Dictionary<TKey,TValue>.KeyCollection.ICollection<TKey>.Contains Method

Definition

Determines whether the ICollection<T> contains a specific value.

bool ICollection<TKey>.Contains (TKey item);

Parameters

item
TKey

The object to locate in the ICollection<T>.

Returns

true if item is found in the ICollection<T>; otherwise, false.

Implements

Remarks

Implementations can vary in how they determine equality of objects; for example, List<T> uses Default, whereas, Dictionary<TKey,TValue> allows the user to specify the IComparer<T> implementation to use for comparing keys.

This method is an O(1) operation.

Applies to

Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.6, 2.0, 2.1
UWP 10.0