Queryable::Aggregate<TSource, TAccumulate, TResult> Method (IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate, TSource, TAccumulate>>, Expression<Func<TAccumulate, TResult>>)
Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.
Assemblies: System.Linq.Queryable (in System.Linq.Queryable.dll)
System.Core (in System.Core.dll)
[ExtensionAttribute] public: generic<typename TSource, typename TAccumulate, typename TResult> static TResult Aggregate( IQueryable<TSource>^ source, TAccumulate seed, Expression<Func<TAccumulate, TSource, TAccumulate>^>^ func, Expression<Func<TAccumulate, TResult>^>^ selector )
The type of the elements of source.
The type of the accumulator value.
The type of the resulting value.
- Type: System.Linq::IQueryable<>
A sequence to aggregate over.
The initial accumulator value.
- Type: System.Linq.Expressions::Expression<Func<, , >>
An accumulator function to invoke on each element.
The transformed final accumulator value.
Usage NoteIn Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<>. 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).
This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T, TResult> types. For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.
The method generates a MethodCallExpression that represents calling itself as a constructed generic method. It then passes the MethodCallExpression to the Execute<TResult>(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 depends on the implementation of the type of the source parameter. The expected behavior is that the specified function, func, is applied to each value in the source sequence and the accumulated value is returned. The seed parameter is used as the seed value for the accumulated value, which corresponds to the first parameter in func. The final accumulated value is passed to selector to obtain the result value.
To simplify common aggregation operations, the set of standard query operators also includes two counting methods, Count and LongCount, and four numeric aggregation methods, namely Max, Min, Sum, and Average.
.NET FrameworkSupported in: 4.6, 4.5, 4, 3.5
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
Supported in: Windows Phone 8.1
Supported in: Windows Phone Silverlight 8.1
Supported in: Windows Phone Silverlight 8
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.