VB.Net Abstrct的实例

乐博网lob.cn提示：调试环境为 vs2005 +  windows2003 / windows2008 / xp / vista
Public Class AbstrctForm
    Dim aa As InheritsClass = New InheritsClass
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim str As String = textbox1.text
        Dim a As String = aa.ToUpper(str)
        MessageBox.Show(a)
        aa.ReturnLength(str)
    End Sub
End Class
Class InheritsClass
    Inherits AbstractClass  '更多.net源码和实例，来自乐博网 www.lob.cn
    Overrides Function ToUpper(ByVal str As String) As String
        Return "大写" & str.ToUpper
    End Function
End Class
Public MustInherit Class AbstractClass
    Overridable Function ToUpper(ByVal str As String) As String
        Return str.ToUpper
    End Function
    Sub ReturnLength(ByVal str As String)
        MessageBox.Show("字符串长度为：" & str.Length)
    End Sub
End Class