Distinct(TSource) Method (IQueryable(TSource), IEqualityComparer(TSource))

Queryable::Distinct<TSource> Method (IQueryable<TSource>^, IEqualityComparer<TSource>^)


Returns distinct elements from a sequence by using a specified IEqualityComparer<T> to compare values.

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)

generic<typename TSource>
static IQueryable<TSource>^ Distinct(
	IQueryable<TSource>^ source,
	IEqualityComparer<TSource>^ comparer


Type: System.Linq::IQueryable<TSource>^

The IQueryable<T> to remove duplicates from.

Type: System.Collections.Generic::IEqualityComparer<TSource>^

An IEqualityComparer<T> to compare values.

Return Value

Type: System.Linq::IQueryable<TSource>^

An IQueryable<T> that contains distinct elements from source.

Type Parameters


The type of the elements of source.

Exception Condition

source or comparer is null.

The Distinct<TSource>(IQueryable<TSource>^, IEqualityComparer<TSource>^) method generates a MethodCallExpression that represents calling Distinct<TSource>(IQueryable<TSource>^, IEqualityComparer<TSource>^) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression^) method of the IQueryProvider represented by the Provider property of the source parameter.

The query behavior that occurs as a result of executing an expression tree that represents calling Distinct<TSource>(IQueryable<TSource>^, IEqualityComparer<TSource>^) depends on the implementation of the type of the source parameter. The expected behavior is that it returns an unordered sequence of the unique items in source by using comparer to compare values.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1
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