List<T>.Item Property
Gets or sets the element at the specified index.
Namespace: System.Collections.Generic
Assembly: mscorlib (in mscorlib.dll)
Parameters
- index
- Type: System.Int32
The zero-based index of the element to get or set.
Implements
IList<T>.ItemIReadOnlyList<T>.Item
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | index is less than 0. -or- index is equal to or greater than Count. |
List<T> accepts null as a valid value for reference types and allows duplicate elements.
This property provides the ability to access a specific element in the collection by using the following syntax: myCollection[index].
Retrieving the value of this property is an O(1) operation; setting the property is also an O(1) operation.
The following code example demonstrates the Item property (the indexer in C#) and various other properties and methods of the List<T> generic class. After the list has been created and populated using the Add method, an element is retrieved and displayed using the Item property.
 Note |
|---|
Visual Basic, C#, and C++ all have syntax for accessing the Item property without using its name. Instead, the variable containing the List<T> is used as if it were an array. |
The C# language uses the this keyword to define the indexers instead of implementing the Item property. Visual Basic implements Item as a default property, which provides the same indexing functionality.
For a code example that uses the Item property to set the value of a list element, see AsReadOnly.
using System; using System.Collections.Generic; public class Example { public static void Main() { List<string> dinosaurs = new List<string>(); Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity); dinosaurs.Add("Tyrannosaurus"); dinosaurs.Add("Amargasaurus"); dinosaurs.Add("Mamenchisaurus"); dinosaurs.Add("Deinonychus"); dinosaurs.Add("Compsognathus"); Console.WriteLine(); foreach(string dinosaur in dinosaurs) { Console.WriteLine(dinosaur); } Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity); Console.WriteLine("Count: {0}", dinosaurs.Count); Console.WriteLine("\nContains(\"Deinonychus\"): {0}", dinosaurs.Contains("Deinonychus")); Console.WriteLine("\nInsert(2, \"Compsognathus\")"); dinosaurs.Insert(2, "Compsognathus"); Console.WriteLine(); foreach(string dinosaur in dinosaurs) { Console.WriteLine(dinosaur); } Console.WriteLine("\ndinosaurs[3]: {0}", dinosaurs[3]); Console.WriteLine("\nRemove(\"Compsognathus\")"); dinosaurs.Remove("Compsognathus"); Console.WriteLine(); foreach(string dinosaur in dinosaurs) { Console.WriteLine(dinosaur); } dinosaurs.TrimExcess(); Console.WriteLine("\nTrimExcess()"); Console.WriteLine("Capacity: {0}", dinosaurs.Capacity); Console.WriteLine("Count: {0}", dinosaurs.Count); dinosaurs.Clear(); Console.WriteLine("\nClear()"); Console.WriteLine("Capacity: {0}", dinosaurs.Capacity); Console.WriteLine("Count: {0}", dinosaurs.Count); } } /* This code example produces the following output: Capacity: 0 Tyrannosaurus Amargasaurus Mamenchisaurus Deinonychus Compsognathus Capacity: 8 Count: 5 Contains("Deinonychus"): True Insert(2, "Compsognathus") Tyrannosaurus Amargasaurus Compsognathus Mamenchisaurus Deinonychus Compsognathus dinosaurs[3]: Mamenchisaurus Remove("Compsognathus") Tyrannosaurus Amargasaurus Mamenchisaurus Deinonychus Compsognathus TrimExcess() Capacity: 5 Count: 5 Clear() Capacity: 5 Count: 0 */
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
