如何通过c＃在所有Outlook共享邮箱文件夹中一次“搜索所有邮箱”？

Question

I want to mimic the latest version of Outlook's search functionality via c# and a windows form. Specifically, I want to "Search All Mailboxes" for a given string. There are over 50 folders and 90,000 emails.

Currently, I am able to search any one folder using LINQ and get results. I wrote some code to iterate through all the folders and create one massive IEnumberable that I can query.

public IEnumerable<MailItem> SharedInbox
    {

        get
        {
            outlook.ActiveExplorer().Session.GetDefaultFolder(OlDefaultFolders.olFolderInbox);
            Outlook.Recipient recip = Outlook.Application.Session.CreateRecipient("TOCCard@Capitalone.Com");
            Microsoft.Office.Interop.Outlook.MAPIFolder folder =
                    outlook.GetNamespace("MAPI").GetSharedDefaultFolder(recip, OlDefaultFolders.olFolderInbox);
            Folders subFolders = folder.Folders;
            IEnumerable<MailItem> mItems  = folder.Folders[1].Items.OfType<MailItem>();

            if (recip.Resolve())
            {
                System.Diagnostics.Debug.WriteLine("Email Address Resolve Successful.\r\n");
                try
                {
                    foreach (MAPIFolder fold in subFolders)
                    {
                        System.Diagnostics.Debug.WriteLine("Try Folder: " + fold.Name + " \r\n");
                        try
                        {
                           mItems = mItems.Concat(fold.Items.OfType<MailItem>());
                        }
                        catch
                        { System.Diagnostics.Debug.WriteLine("No items found:\r\n"); }
                    }


                    return mItems;
                }
                catch
                {
                    return null;
                }

            }
            else
            {
                System.Diagnostics.Debug.WriteLine("ELSE");
                return null;

            }

        }

This eventually works, but you can probably imagine that this excruciatingly slow and as such is useless. I am new to LINQ and I feel like there must be a faster way. Can this code be adjusted? I am not an Exchange admin and have no access to the exchange servers beyond my own inbox. Also I am not married to LINQ and would be happy to use other methods. I will appreciate your help.

NOTE: I just noticed that the above code is going through folder[1] twice. I can fix that, but it is not significantly affecting the time it takes.

Answer 1

No not use LINQ with OOM. Use Items.Find/FindNext or Items.Restrict .

You can also use Aplication.AdvancedSearch (keep in mind it is asynchronous).