/// <summary>
/// Workaround for EF BUG: https://entityframework.codeplex.com/workitem/2074
/// </summary>
static void WorkaroundForEntityFrameworkLazyLoadingBug(MemberExpression field, FieldAccessor accessor)
{
var maybeLazyLoaded =
(field.Member is PropertyInfo) &&
((PropertyInfo)field.Member).GetAccessors().Any(method => method.Attributes.HasFlag(MethodAttributes.Virtual));
if (maybeLazyLoaded)
{
var get = accessor.Get;
var set = accessor.Set;
accessor.Set =
(t, v) =>
{
get(t);
set(t, v);
};
}
}
static FieldAccessor Compile(Type type, string fieldName)
{
var target = Expression.Parameter(typeof(object));
var value = Expression.Parameter(typeof(object));
var field = Expression.PropertyOrField(Expression.Convert(target, type), fieldName);
var get =
CanReadMember(field.Member)
? Expression.Lambda<Func<object, object>>(Expression.Convert(field, typeof(object)), target).Compile()
: t => { throw new NotSupportedException(); };
var set =
CanWriteMember(field.Member)
? Expression.Lambda<Action<object, object>>(Expression.Assign(field, Expression.Convert(value, field.Type)), target, value).Compile()
: (t, v) => { throw new NotSupportedException(); };
var accessor =
new FieldAccessor
{
Type = field.Type,
Get = get,
Set = set,
};
WorkaroundForEntityFrameworkLazyLoadingBug(field, accessor);
return accessor;
}
