Parameters

key

The key to locate in the current instance.

Returns

true if the current instance contains key; otherwise, false.

Exceptions

Type	Reason
ArgumentNullException	key is null.

Remarks

Note: This method is implemented to support the IDictionary interface.

Operation

As described above.

This method is equivalent to Hashtable.ContainsKey(object).

Note: For the default implementation, this method has a constant (O(1)) lookup time.

Requirements

Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0