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Queryable.Distinct(TSource) Method (IQueryable(TSource))

Returns distinct elements from a sequence by using the default equality comparer to compare values.

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

static member Distinct : 
        source:IQueryable<'TSource> -> IQueryable<'TSource> 

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Linq.IQueryable(TSource)

The IQueryable(T) to remove duplicates from.

Return Value

Type: System.Linq.IQueryable(TSource)
An IQueryable(T) that contains distinct elements from source.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable(TSource). When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

ExceptionCondition
ArgumentNullException

source is a null reference (Nothing in Visual Basic).

The Distinct(TSource)(IQueryable(TSource)) method generates a MethodCallExpression that represents calling Distinct(TSource)(IQueryable(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)) 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.

The following code example demonstrates how to use Distinct(TSource)(IQueryable(TSource)) to return distinct elements from a sequence.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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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