QueryableExtensions.CountAsync Method
Definition
Important
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Overloads
| CountAsync<TSource>(IQueryable<TSource>) |
Asynchronously returns the number of elements in a sequence. |
| CountAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) |
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. |
| 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>)
Asynchronously returns the number of elements in a sequence.
public static System.Threading.Tasks.Task<int> CountAsync<TSource> (this System.Linq.IQueryable<TSource> source);static member CountAsync : System.Linq.IQueryable<'Source> -> System.Threading.Tasks.Task<int><Extension()>
Public Function CountAsync(Of TSource) (source As IQueryable(Of TSource)) 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.
Returns
A task that represents the asynchronous operation. The task result contains the number of elements in the input sequence.
Exceptions
source
is
null
.
source
doesn't implement
IDbAsyncQueryProvider
.
The number of elements in
source
is larger than
MaxValue
.
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.
Applies to
CountAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)
Asynchronously returns the number of elements in a sequence that satisfy a condition.
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
public static System.Threading.Tasks.Task<int> CountAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate);static member CountAsync : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> -> System.Threading.Tasks.Task<int><Extension()>
Public Function CountAsync(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Boolean))) 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.
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.
- Attributes
Exceptions
source
or
predicate
is
null
.
source
doesn't implement
IDbAsyncQueryProvider
.
The number of elements in
source
that satisfy the condition in the predicate function
is larger than
MaxValue
.
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.
Applies to
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);static member CountAsync : System.Linq.IQueryable<'Source> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<int>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
.
source
doesn't implement
IDbAsyncQueryProvider
.
The number of elements in
source
is larger than
MaxValue
.
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.
Applies to
CountAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>, CancellationToken)
Asynchronously returns the number of elements in a sequence that satisfy a condition.
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters")]
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);static member CountAsync : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<int>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.
- Attributes
Exceptions
source
or
predicate
is
null
.
source
doesn't implement
IDbAsyncQueryProvider
.
The number of elements in
source
that satisfy the condition in the predicate function
is larger than
MaxValue
.
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.
Applies to
Entity Framework