EntityFrameworkQueryableExtensions.CountAsync Method
Definition
Important
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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
A task that represents the asynchronous operation. The task result contains the number of elements in the input sequence.
Exceptions
source is null.
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.
Applies to
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
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
source or predicate is null.
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.
