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OrderedDictionary.Item Property (Object)

Gets or sets the value with the specified key.

Namespace:  System.Collections.Specialized
Assembly:  System (in System.dll)

public Object this[
	Object key
] { get; set; }

Parameters

key
Type: System.Object

The key of the value to get or set.

Property Value

Type: System.Object
The value associated with the specified key. If the specified key is not found, attempting to get it returns null, and attempting to set it creates a new element using the specified key.

Implements

IDictionary.Item

ExceptionCondition
NotSupportedException

The property is being set and the OrderedDictionary collection is read-only.

This property allows you to access a specific element in the collection by using the following syntax: myCollection[key].

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

A key cannot be null, but a value can be. To distinguish between null that is returned because the specified key is not found and null that is returned because the value of the specified key is null, use the Contains method to determine if the key exists in the OrderedDictionary.

The following code example demonstrates the modification of an OrderedDictionary collection. In this example, the Item property is used to modify the dictionary entry with the key "testKey2". This code is part of a larger code example that can be viewed at OrderedDictionary.

// Modifying the OrderedDictionary 
if (!myOrderedDictionary.IsReadOnly)
{
    // Insert a new key to the beginning of the OrderedDictionary
    myOrderedDictionary.Insert(0, "insertedKey1", "insertedValue1");

    // Modify the value of the entry with the key "testKey2"
    myOrderedDictionary["testKey2"] = "modifiedValue";

    // Remove the last entry from the OrderedDictionary: "testKey3"
    myOrderedDictionary.RemoveAt(myOrderedDictionary.Count - 1);

    // Remove the "keyToDelete" entry, if it exists
    if (myOrderedDictionary.Contains("keyToDelete"))
    {
        myOrderedDictionary.Remove("keyToDelete");
    }
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, 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.

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