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DictionaryBase.IDictionary.Add Method

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

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

private abstract Add : 
        key:Object * 
        value:Object -> unit  
private override Add : 
        key:Object * 
        value:Object -> unit


Type: System.Object

The key of the element to add.

Type: System.Object

The value of the element to add.


IDictionary.Add(Object, Object)


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


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


The DictionaryBase is read-only.


The DictionaryBase has a fixed size.

An object that has no correlation between its state and its hash code value should typically not be used as the key. For example, String objects are better than StringBuilder objects for use as keys.

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

This method is an O(1) operation.

The following code example implements the DictionaryBase class and uses that implementation to create a dictionary of String keys and values that have a Length of 5 characters or less.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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