# Queryable.Sum Method

## Definition

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Computes the sum of a sequence of numeric values.

## Overloads

Sum(IQueryable<Decimal>) |
Computes the sum of a sequence of Decimal values. |

Sum(IQueryable<Double>) |
Computes the sum of a sequence of Double values. |

Sum(IQueryable<Int32>) |
Computes the sum of a sequence of Int32 values. |

Sum(IQueryable<Int64>) |
Computes the sum of a sequence of Int64 values. |

Sum(IQueryable<Nullable<Decimal>>) |
Computes the sum of a sequence of nullable Decimal values. |

Sum(IQueryable<Nullable<Double>>) |
Computes the sum of a sequence of nullable Double values. |

Sum(IQueryable<Nullable<Int32>>) |
Computes the sum of a sequence of nullable Int32 values. |

Sum(IQueryable<Nullable<Int64>>) |
Computes the sum of a sequence of nullable Int64 values. |

Sum(IQueryable<Nullable<Single>>) |
Computes the sum of a sequence of nullable Single values. |

Sum(IQueryable<Single>) |
Computes the sum of a sequence of Single values. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) |
Computes the sum of the sequence of nullable Int32 values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) |
Computes the sum of the sequence of Single values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) |
Computes the sum of the sequence of nullable Single values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) |
Computes the sum of the sequence of nullable Int64 values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) |
Computes the sum of the sequence of nullable Double values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) |
Computes the sum of the sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) |
Computes the sum of the sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) |
Computes the sum of the sequence of Double values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) |
Computes the sum of the sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence. |

Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) |
Computes the sum of the sequence of nullable Decimal values that is obtained by invoking a projection function on each element of the input sequence. |

## Sum(IQueryable<Decimal>)

Computes the sum of a sequence of Decimal values.

```
public:
[System::Runtime::CompilerServices::Extension]
static System::Decimal Sum(System::Linq::IQueryable<System::Decimal> ^ source);
```

`public static decimal Sum (this System.Linq.IQueryable<decimal> source);`

`static member Sum : System.Linq.IQueryable<decimal> -> decimal`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Decimal)) As Decimal
```

#### Parameters

- source
- IQueryable<Decimal>

A sequence of Decimal values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

The sum is larger than MaxValue.

### Remarks

The Sum(IQueryable<Decimal>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Decimal>) 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<Decimal>) 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`

.

### Applies to

## Sum(IQueryable<Double>)

Computes the sum of a sequence of Double values.

```
public:
[System::Runtime::CompilerServices::Extension]
static double Sum(System::Linq::IQueryable<double> ^ source);
```

`public static double Sum (this System.Linq.IQueryable<double> source);`

`static member Sum : System.Linq.IQueryable<double> -> double`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Double)) As Double
```

#### Parameters

- source
- IQueryable<Double>

A sequence of Double values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

### Remarks

The Sum(IQueryable<Double>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Double>) 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<Double>) 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`

.

### Applies to

## Sum(IQueryable<Int32>)

Computes the sum of a sequence of Int32 values.

```
public:
[System::Runtime::CompilerServices::Extension]
static int Sum(System::Linq::IQueryable<int> ^ source);
```

`public static int Sum (this System.Linq.IQueryable<int> source);`

`static member Sum : System.Linq.IQueryable<int> -> int`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Integer)) As Integer
```

#### Parameters

- source
- IQueryable<Int32>

A sequence of Int32 values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

The sum is larger than MaxValue.

### Remarks

The Sum(IQueryable<Int32>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Int32>) 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<Int32>) 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`

.

### Applies to

## Sum(IQueryable<Int64>)

Computes the sum of a sequence of Int64 values.

```
public:
[System::Runtime::CompilerServices::Extension]
static long Sum(System::Linq::IQueryable<long> ^ source);
```

`public static long Sum (this System.Linq.IQueryable<long> source);`

`static member Sum : System.Linq.IQueryable<int64> -> int64`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Long)) As Long
```

#### Parameters

- source
- IQueryable<Int64>

A sequence of Int64 values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

The sum is larger than MaxValue.

