QueryableExtensions.FirstAsync Method
Definition
Important
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Overloads
| FirstAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>, CancellationToken) |
Asynchronously returns the first element of a sequence that satisfies a specified condition. |
| FirstAsync<TSource>(IQueryable<TSource>, CancellationToken) |
Asynchronously returns the first element of a sequence. |
| FirstAsync<TSource>(IQueryable<TSource>) |
Asynchronously returns the first element of a sequence. |
| FirstAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) |
Asynchronously returns the first element of a sequence that satisfies a specified condition. |
FirstAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>, CancellationToken)
Asynchronously returns the first element of a sequence that satisfies a specified condition.
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters")]
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
public static System.Threading.Tasks.Task<TSource> FirstAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate, System.Threading.CancellationToken cancellationToken);static member FirstAsync : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'Source>Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IQueryable<TSource>
An IQueryable<T> to return the first element of.
- 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 first element in source that passes the test in
predicate.
- Attributes
Exceptions
source
or
predicate
is
null
.
No element satisfies the condition in
predicate
.
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
FirstAsync<TSource>(IQueryable<TSource>, CancellationToken)
Asynchronously returns the first element of a sequence.
public static System.Threading.Tasks.Task<TSource> FirstAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Threading.CancellationToken cancellationToken);static member FirstAsync : System.Linq.IQueryable<'Source> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'Source>Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IQueryable<TSource>
An IQueryable<T> to return the first element of.
- 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 first element in source.
Exceptions
source
is
null
.
The source sequence is empty.
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
FirstAsync<TSource>(IQueryable<TSource>)
Asynchronously returns the first element of a sequence.
public static System.Threading.Tasks.Task<TSource> FirstAsync<TSource> (this System.Linq.IQueryable<TSource> source);static member FirstAsync : System.Linq.IQueryable<'Source> -> System.Threading.Tasks.Task<'Source><Extension()>
Public Function FirstAsync(Of TSource) (source As IQueryable(Of TSource)) As Task(Of TSource)Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IQueryable<TSource>
An IQueryable<T> to return the first element of.
Returns
A task that represents the asynchronous operation.
The task result contains the first element in source.
Exceptions
source is null.
The source sequence is empty.
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
FirstAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)
Asynchronously returns the first element of a sequence that satisfies a specified condition.
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
public static System.Threading.Tasks.Task<TSource> FirstAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate);static member FirstAsync : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> -> System.Threading.Tasks.Task<'Source><Extension()>
Public Function FirstAsync(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Boolean))) As Task(Of TSource)Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IQueryable<TSource>
An IQueryable<T> to return the first element of.
- 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 first element in source that passes the test in
predicate.
- Attributes
Exceptions
source
or
predicate
is
null
.
No element satisfies the condition in
predicate
.
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