// This populates the dgGroupActivities data grid with all the activities that a particular group is signed up to participate in.
private void populateGroupActivities()
{
var allActivities = _activityManager.RetrieveAllGroupActivities();
var groupActivities = _groupManager.RetrieveActivitiesByGroupID(_groupID);
for (int i = 0; i < allActivities.Count; i++)
{
for (int j = 0; j < groupActivities.Count; j++)
{
if (allActivities[i].ActivityID == groupActivities[j].ActivityID)
{
allActivities.Remove(allActivities[i]);
}
}
}
dgGroupActivities.ItemsSource = allActivities;
}