### Remarks

The Sum(IQueryable<Int64>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Int64>) 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<Int64>) 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`

.

### Applies to

## Sum(IQueryable<Nullable<Decimal>>)

Computes the sum of a sequence of nullable Decimal values.

```
public:
[System::Runtime::CompilerServices::Extension]
static Nullable<System::Decimal> Sum(System::Linq::IQueryable<Nullable<System::Decimal>> ^ source);
```

`public static decimal? Sum (this System.Linq.IQueryable<decimal?> source);`

`static member Sum : System.Linq.IQueryable<Nullable<decimal>> -> Nullable<decimal>`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Nullable(Of Decimal))) As Nullable(Of Decimal)
```

#### Parameters

- source
- IQueryable<Nullable<Decimal>>

A sequence of nullable Decimal values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

The sum is larger than MaxValue.

### Remarks

The Sum(IQueryable<Nullable<Decimal>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Decimal>>) 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<Decimal>>) 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`

.

### Applies to

## Sum(IQueryable<Nullable<Double>>)

Computes the sum of a sequence of nullable Double values.

```
public:
[System::Runtime::CompilerServices::Extension]
static Nullable<double> Sum(System::Linq::IQueryable<Nullable<double>> ^ source);
```

`public static double? Sum (this System.Linq.IQueryable<double?> source);`

`static member Sum : System.Linq.IQueryable<Nullable<double>> -> Nullable<double>`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Nullable(Of Double))) As Nullable(Of Double)
```

#### Parameters

- source
- IQueryable<Nullable<Double>>

A sequence of nullable Double values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

### Remarks

The Sum(IQueryable<Nullable<Double>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Double>>) 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<Double>>) 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`

.

### Applies to

## Sum(IQueryable<Nullable<Int32>>)

Computes the sum of a sequence of nullable Int32 values.

```
public:
[System::Runtime::CompilerServices::Extension]
static Nullable<int> Sum(System::Linq::IQueryable<Nullable<int>> ^ source);
```

`public static int? Sum (this System.Linq.IQueryable<int?> source);`

`static member Sum : System.Linq.IQueryable<Nullable<int>> -> Nullable<int>`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Nullable(Of Integer))) As Nullable(Of Integer)
```

#### Parameters

- source
- IQueryable<Nullable<Int32>>

A sequence of nullable Int32 values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

The sum is larger than MaxValue.

### Remarks

The Sum(IQueryable<Nullable<Int32>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Int32>>) 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<Int32>>) 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`

.

### Applies to

## Sum(IQueryable<Nullable<Int64>>)

Computes the sum of a sequence of nullable Int64 values.

```
public:
[System::Runtime::CompilerServices::Extension]
static Nullable<long> Sum(System::Linq::IQueryable<Nullable<long>> ^ source);
```

`public static long? Sum (this System.Linq.IQueryable<long?> source);`

`static member Sum : System.Linq.IQueryable<Nullable<int64>> -> Nullable<int64>`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Nullable(Of Long))) As Nullable(Of Long)
```

#### Parameters

- source
- IQueryable<Nullable<Int64>>

A sequence of nullable Int64 values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

The sum is larger than MaxValue.

### Remarks

The Sum(IQueryable<Nullable<Int64>>) method generates a MethodCallExpression that represents calling Sum(IQueryable<Nullable<Int64>>) 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<Int64>>) 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`

.

### Applies to

## Sum(IQueryable<Nullable<Single>>)

Computes the sum of a sequence of nullable Single values.

```
public:
[System::Runtime::CompilerServices::Extension]
static Nullable<float> Sum(System::Linq::IQueryable<Nullable<float>> ^ source);
```

`public static float? Sum (this System.Linq.IQueryable<float?> source);`

`static member Sum : System.Linq.IQueryable<Nullable<single>> -> Nullable<single>`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Nullable(Of Single))) As Nullable(Of Single)
```

#### Parameters

- source
- IQueryable<Nullable<Single>>

A sequence of nullable Single values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

### Examples

The following code example demonstrates how to use Sum(IQueryable<Nullable<Single>>) to sum the values of a sequence.

