VSTO Outlook - Contact iteration is SO SLOW!

I'm working on an outlook add-in and I have a dialog window that allows the user to select contacts. I havent been able to find a way to use the outlook contact window so I am looping through the ContactFolder.Items and doing my work that way.

The problem is that I have to handle up to 70K contacts. I tried multi-threading and many other things but it is just so slow. It takes 15 seconds to load 30k contacts.

I can lo开发者_StackOverflow中文版ad and bind 500k POCO objects in milliseconds but when I need to get the contact items from outlook it just takes forever. The problem seems to be when you actually need to get a property from the contactitem it has to fetch it from the database or something. Is there a contact cache I can pull from? I only need Display and Email, nothing else. An ID would be nice but I don't need it.

Can someone please tell me a better way of getting contacts from outlook or at least tell me how to open the outlook contact selection window? I was able to find code to open it but it wont let me because I'm showing a modal dialog and it wont open if there is a modal open.

Answer:

Microsoft.Office.Interop.Outlook.NameSpace ns = Globals.ThisAddIn.Application.GetNamespace("MAPI");
  Microsoft.Office.Interop.Outlook.MAPIFolder contactsFld = ns.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderContacts);

  Microsoft.Office.Interop.Outlook.Table tb = ns.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderContacts).GetTable(null, Microsoft.Office.Interop.Outlook.OlItemType.olContactItem);

  tb.Columns.RemoveAll();
  tb.Columns.Add("Email1Address");
  tb.Columns.Add("FullName");

  object[,] otb = tb.GetArray(100000) as object[,];
  int len = otb.GetUpperBound(0);

  for (int i = 0; i < len; i++)
  {
    if (otb[i, 0] == null)
    {
      continue;
    }
    Contacts.Add(new ContactItem() { ContactDisplay = otb[i, 1].ToString(), ContactEmail = otb[i, 0].ToString() });

  }

This loads in less than a second which is fast enough to put it back on the UI thread.