C# Outlook 2007 COM 互操作应用程序不退出！

知道为什么以下代码不退出通过 COM 互操作创建的 Outlook 2007 进程吗？

Microsoft.Office.Interop.Outlook.Application app = new Microsoft.Office.Interop.Outlook.Application();

var item = app.Session.OpenSharedItem("C:\\test.msg") as Microsoft.Office.Interop.Outlook.MailItem;
string body = item.HTMLBody;
int att = item.Attachments.Count;

(item as Microsoft.Office.Interop.Outlook._MailItem).Close(Microsoft.Office.Interop.Outlook.OlInspectorClose.olDiscard);
System.Runtime.InteropServices.Marshal.ReleaseComObject(item);

(app as Microsoft.Office.Interop.Outlook._Application).Quit();
System.Runtime.InteropServices.Marshal.ReleaseComObject(app);
System.Diagnostics.Debugger.Break();

使用 Word 可以得到几乎相同的片段，所以我想知道我是否忘记清理一些东西......

您的代码中引用了第三个 COM 对象：app.Session。这也必须正确释放。试试这个代码：

Microsoft.Office.Interop.Outlook.Application app = null;
Microsoft.Office.Interop.Outlook.NameSpace session = null;
Microsoft.Office.Interop.Outlook.MailItem item = null;

try {
    app = new Microsoft.Office.Interop.Outlook.Application();
    session = app.Session;
    item = session.OpenSharedItem("C:\\test.msg") as Microsoft.Office.Interop.Outlook.MailItem;

    string body = item.HTMLBody;
    int att = item.Attachments.Count;

    (item as Microsoft.Office.Interop.Outlook._MailItem).Close(Microsoft.Office.Interop.Outlook.OlInspectorClose.olDiscard);

    (app as Microsoft.Office.Interop.Outlook._Application).Quit();
} finally {
    if(item != null) {
        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(item);
    }
    if(session != null) {
        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(session);
    }
    if(app != null) {
        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(app);
    }
}