IDictionary.Contains(Object) Method
Definition
Important
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Determines whether the IDictionary object contains an element with the specified key.
public:
bool Contains(System::Object ^ key);public bool Contains (object key);abstract member Contains : obj -> boolPublic Function Contains (key As Object) As BooleanParameters
- key
- Object
The key to locate in the IDictionary object.
Returns
true if the IDictionary contains an element with the key; otherwise, false.
Exceptions
key is null.
Examples
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.
public:
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
Remarks
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.
