Get external users for a site collection

GetExternalUsersForSiteCollection.cs

string tenantAdminUrl = "https://yourtenant-admin.sharepoint.com/";
string userName = "[email protected]";
string userPassword = "password";
string siteCollectionUrl = "https://yourtenant.sharepoint.com/sites/teamsite/";

//Open the Tenant Administration Context with the Tenant Admin Url
using (var tenantContext = new ClientContext(tenantAdminUrl))
{
	//Authenticate with a Tenant Administrator
	var passWord = new SecureString();
	foreach (char c in userPassword.ToCharArray()) passWord.AppendChar(c);
	tenantContext.Credentials = new SharePointOnlineCredentials(userName, passWord);

	var o365Tenant = new Office365Tenant(tenantContext);

	//initalize varables to going through the paged results
	int position = 0;
	bool hasMore = true;
	while (hasMore)
	{
		//get external users 50 at a time (this is the limit and why we are paging)
		var externalUsers = o365Tenant.GetExternalUsersForSite(siteCollectionUrl, position, 50, String.Empty, SortOrder.Descending);

		tenantContext.Load(externalUsers, i => i.TotalUserCount);
		tenantContext.Load(externalUsers, i => i.ExternalUserCollection);
		tenantContext.ExecuteQuery();

		//convert each external user to our own entity
		foreach (var extUser in externalUsers.ExternalUserCollection)
		{
			position++;

			Console.WriteLine(extUser.DisplayName + " " + extUser.UniqueId + " " +
				extUser.AcceptedAs + " " + extUser.InvitedAs + " " + extUser.InvitedBy + extUser.WhenCreated);
		}

		//determine if we have more pages to process
		hasMore = (externalUsers.TotalUserCount > position);
	}
}