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; }
/** @property */
public final Object get_Item (Object key)

/** @property */
public final void set_Item (Object key, Object value)

Not applicable.



The key of the value to get or set.

Property Value

The value associated with the specified key. If the specified key is not found, attempting to get it returns a null reference (Nothing in Visual Basic), and attempting to set it creates a new element using the specified key.

Exception typeCondition


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 a null reference (Nothing in Visual Basic), but a value can be. To distinguish between a null reference (Nothing in Visual Basic) that is returned because the specified key is not found and a null reference (Nothing in Visual Basic) that is returned because the value of the specified key is a null reference (Nothing in Visual Basic), 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"))

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

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