Queryable.Sum Method (IQueryable<Nullable<Double>>)
Computes the sum of a sequence of nullable Double values.
Assemblies: System.Linq.Queryable (in System.Linq.Queryable.dll)
System.Core (in System.Core.dll)
public static Nullable<double> Sum( this IQueryable<Nullable<double>> source )
Usage NoteIn Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<Nullable<Double>>. 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).
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 it returns the sum of the values in source.
The following code example demonstrates how to use Sum(IQueryable<Nullable<Single>>) to sum the values of a sequence.
This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. To extend the example to this topic, substitute the elements of the source sequence with elements of the appropriate numerical type.