SortedList.Add Method

Adds an element with the specified key and value into the SortedList.

Namespace: System.Collections.Generic
Assembly: System (in system.dll)

public void Add (
	TKey key,
	TValue value
public final void Add (
	TKey key, 
	TValue value
public final function Add (
	key : TKey, 
	value : TValue
Not applicable.



The key of the element to add.


The value of the element to add. The value can be a null reference (Nothing in Visual Basic) for reference types.

Exception typeCondition


key is a null reference (Nothing in Visual Basic).


An element with the same key already exists in the SortedList.

A key cannot be a null reference (Nothing in Visual Basic), but a value can be, if the type of values in the sorted list, TValue, is a reference type.

You can also use the Item property to add new elements by setting the value of a key that does not exist in the SortedList; for example, myCollection["myNonexistentKey"] = myValue. However, if the specified key already exists in the SortedList, setting the Item property overwrites the old value. In contrast, the Add method does not modify existing elements.

If Count already equals Capacity, the capacity of the SortedList is increased by automatically reallocating the internal array, and the existing elements are copied to the new array before the new element is added.

This method is an O(n) operation for unsorted data, where n is Count. It is an O(log n) operation if the new element is added at the end of the list. If insertion causes a resize, the operation is O(n).

The following code example creates an empty SortedList of strings with string keys and uses the Add method to add some elements. The example demonstrates that the Add method throws an ArgumentException when attempting to add a duplicate key.

This code example is part of a larger example provided for the SortedList class.

// Create a new sorted list of strings, with string
// keys.
SortedList<string, string> openWith = 
    new SortedList<string, string>();

// Add some elements to the list. There are no 
// duplicate keys, but some of the values are duplicates.
openWith.Add("txt", "notepad.exe");
openWith.Add("bmp", "paint.exe");
openWith.Add("dib", "paint.exe");
openWith.Add("rtf", "wordpad.exe");

// The Add method throws an exception if the new key is 
// already in the list.
    openWith.Add("txt", "winword.exe");
catch (ArgumentException)
    Console.WriteLine("An element with Key = \"txt\" already exists.");

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0

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