EntityFrameworkQueryableExtensions.CountAsync Method

Definition

Namespace:

Microsoft.EntityFrameworkCore

Assembly:

Microsoft.EntityFrameworkCore.dll

Package:

Microsoft.EntityFrameworkCore v8.0.0

Overloads

CountAsync<TSource>(IQueryable<TSource>, CancellationToken)	Asynchronously returns the number of elements in a sequence.
CountAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>, CancellationToken)	Asynchronously returns the number of elements in a sequence that satisfy a condition.

CountAsync<TSource>(IQueryable<TSource>, CancellationToken)

Asynchronously returns the number of elements in a sequence.

public static System.Threading.Tasks.Task<int> CountAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Threading.CancellationToken cancellationToken = default);

static member CountAsync : System.Linq.IQueryable<'Source> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<int>

<Extension()>
Public Function CountAsync(Of TSource) (source As IQueryable(Of TSource), Optional cancellationToken As CancellationToken = Nothing) As Task(Of Integer)

Type Parameters

TSource

The type of the elements of source.

Parameters

source

IQueryable<TSource>

An IQueryable<T> that contains the elements to be counted.

cancellationToken

CancellationToken

A CancellationToken to observe while waiting for the task to complete.

Returns

Task<Int32>

A task that represents the asynchronous operation. The task result contains the number of elements in the input sequence.

Exceptions

ArgumentNullException

source is null.

OperationCanceledException

If the CancellationToken is canceled.

Remarks

Multiple active operations on the same context instance are not supported. Use await to ensure that any asynchronous operations have completed before calling another method on this context. See Avoiding DbContext threading issues for more information and examples.

See Querying data with EF Core for more information and examples.

CountAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>, CancellationToken)

Asynchronously returns the number of elements in a sequence that satisfy a condition.

public static System.Threading.Tasks.Task<int> CountAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate, System.Threading.CancellationToken cancellationToken = default);

static member CountAsync : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<int>

<Extension()>
Public Function CountAsync(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Boolean)), Optional cancellationToken As CancellationToken = Nothing) As Task(Of Integer)

Type Parameters

TSource

The type of the elements of source.

Parameters

source

IQueryable<TSource>

An IQueryable<T> that contains the elements to be counted.

predicate

Expression<Func<TSource,Boolean>>

A function to test each element for a condition.

cancellationToken

CancellationToken

A CancellationToken to observe while waiting for the task to complete.

Returns

Task<Int32>

A task that represents the asynchronous operation. The task result contains the number of elements in the sequence that satisfy the condition in the predicate function.

Exceptions

ArgumentNullException

source or predicate is null.

OperationCanceledException

If the CancellationToken is canceled.

Remarks

Multiple active operations on the same context instance are not supported. Use await to ensure that any asynchronous operations have completed before calling another method on this context. See Avoiding DbContext threading issues for more information and examples.

See Querying data with EF Core for more information and examples.