在C＃中获取联系人组的Outlook联系人

Question

Following code works fine to get outlook contact

Microsoft.Office.Interop.Outlook.Items OutlookItems;
Microsoft.Office.Interop.Outlook.Application outlookObj = new Microsoft.Office.Interop.Outlook.Application();
MAPIFolder Folder_Contacts = (MAPIFolder)outlookObj.Session.GetDefaultFolder(OlDefaultFolders.olFolderContacts);
OutlookItems = Folder_Contacts.Items;

foreach (ContactItem contact in OutlookItems)
 {
     Console.WriteLine("FirstName " + contact.FirstName);
 }

but when i create a group in outlook and add contact in that group and run this code ,this generates an error

Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Interop.Outlook.ContactItem'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00063021-0000-0000-C000-000000000046}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).

why this is happening and how to solve it???

Answer 1

The OutlookItems contains both group and contacts, and you're interested only in contacts, so get them like this:

  foreach (var item in OutlookItems) {
    var contact = item as ContactItem;
    if (contact != null) {
      Console.WriteLine("FirstName " + contact.FirstName);
    }
  }