```
float?[] points = { null, 0, 92.83F, null, 100.0F, 37.46F, 81.1F };
float? sum = points.AsQueryable().Sum();
Console.WriteLine("Total points earned: {0}", sum);
/*
This code produces the following output:
Total points earned: 311.39
*/
```

```
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()
MsgBox("Total points earned: " & sum)
'This code produces the following output:
'Total points earned: 311.39
```

### 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`

.

### Applies to

## Sum(IQueryable<Single>)

Computes the sum of a sequence of Single values.

```
public:
[System::Runtime::CompilerServices::Extension]
static float Sum(System::Linq::IQueryable<float> ^ source);
```

`public static float Sum (this System.Linq.IQueryable<float> source);`

`static member Sum : System.Linq.IQueryable<single> -> single`

```
<Extension()>
Public Function Sum (source As IQueryable(Of Single)) As Single
```

#### Parameters

- source
- IQueryable<Single>

A sequence of Single values to calculate the sum of.

#### Returns

The sum of the values in the sequence.

#### Exceptions

`source`

is `null`

.

### Examples

The following code example demonstrates how to use Sum(IQueryable<Single>) to sum the values of a sequence.

```
List<float> numbers = new List<float> { 43.68F, 1.25F, 583.7F, 6.5F };
float sum = numbers.AsQueryable().Sum();
Console.WriteLine("The sum of the numbers is {0}.", sum);
/*
This code produces the following output:
The sum of the numbers is 635.13.
*/
```

```
Dim numbers As New List(Of Single)(New Single() {43.68F, 1.25F, 583.7F, 6.5F})
Dim sum As Single = numbers.AsQueryable().Sum()
MsgBox("The sum of the numbers is " & sum)
' This code produces the following output:
' The sum of the numbers is 635.13.
```

### Remarks

The Sum(IQueryable<Single>) method generates a MethodCallExpression that represents calling Sum(IQueryable<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<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`

.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>)

Computes the sum of the sequence of nullable Int32 values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<int> Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, Nullable<int>> ^> ^ selector);
```

`public static int? Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,int?>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, Nullable<int>>> -> Nullable<int>`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Nullable(Of Integer)))) As Nullable(Of Integer)
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Nullable<Int32>>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

The sum is larger than MaxValue.

### Examples

The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

Note

This code example uses an overload of the method that's different from the specific overload that this article describes. To extend the example to the overload that this article describes, change the body of the `selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

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 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int32>>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>)

Computes the sum of the sequence of Single values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static float Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, float> ^> ^ selector);
```

`public static float Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,float>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, single>> -> single`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Single))) As Single
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Single>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

### Examples

The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

Note

This code example uses an overload of the method that's different from the specific overload that this article describes. To extend the example to the overload that this article describes, change the body of the `selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

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 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Single>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>)

Computes the sum of the sequence of nullable Single values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<float> Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, Nullable<float>> ^> ^ selector);
```

`public static float? Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,float?>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, Nullable<single>>> -> Nullable<single>`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Nullable(Of Single)))) As Nullable(Of Single)
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Nullable<Single>>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

### Examples

The following code example demonstrates how to use Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) to sum the projected values of a sequence.

Note

This code example uses an overload of the method that's different from the specific overload that this article describes. To extend the example to the overload that this article describes, change the body of the `selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

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 Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Single>>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>)

Computes the sum of the sequence of nullable Int64 values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<long> Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, Nullable<long>> ^> ^ selector);
```

`public static long? Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,long?>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, Nullable<int64>>> -> Nullable<int64>`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Nullable(Of Long)))) As Nullable(Of Long)
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Nullable<Int64>>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

The sum is larger than MaxValue.

### Examples

Note

`selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Int64>>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>)

Computes the sum of the sequence of nullable Double values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<double> Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, Nullable<double>> ^> ^ selector);
```

