to validate text box with C# in windows application ?

private void TextBox1_KeyPress(object sender, KeyPressEventArgs e)
{
   if ((e.KeyChar >= 47 && e.KeyChar <= 58) || (e.KeyChar == 46) || (e.KeyChar == 8))
 {
   e.Handled = false;
 }
else
 {
   e.Handled = true;
   MessageBox.Show("Please enter only number");
 }
}