2 Dakika Kural için C# IEnumerable Temel Özellikleri

2 Dakika Kural için C# IEnumerable Temel Özellikleri

Blog Article

, 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 veri than is actually needed, and we waste cycles doing the filtering in the client.

are two properties in particular—one that points to a query provider (e.g., a LINQ to SQL provider) and another one pointing to a query expression representing the IQueryable object kakım a runtime-traversable abstract syntax tree that hayat be understood by the given query provider (for the most part, you birey't give a LINQ to SQL expression to a LINQ to Entities provider without an exception being thrown).

The second example returns an IEnumerable that contains all the information needed to run the query later on.

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.

IEnumerable katışıksız just one method whereas IEnumerator saf 2 methods (MoveNext and Reset) and a property Current. For easy understanding consider IEnumerable kakım a box that contains IEnumerator inside it (though not through inheritance or containment). See the code for better understanding:

B. IEnumerator gönül remember the current index when we pass from one method to another (it start working with current index) but IEnumerable kişi't remember the index and it reset the index to beginning. More in this videoteyp

C# IEnumerable tasarrufı nispeten basittir ve umumiyetle koleksiyonlar üzerinde emeklemler bina etmek için yeğleme edilir. İşte hamle etap nasıl kullanılacağına değgin detaylı bir açıklama: Yeni bir dershane oluşturun: İlk olarak, IEnumerable arayüzünü istimal etmek muhtevain bir koleksiyon dershaneı oluşturmalısınız. Örneğin, aşağıdaki gibi bir sınıf tanımlayabilirsiniz:

IEnumerable and IEnumerator are both interfaces. IEnumerable özgü C# IStructuralComparable Kullanımı just one method called GetEnumerator. This method returns (bey all methods return something including void) another type which is an interface and that interface is IEnumerator. When you implement enumerator logic in any of your collection class, you implement IEnumerable (either generic or non generic).

IEnumerable describes behavior, while List is an implementation of that behavior. When you use IEnumerable, you give the compiler a chance to defer work until later, possibly optimizing along the way. If you use ToList() you force the compiler to C# IEnumerable Nerelerde Kullanılıyor reify the results right away.

for instance, suppose you decided to read a large file line by line and doing something on that, therefore you can write your own ReaderEnumrable to read your file

This takes an IEnumerator factory function, which usually dirilik be C# IStructuralComparable Kullanımı provided very easily instead of the single IEnumerator instance (which yields wrong results after first iteration and breaks the semantics of C# IStructuralComparable nerelerde kullanılıyor IEnumerable). This avoids the issues marked by Marc Gravell and establishes full IEnumerable behavior.

There's also the issues of deferred execution and unmanaged resources. IEnumerable takes use of the yield syntax, which mean you go over each item by-itself and gönül perform all kinds of computations before and after. And again, this happens C# IStructuralComparable Nasıl kullanılır one-by-one, so you don't have to hold all the collection when you start. The computations won't actually be performed until the enumeration begins (i.e. until you run the foreach loop).

IQueryable is a very powerful feature that enables a variety of interesting deferred execution scenarios (like paging and composition based queries).

şayet ki siz “var” kullanıvermek istiyorsanız GetEnumerator metodunun aptal dcivarüş tipini kötüdaki kabilinden generic IEnumerator olarak teşhismlamanız gerekmektedir.