OrderedDictionary.Item[] Property

Definition

Namespace:

System.Collections.Specialized

Assembly:

System.Collections.Specialized.dll

Gets or sets the specified value.

Overloads

Item[Int32]	Gets or sets the value at the specified index.
Item[Object]	Gets or sets the value with the specified key.

Item[Int32]

Source:

OrderedDictionary.cs

Gets or sets the value at the specified index.

public:
 property System::Object ^ default[int] { System::Object ^ get(int index); void set(int index, System::Object ^ value); };

public object? this[int index] { get; set; }

member this.Item(int) : obj with get, set

Default Public Property Item(index As Integer) As Object

Parameters

index

Int32

The zero-based index of the value to get or set.

Property Value

Object

The value of the item at the specified index.

Implements

Item[Int32]

Exceptions

NotSupportedException

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

ArgumentOutOfRangeException

index is less than zero.

-or-

index is equal to or greater than Count.

Remarks

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

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.

Item[Object]

Source:

OrderedDictionary.cs

Gets or sets the value with the specified key.

public:
 property System::Object ^ default[System::Object ^] { System::Object ^ get(System::Object ^ key); void set(System::Object ^ key, System::Object ^ value); };

public object? this[object key] { get; set; }

member this.Item(obj) : obj with get, set

Default Public Property Item(key As Object) As Object

Parameters

key

Object

The key of the value to get or set.

Property Value

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

Item[Object]

Exceptions

NotSupportedException

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

Examples

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");
    }
}

// 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");
    }
}

' Modifying the OrderedDictionary
If Not myOrderedDictionary.IsReadOnly Then

    ' 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")) Then
        myOrderedDictionary.Remove("keyToDelete")
    End If
End If

Remarks

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.