how to replace MailItem in outlook c#

Question

I'm writing a stand-alone program to copy multiple PSTs to a single, new PST. When there are duplicates of an email, I'd like just 1 copy, not all of them.

As it stands, my code is:

if (item is Outlook.MailItem)
{
    Outlook.MailItem i = item as Outlook.MailItem;
    Outlook.MailItem iCopy = i.Copy();
    iCopy.Move(targetMAPIFolder);
}

Outlook is able to produce the desired results manually by choosing: File > Open > Import > Import from another program or file > Outlook data file > Replace duplicates with items imported.

Thanks for your help!

Answer 1

You main problem here is how to determine what is a duplicate. If you were moving them within a single .PST you could compare the MailItem.Id property as this is unique in a single PST. As your moving from one pst to another you probably want to review which properties you deem as 'unique' on the mail item and compare them. (You could even use a hash value if you wanted). As an example -

var hash = String.Format("{0}{1}{2}{3}", item.To, item.From, item.CC, item.Subject, item.Body).GetHashCode();

Should give you a hash value to compare against the existing items in your target PST.

Or simply just compare the properties you deem would show a duplicate

Example -

private bool CheckIsDuplicate(MailItem item)
{
    //load the target pst
    Microsoft.Office.Interop.Outlook.Application app = new Microsoft.Office.Interop.Outlook.Application();
   Microsoft.Office.Interop.Outlook.NameSpace outlookNs = app.GetNamespace("MAPI");
   outlookNs.AddStore(@"D:\pst\Test.pst");
   Microsoft.Office.Interop.Outlook.MAPIFolder emailFolder = outlookNs.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderSentMail);

   //check for your mail item in the repository
   var duplicateItem = (
       from email in
       emailFolder.Items.OfType<MailItem>()
       where //here you could try a number of things a hash value of the properties or try using the item.I
       email.SenderName == item.SenderName &&
       email.To == item.To &&
       email.Subject == item.Subject &&
       email.Body == item.Body
       select email
           ).FirstOrDefault();

       return duplicateItem != null;
}