Question

以下是使用以下代码解决问题的简单步骤...

运行项目
创建新邮件
添加attacment
关闭邮件 - 我第一次要求保存更改 - 我选择否
关闭Outlook应用程序 - 我被问过两次保存更改...为什么？

这是我的示例代码......

Imports System.Runtime.InteropServices

Public Class ThisAddIn

    Private Shared _currentMailItem As Outlook.MailItem


    Private Sub ThisAddIn_Startup() Handles Me.Startup
        AddHandler Me.Application.ItemLoad, AddressOf LoadMail
    End Sub


    Private Sub ThisAddIn_Shutdown() Handles Me.Shutdown
    End Sub


    Private Shared Sub LoadMail(Item As Object)
        If TypeOf Item Is Outlook.MailItem Then
            _currentMailItem = TryCast(Item, Outlook.MailItem)
            AddHandler _currentMailItem.Open, AddressOf OpenMail
        End If
    End Sub


    Private Shared Sub OpenMail(ByRef Cancel As Boolean)
        If String.IsNullOrEmpty(_currentMailItem.EntryID) Then
            AddHandler _currentMailItem.AttachmentAdd, AddressOf MailItem_AttachementAdded
            AddHandler _currentMailItem.Close, AddressOf MailItem_Close
        End If
    End Sub


    Private Shared Sub MailItem_AttachementAdded(e As Outlook.Attachment)
        For Each a As Outlook.Attachment In _currentMailItem.Attachments
        Next
    End Sub


    Private Shared Sub MailItem_Close(ByRef cancel As Boolean)
        If String.IsNullOrEmpty(_currentMailItem.EntryID) Then
            RemoveHandler _currentMailItem.AttachmentAdd, AddressOf MailItem_AttachementAdded
            RemoveHandler _currentMailItem.Close, AddressOf MailItem_Close
        End If
    End Sub

End Class

在关闭应用程序以保存更改时，你能看出为什么它会问我两次吗？

此外，我不确定何时使用Marshal.ReleaseComObject（） - 就像在我的For Each a As Outlook.Attachment In _currentMailItem.Attachments中一样......在循环中我是Marshal.ReleaseComObject（a）吗？

由于

... UPDATE

尽管我试图释放对象，但是这段代码仍然失败......

Imports System.Runtime.InteropServices

Public Class ThisAddIn

    Private _currentMailItem As Outlook.MailItem


    Private Sub ThisAddIn_Startup() Handles Me.Startup
        AddHandler Me.Application.ItemLoad, AddressOf LoadMail
    End Sub


    Private Sub ThisAddIn_Shutdown() Handles Me.Shutdown
    End Sub


    Private Sub LoadMail(Item As Object)
        If TypeOf Item Is Outlook.MailItem Then
            _currentMailItem = TryCast(Item, Outlook.MailItem)
            AddHandler _currentMailItem.Open, AddressOf OpenMail
        End If
    End Sub


    Private Sub OpenMail(ByRef Cancel As Boolean)
        If String.IsNullOrEmpty(_currentMailItem.EntryID) Then
            AddHandler _currentMailItem.AttachmentAdd, AddressOf MailItem_AttachementAdded
            AddHandler _currentMailItem.Close, AddressOf MailItem_Close
        End If
    End Sub


    Private Sub MailItem_AttachementAdded(e As Outlook.Attachment)
        For i As Integer = 0 To _currentMailItem.Attachments.Count - 1
            Dim a As Outlook.Attachment = _currentMailItem.Attachments(i + 1)
            Marshal.ReleaseComObject(a)
            a = Nothing
        Next
    End Sub


    Private Sub MailItem_Close(ByRef cancel As Boolean)
        If String.IsNullOrEmpty(_currentMailItem.EntryID) Then
            RemoveHandler _currentMailItem.AttachmentAdd, AddressOf MailItem_AttachementAdded
            RemoveHandler _currentMailItem.Close, AddressOf MailItem_Close
        End If
        Marshal.ReleaseComObject(_currentMailItem)
        _currentMailItem = Nothing
    End Sub

End Class

Answer 1

看起来您不会立即在代码中释放基础COM对象。保持对用户关闭的对象的引用会导致这样的对话。

完成使用后，使用System.Runtime.InteropServices.Marshal.ReleaseComObject释放Outlook对象。然后在Visual Basic中将变量设置为Nothing（C＃中为null）以释放对该对象的引用。请在Systematically Releasing Objects文章中详细了解相关内容。

使用For循环代替ForEach循环。后者不允许立即释放所有底层COM对象。您可能会发现When to release COM objects in Office add-ins developed in .NET页面很有用。

VSTO：Outlook要求“保存更改？”3次......为什么？

1 个答案: