Queryable.Sum Method (IQueryable<Nullable<Single>>)
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Computes the sum of a sequence of nullable Single values.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function Sum ( _
source As IQueryable(Of Nullable(Of Single)) _
) As Nullable(Of Single)
public static Nullable<float> Sum(
this IQueryable<Nullable<float>> source
)
Parameters
- source
Type: System.Linq.IQueryable<Nullable<Single>>
A sequence of nullable Single values to calculate the sum of.
Return Value
Type: System.Nullable<Single>
The sum of the values in the sequence.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<Nullable<Single>>. When you use instance method syntax to call this method, omit the first parameter.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | source is nulla null reference (Nothing in Visual Basic). |
Remarks
The Sum(IQueryable<Nullable<Single>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Single>>) 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 Sum(IQueryable<Nullable<Single>>) 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.
Examples
The following code example demonstrates how to use Sum(IQueryable<Nullable<Single>>) to sum the values of a sequence.
Dim points As Nullable(Of Single)() = {Nothing, 0, 92.83F, Nothing, 100.0F, 37.46F, 81.1F}
Dim sum As Nullable(Of Single) = points.AsQueryable().Sum()
outputBlock.Text &= "Total points earned: " & sum & vbCrLf
'This code produces the following output:
'Total points earned: 311.39
float?[] points = { null, 0, 92.83F, null, 100.0F, 37.46F, 81.1F };
float? sum = points.AsQueryable().Sum();
outputBlock.Text += String.Format("Total points earned: {0}", sum) + "\n";
/*
This code produces the following output:
Total points earned: 311.39
*/
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.