明天再学。。。

  有一点点资料：http://bbs.aspx.cn/dotnetbbs/Showtopic.aspx?Forum_ID=5&Id=36871

 If TextBox1.Text = "" Then
            MessageBox.Show("You must enter a name.", "Name Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        Else
            ' Code to act on the data entered would go here.
        End If