IDictionary.Add(Object, Object) IDictionary.Add(Object, Object) IDictionary.Add(Object, Object) IDictionary.Add(Object, Object) Method

Definition

Adds an element with the provided key and value to the IDictionary object.

public:
 void Add(System::Object ^ key, System::Object ^ value);
public void Add (object key, object value);
abstract member Add : obj * obj -> unit
Public Sub Add (key As Object, value As Object)

Parameters

key
Object Object Object Object

The Object to use as the key of the element to add.

value
Object Object Object Object

The Object to use as the value of the element to add.

Exceptions

An element with the same key already exists in the IDictionary object.

Examples

The following code example demonstrates how to implement the Add method. This code example is part of a larger example provided for the IDictionary class.

public:
    virtual void Add(Object^ key, Object^ value)
    {
        // Add the new key/value pair even if this key already exists
        // in the dictionary.
        if (itemsInUse == items->Length)
        {
            throw gcnew InvalidOperationException
                ("The dictionary cannot hold any more items.");
        }
        items[itemsInUse++] = gcnew DictionaryEntry(key, value);
    }
public void Add(object key, object value) 
{
    // Add the new key/value pair even if this key already exists in the dictionary.
    if (ItemsInUse == items.Length)
        throw new InvalidOperationException("The dictionary cannot hold any more items.");
    items[ItemsInUse++] = new DictionaryEntry(key, value);
}
Public Sub Add(ByVal key As Object, ByVal value As Object) Implements IDictionary.Add

    ' Add the new key/value pair even if this key already exists in the dictionary.
    If ItemsInUse = items.Length Then
        Throw New InvalidOperationException("The dictionary cannot hold any more items.")
    End If
    items(ItemsInUse) = New DictionaryEntry(key, value)
    ItemsInUse = ItemsInUse + 1
End Sub

Remarks

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

Implementations can vary in whether they allow the key to be null.

Applies to

See Also