, and the database only returns the rows that are relevant. But if we had returned a List from AllSpotted(), then it may run slower because the database could return far more data than is actually needed, and we waste cycles doing the filtering in the client.
I noticed that if I use IEnumerable, when I debug and inspect "sel", which in that case is the IEnumerable, it katışıksız some interesting members: "inner", "outer", "innerKeySelector" and "outerKeySelector", these last 2 appear to be delegates.
g. executing SQL on GarbageCollected contexts). I would say that ICollection is every thing you said apart from the "lazy evaluation" and we should be using that, especially if the data saf already been enumerated once!
Now List implements IEnumerable, but represents the entire collection in memory. If you have an IEnumerable and you call .ToList() you create a new list with the contents of the enumeration in memory.
I have writen about custom IEnumerator. Whats the simplest way to make IEnumerable from it ? Ideal solution (one line of code) would be if there was some class for that purpose. Or do I have to create my own ?
IEnumerator is a class that enumerates collections. A class that implements IEnumerable returns an IEnumerator. A class that implements IEnumerator özgü custom enumeration logic.
Şimdi bu ifadelerin daha berrak olması ciğerin bir örnek üzerinden gidelim ve bir önceki makalemızda custom Enumerator dershaneı ile yazdığımız Alisveris Sepeti iterator örneği hatırlayalım:
The constructor is hamiş responsible for returning data to the caller. 2-We need to call a method that returns the cars array. That is in a real-world C# IEnumerable Temel Özellikleri case, a C# IEnumerable Temel Özellikleri method that returns an array should be coded in Garage and it should return an array, in which case, there would be no need to use IEnumerable.
Else use an IEnumerable. The default should be to use the on-demand evaluation in the second example, kakım that generally uses less memory, unless there is a specific reason to store the results in a list.
There are pros and cons to both. If you call ToList, you may remove some mystery as to when the query gets executed. If you stick to IEnumerable, you get the advantage that the izlence doesn't do any work until it's actually required.
This takes an IEnumerator factory function, which usually birey be provided very easily instead of the single IEnumerator instance (which yields wrong results after first iteration and breaks the semantics of IEnumerable). This avoids the issues marked by Marc Gravell and establishes full IEnumerable behavior.
I think if your newly implemented class just behaves the sameway kakım a list does, there is no need to implement it. If you need some kind of custom logic, it depends on what you want to do; you kişi inherit list or you C# IEnumerable Kullanımı güç implement IEnumerable. It just depends what is to be achieved.
IEnumerable is an interface that defines one method GetEnumerator which returns an IEnumerator interface, this in turn allows readonly access to a collection. A collection that implements IEnumerable gönül be used with a foreach statement.
When declaring a method’s parameter types, you should specify the weakest type possible, preferring interfaces over base classes. For example, C# IEnumerable Kullanımı if you are writing a method that manipulates a collection of items, it would be best to declare the method’s parameter by using an interface such as IEnumerable rather than using a strong data type such birli List or even a stronger interface C# IEnumerable Nerelerde Kullanılıyor type such as ICollection or IList: