The ICollection<T> interface doesn’t specify anything about an order. The objects will be in the order specified by the object returned. For example, if you return the Values collection of a SortedDictionary, the objects will be in the the order defined by the dictionary’s comparer. If you need the method to return, by contract, a … Read more
First, I don’t understand why you are adding all the keys and values count times, Index is never used. I tried this example : var source = new BindingSource(); List<MyStruct> list = new List<MyStruct> { new MyStruct(“fff”, “b”), new MyStruct(“c”,”d”) }; source.DataSource = list; grid.DataSource = source; and that work pretty well, I get two … Read more
Basically the nongeneric interfaces came first, in .NET 1.0 and 1.1. Then when .NET 2.0 came out, the generic equivalents came out. Life would have been a lot simpler if generics had made it into .NET 1.0 🙂 In terms of implementing “only” IEnumerable<T> instead of both – you basically have to implement both, and … Read more
You can use LINQ for this:. var foo = myICollection.OfType<YourType>().FirstOrDefault(); // or use a query var bar = (from x in myICollection.OfType<YourType>() where x.SomeProperty == someValue select x) .FirstOrDefault();
Entity Framework would use ICollection<T> because it needs to support Add operations, which are not part of the IEnumerable<T> interface. Also note that you were using ICollection<T>, you were merely exposing it as the List<T> implementation. List<T> brings along with it IList<T>, ICollection<T>, and IEnumerable<T>. As for your change, exposing via the interface is a … Read more
Usually what you choose will depend on which methods you need access to. In general – IEnumerable<> (MSDN: http://msdn.microsoft.com/en-us/library/system.collections.ienumerable.aspx) for a list of objects that only needs to be iterated through, ICollection<> (MSDN: http://msdn.microsoft.com/en-us/library/92t2ye13.aspx) for a list of objects that needs to be iterated through and modified, List<> for a list of objects that needs … Read more