public static EntityCollection <TElement> CreateCollection <T, TElement>(this T entity, Expression <Func <T, EntityCollection <TElement> > > expr, params TElement[] items)
where T : EntityObject
where TElement : EntityObject
{
if (expr.Body.NodeType != ExpressionType.MemberAccess)
{
throw new ArgumentException("Expression is not correct.", "expr");
}
var member = ((MemberExpression)expr.Body).Member;
PropertyInfo pi = member as PropertyInfo;
if (pi == null)
{
throw new ArgumentException("Expression is not correct.", "expr");
}
EdmRelationshipNavigationPropertyAttribute attribute = (EdmRelationshipNavigationPropertyAttribute)Attribute.GetCustomAttribute(pi, typeof(EdmRelationshipNavigationPropertyAttribute));
EntityCollection <TElement> result = new EntityCollection <TElement>();
RelationshipManager rm = RelationshipManager.Create(entity);
rm.InitializeRelatedCollection(attribute.RelationshipName, attribute.TargetRoleName, result);
foreach (var item in items)
{
result.Add(item);
}
return(result);
}