IDictionary.Contains(Object) IDictionary.Contains(Object) IDictionary.Contains(Object) IDictionary.Contains(Object) Method


Determines whether the IDictionary object contains an element with the specified key.

 bool Contains(System::Object ^ key);
public bool Contains (object key);
abstract member Contains : obj -> bool
Public Function Contains (key As Object) As Boolean


Object Object Object Object

The key to locate in the IDictionary object.


true if the IDictionary contains an element with the key; otherwise, false.



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

    virtual bool Contains(Object^ key)
        int index;
        return TryGetIndexOfKey(key, &index);
public bool Contains(object key)
   Int32 index;
   return TryGetIndexOfKey(key, out index);
Public Function Contains(ByVal key As Object) As Boolean Implements IDictionary.Contains
    Dim index As Integer
    Return TryGetIndexOfKey(key, index)
End Function


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

Starting with the .NET Framework 2.0, this method uses the collection's objects' Equals and CompareTo methods on item to determine whether item exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item parameter on the objects in the collection.

Applies to