防止在Outlook收件箱的一个特定子文件夹中删除电子邮件

我正试图找出如何限制Outlook 2010中的一个文件夹，使其邮件项被删除。我有下面的代码示例，工作得很好，但只适用于收件箱文件夹(OlDefaultFolders.olFolderInbox)。我想弄清楚如何限制一个文件夹和一个文件夹仅低于收件箱。例如Inbox'ReadMail，我想阻止用户只从ReadMail中删除。事先感谢您的帮助。

 public partial class ThisAddIn
{
    Microsoft.Office.Interop.Outlook.MailItem mail = null;
    Outlook.Inspectors inspectors = null;
    Outlook.Folder fldr = null;
    private void ThisAddIn_Startup(object sender, System.EventArgs e)
    {
        inspectors = this.Application.Inspectors;
        // Is there a way to edit the folloing line to point to a certain sub folder of the inbox folder?
        inspectors.NewInspector += new Microsoft.Office.Interop.Outlook.InspectorsEvents_NewInspectorEventHandler (Inspectors_NewInspector);
        fldr = (Outlook.Folder)this.Application.Session.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderInbox);
        fldr.BeforeItemMove += new Microsoft.Office.Interop.Outlook.MAPIFolderEvents_12_BeforeItemMoveEventHandler(fldr_BeforeItemMove);
    }
    void fldr_BeforeItemMove(object Item, Microsoft.Office.Interop.Outlook.MAPIFolder MoveTo, ref bool Cancel)
    {
        MessageBox.Show("You are not permitted to delete emails from this folder");
        Cancel = true;
    }

fldr = (Outlook.Folder)this.Application.Session.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderInbox);

fldr = (Outlook.Folder)this.Application.Session.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderInbox).Folders["ReadMail"];