Create an Opportunity linked to a Business Contact

  private void CreateOpportunityWithBusinessContact()
        {
        Outlook.ApplicationClass _app = new Outlook.ApplicationClass();
        Outlook.Application olApp = (Outlook.Application)_app;
        Outlook.NameSpace olNameSpace = _app.GetNamespace("MAPI");
        Outlook.Folders folders = olNameSpace.Session.Folders;
        Outlook.Folder bcmRootFolder = (Outlook.Folder)folders["Business Contact Manager"];

        Outlook.Folder contacts = (Outlook.Folder)bcmRootFolder.Folders["Business Contacts"];
        
        Outlook.ContactItem newContact =
        (Outlook.ContactItem)contacts.Items.Add("IPM.Contact.BCM.Contact");

        newContact.FullName = "John Smith";
        newContact.FileAs = "John";
        newContact.Save();

        string contactEntryID = newContact.EntryID;

        Outlook.Folder opportunities = (Outlook.Folder)bcmRootFolder.Folders["Opportunities"];
        Outlook.TaskItem newOpportunity =
        (Outlook.TaskItem)opportunities.Items.Add("IPM.Task.BCM.Opportunity");
        newOpportunity.Subject = "Sales Opp with John Smith";

        if (newOpportunity.UserProperties["Account Name"] == null)
        {
            Outlook.UserProperty userProp = newOpportunity.UserProperties.Add("Parent Entity EntryID", Microsoft.Office.Interop.Outlook.OlUserPropertyType.olText, false, false);
            userProp.Value = contactEntryID;
        }

        newOpportunity.Save();

    }

  Sub CreateOpportunityWithBusinessContact()
Dim olApp As Outlook.Application
Dim objNS As Outlook.NameSpace
Dim olFolders As Outlook.Folders
Dim bcmRootFolder As Outlook.Folder
Dim bcmContactsFldr As Outlook.Folder
Dim bcmOppFolder As Outlook.Folder
Dim newContact As Outlook.ContactItem
Dim newOpportunity As Outlook.TaskItem
Set olApp = CreateObject("Outlook.Application")
Set objNS = olApp.GetNamespace("MAPI")
Set olFolders = objNS.Session.Folders
Set bcmRootFolder = olFolders("Business Contact Manager")
Set bcmContactsFldr = bcmRootFolder.Folders("Business Contacts")
Set bcmOppFolder = bcmRootFolder.Folders("Opportunities")
Set newContact = bcmContactsFldr.Items.Add("IPM.Contact.BCM.Contact")
newContact.FullName = "John Smith"
newContact.FileAs = "John Smith"
newContact.Email1Address = "someone@example.com"
newContact.Save
Set newOpportunity = bcmOppFolder.Items.Add("IPM.Task.BCM.Opportunity")
newOpportunity.Subject = "Opportunity For Wide World Importers to enter into Retail Field"
If (newOpportunity.UserProperties("Parent Entity EntryID") Is Nothing) Then
Set userProp = newOpportunity.UserProperties.Add("Parent Entity EntryID", olText, False, False)
userProp.Value = newContact.EntryID
End If
newOpportunity.Save
Set newOpportunity = Nothing
Set newContact = Nothing
Set bcmOppFolder = Nothing
Set bcmContactsFldr = Nothing
Set bcmRootFolder = Nothing
Set olFolders = Nothing
Set objNS = Nothing
Set olApp = Nothing
End Sub