`public static double? Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,double?>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, Nullable<double>>> -> Nullable<double>`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Nullable(Of Double)))) As Nullable(Of Double)
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Nullable<Double>>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

### Examples

Note

`selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Double>>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>)

Computes the sum of the sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static long Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, long> ^> ^ selector);
```

`public static long Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,long>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, int64>> -> int64`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Long))) As Long
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Int64>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

The sum is larger than MaxValue.

### Examples

Note

`selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int64>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>)

Computes the sum of the sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static int Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, int> ^> ^ selector);
```

`public static int Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,int>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, int>> -> int`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Integer))) As Integer
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Int32>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

The sum is larger than MaxValue.

### Examples

Note

`selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>)

Computes the sum of the sequence of Double values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static double Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, double> ^> ^ selector);
```

`public static double Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,double>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, double>> -> double`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Double))) As Double
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Double>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

### Examples

Note

`selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Double>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>)

Computes the sum of the sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static System::Decimal Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, System::Decimal> ^> ^ selector);
```

`public static decimal Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,decimal>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, decimal>> -> decimal`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Decimal))) As Decimal
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Decimal>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

The sum is larger than MaxValue.

### Examples

Note

`selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Decimal>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.

### Applies to

## Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>)

Computes the sum of the sequence of nullable Decimal values that is obtained by invoking a projection function on each element of the input sequence.

```
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static Nullable<System::Decimal> Sum(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, Nullable<System::Decimal>> ^> ^ selector);
```

`public static decimal? Sum<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,decimal?>> selector);`

`static member Sum : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, Nullable<decimal>>> -> Nullable<decimal>`

```
<Extension()>
Public Function Sum(Of TSource) (source As IQueryable(Of TSource), selector As Expression(Of Func(Of TSource, Nullable(Of Decimal)))) As Nullable(Of Decimal)
```

#### Type Parameters

- TSource

The type of the elements of `source`

.

#### Parameters

- source
- IQueryable<TSource>

A sequence of values of type `TSource`

.

- selector
- Expression<Func<TSource,Nullable<Decimal>>>

A projection function to apply to each element.

#### Returns

The sum of the projected values.

#### Exceptions

`source`

or `selector`

is `null`

.

The sum is larger than MaxValue.

### Examples

Note

`selector`

function.

```
class Package
{
public string Company { get; set; }
public double Weight { get; set; }
}
public static void SumEx3()
{
List<Package> packages =
new List<Package>
{ new Package { Company = "Coho Vineyard", Weight = 25.2 },
new Package { Company = "Lucerne Publishing", Weight = 18.7 },
new Package { Company = "Wingtip Toys", Weight = 6.0 },
new Package { Company = "Adventure Works", Weight = 33.8 } };
// Calculate the sum of all package weights.
double totalWeight = packages.AsQueryable().Sum(pkg => pkg.Weight);
Console.WriteLine("The total weight of the packages is: {0}", totalWeight);
}
/*
This code produces the following output:
The total weight of the packages is: 83.7
*/
```

```
Structure Package
Public Company As String
Public Weight As Double
End Structure
Shared Sub SumEx3()
Dim packages As New List(Of Package)(New Package() { _
New Package With {.Company = "Coho Vineyard", .Weight = 25.2}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0}, _
New Package With {.Company = "Adventure Works", .Weight = 33.8}})
' Calculate the sum of all package weights.
Dim totalWeight As Double = packages.AsQueryable().Sum(Function(pkg) pkg.Weight)
MsgBox("The total weight of the packages is: " & totalWeight)
End Sub
'This code produces the following output:
'The total weight of the packages is: 83.7
```

### Remarks

The Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) method generates a MethodCallExpression that represents calling Sum<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) 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<TSource>(IQueryable<TSource>, Expression<Func<TSource,Nullable<Decimal>>>) depends on the implementation of the type of the `source`

parameter. The expected behavior is that it invokes `selector`

on each element of `source`

and returns the sum of the resulting values.