主题：大家帮我看一下这个退出系统的按钮有什么问题啊！！！

代码

For Each dt As DataTable In DataTables
    If dt.HasChanges Then
        Dim result As Object = MessageBox.Show("数据已修改,是否保存?","提示",MessageBoxButtons.YesNoCancel,MessageBoxIcon.Information)
        If result = DialogResult.Yes Then
            DataTables.Save
        Else If result = DialogResult.No Then
            DataTables.RejectChanges
        Else If result = DialogResult.Cancel Then
            Syscmd.Edit.Undo()
        End If
        Exit For
    End If
Next

If MessageBox.Show("确认退出吗?","请确认!",MessageBoxButtons.OKCancel,MessageBoxIcon.Question) = DialogResult.OK Then
    Syscmd.Project.Exit()
Else
    Syscmd.Edit.Undo()
End If