Determines whether the IDictionary object contains an element with the specified key.
Function Contains ( _ key As Object _ ) As Boolean
Dim instance As IDictionary Dim key As Object Dim returnValue As Boolean returnValue = instance.Contains(key)
bool Contains( Object key )
bool Contains( Object^ key )
function Contains( key : Object ) : boolean
key is nullNothingnullptra null reference (Nothing in Visual Basic).
Implementations can vary in whether they allow the key to be nullNothingnullptra null reference (Nothing in Visual Basic).
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.
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 Function Contains(ByVal key As Object) As Boolean Implements IDictionary.Contains Dim index As Integer Return TryGetIndexOfKey(key, index) End Function
public bool Contains(object key) { Int32 index; return TryGetIndexOfKey(key, out index); }
public: virtual bool Contains(Object^ key) { int index; return TryGetIndexOfKey(key, &index); }
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