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IDictionary.Contains Method

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

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

bool Contains(
	Object key
)

Parameters

key
Type: System.Object

The key to locate in the IDictionary object.

Return Value

Type: System.Boolean
true if the IDictionary contains an element with the key; otherwise, false.

ExceptionCondition
ArgumentNullException

key is null.

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.

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 bool Contains(object key)
{
   Int32 index;
   return TryGetIndexOfKey(key, out index);
}

.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

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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