How to: Get Members of an Exchange Distribution List
This example prompts the user to select an Exchange distribution list from the Select Names dialog box and expands the distribution list to display its members.
This code sample calls the GetExchangeDistributionListMembers method of the ExchangeDistributionList object to get an AddressEntries collection that contains all the members of the list. Because distribution lists can be nested inside another distribution list, the returned AddressEntries collection can represent any type of Exchange AddressEntry object.
Expanding distribution lists can create a performance burden on an Exchange server, so use the GetExchangeDistributionListMembers method cautiously. Expect that your code will be slow when it expands large distribution lists.
To obtain the members of a distribution list, the user must be connected to an Exchange server and online.
If you use Visual Studio to test this code example, you must first add a reference to the Microsoft Outlook 15.0 Object Library component and specify the Outlook variable when you import the Microsoft.Office.Interop.Outlook namespace. The Imports or using statement must not occur directly before the functions in the code example but must be added before the public Class declaration. The following lines of code show how to do the import and assignment in Visual Basic and C#.
Private Sub GetDistributionListMembers() Dim snd As Outlook.SelectNamesDialog = _ Application.Session.GetSelectNamesDialog() Dim addrLists As Outlook.AddressLists = _ Application.Session.AddressLists For Each addrList As Outlook.AddressList In addrLists If addrList.Name = "All Groups" Then snd.InitialAddressList = addrList Exit For End If Next snd.NumberOfRecipientSelectors = _ Outlook.OlRecipientSelectors.olShowTo snd.ToLabel = "D/L" snd.ShowOnlyInitialAddressList = True snd.AllowMultipleSelection = False snd.Display() If (snd.Recipients.Count > 0) Then Dim addrEntry As Outlook.AddressEntry = _ snd.Recipients(1).AddressEntry If (addrEntry.AddressEntryUserType = _ Outlook.OlAddressEntryUserType. _ olExchangeDistributionListAddressEntry) Then Dim exchDL As Outlook.ExchangeDistributionList = _ addrEntry.GetExchangeDistributionList() Dim addrEntries As Outlook.AddressEntries = _ exchDL.GetExchangeDistributionListMembers() If Not (addrEntries Is Nothing) Then For Each exchDLMember As _ Outlook.AddressEntry In addrEntries Debug.WriteLine(exchDLMember.Name) Next End If End If End If End Sub