If you are a programmer working with C#, you have likely encountered the need to convert an IEnumerable<T> to a List<T>. This is a common task when dealing with collections in C#, and fortunately, it is a straightforward process. In this article, we will discuss the steps involved in converting IEnumerable<T> to List<T> in C# and provide a simple guide to help you accomplish this task.
First, let's understand what IEnumerable<T> and List<T> are. IEnumerable<T> is an interface in C# that represents a collection of objects that can be iterated over. It provides methods for iterating through the collection and performing operations on each element. On the other hand, List<T> is a generic class that implements the IEnumerable<T> interface and provides additional features such as indexing and sorting. It is a dynamic array that can grow or shrink in size as needed.
Now that we have a basic understanding of the two types, let's look at how we can convert IEnumerable<T> to List<T>. The easiest way to do this is by using the ToList() method provided by LINQ (Language Integrated Query). This method takes an IEnumerable<T> as a parameter and returns a List<T> containing the same elements as the original collection. Let's take a look at an example:
IEnumerable<int> numbers = new List<int> { 1, 2, 3, 4, 5 };
List<int> numberList = numbers.ToList();
In the above code, we have an IEnumerable<int> containing a list of numbers. We then use the ToList() method to convert it to a List<int>. The result is a new List<int> with the same elements as the original collection. It's that simple!
But what if you want to convert a more complex type, such as a custom class, to a List<T>? In that case, you can use the LINQ Select() method to project each element of the IEnumerable<T> into a new form before converting it to a List<T>. Let's see how this works with an example:
public class Person
{
public string Name { get; set; }
public int Age { get; set; }
}
IEnumerable<Person> persons = new List<Person>
{
new Person { Name = "John", Age = 25 },
new Person { Name = "Mary", Age = 30 },
new Person { Name = "Mark", Age = 40 }
};
List<string> names = persons.Select(p => p.Name).ToList();
In the above code, we have an IEnumerable<Person> containing a list of Person objects. We use the Select() method to project each Person object into a string containing only the person's name. Then, using the ToList() method, we convert the result to a List<string>. This allows us to create a list of just the names from the original collection of Person objects.
In conclusion, converting IEnumerable<T> to List<T> in C# is a simple process that can be accomplished using the ToList() method provided by LINQ. It is a useful technique for working with collections and allows you to take advantage of the additional features provided by the List<T> class. Remember to use the Select() method when working with complex types to project the elements into the desired form before converting them to a list. We hope this guide has been helpful in understanding how to convert IEnumerable<T> to List<T> in C# and that you can now apply this knowledge in your own projects. Happy coding!
