can someone explain me the difference between IList and List ?

Abhishek Yadav

2y818C#

i used IList with my day to day linq quaries but curious to know in simple words what is the diffrence between them i mean List and IList ?

3 Replies

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Jayraj Chhaya2y ago
Accepted answer
Hi Abhishek Yadav,

List and IList are related but have distinct differences. List is a class that implements IList, which is an interface. List provides more functionality and is mutable, allowing you to add, remove, and modify elements. On the other hand, IList is an interface that defines properties and methods for collections.

Where to Use:
- List: Use List when you need a dynamic array that can grow or shrink in size.
- IList: Use IList when you want to work with collections in a more generic way without specifying a particular implementation.
Real-Life Example:

Imagine you have a shopping cart. You would use a List to store the items because you need to add, remove, or update items dynamically. However, if you have a method that accepts any collection type, you would use IList as a parameter type.

In summary, List is mutable and provides more features, while IList is more generic and allows flexibility in working with different collection types.
Sam Hobbs2y ago
It is easy to understand the difference when we understand what interfaces are. An interface has methods defined but no implementation for the methods. It is not possible to declare (allocate using the new operator) an interface. Use of an interface requires defining a class that inherits the interface and that implements the methods. Or an interface can be used to specify that any such class can be used.

Note that there are the following in the System.Collections.Generic namespace.

IList Interface
https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.ilist-1?view=net-8.0

List Class
https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1?view=net-8.0

And the following in the System.Collections namespace.

IList Interface
https://learn.microsoft.com/en-us/dotnet/api/system.collections.ilist?view=net-8.0

ArrayList Class
https://learn.microsoft.com/en-us/dotnet/api/system.collections.arraylist?view=net-8.0
Abhishek Yadav2y ago
Jayraj Chhaya beautifull explantion brother