Collection<T>.Contains(T) Method
Definition
Important
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Determines whether an element is in the Collection<T>.
public:
virtual bool Contains(T item);public bool Contains (T item);abstract member Contains : 'T -> bool
override this.Contains : 'T -> boolPublic Function Contains (item As T) As BooleanParameters
- item
- T
The object to locate in the Collection<T>. The value can be null for reference types.
Returns
true if item is found in the Collection<T>; otherwise, false.
Implements
Remarks
If the Collection<T> object is created using the parameterless constructor, this method determines equality using the default equality comparer EqualityComparer<T>.Default for T, the type of values in the list. If type T does not implement the IEquatable<T> interface, the Equals method is used.
If the Collection object is created by passing an IList<T> object to the constructor, the Contains method will be determined by the IEqualityComparer<T> interface used by that IList<T> object.
This method performs a linear search; therefore, the average execution time is proportional to Count. That is, this method is an O(n) operation, where n is Count.
