ContainsKey Method
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IReadOnlyDictionary(Of TKey, TValue).ContainsKey Method (TKey)

.NET Framework (current version)
 

Determines whether the read-only dictionary contains an element that has the specified key.

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

Function ContainsKey (
	key As TKey
) As Boolean

Parameters

key
Type: TKey

The key to locate.

Return Value

Type: System.Boolean

true if the read-only dictionary contains an element that has the specified key; otherwise, false.

Exception Condition
ArgumentNullException

key is null.

Implementations can vary in how they determine the equality of objects; for example, the class that implements IReadOnlyDictionary(Of TKey, TValue) might use the Comparer(Of T).Default property, or it might implement the IComparer(Of T) method.

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

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 4.5
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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