QueryableExtensions.FirstOrDefaultAsync QueryableExtensions.FirstOrDefaultAsync QueryableExtensions.FirstOrDefaultAsync Method

Definition

Overloads

FirstOrDefaultAsync<TSource>(IQueryable<TSource>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>)

Asynchronously returns the first element of a sequence, or a default value if the sequence contains no elements.

FirstOrDefaultAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

Asynchronously returns the first element of a sequence that satisfies a specified condition or a default value if no such element is found.

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

Asynchronously returns the first element of a sequence, or a default value if the sequence contains no elements.

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

Asynchronously returns the first element of a sequence that satisfies a specified condition or a default value if no such element is found.

FirstOrDefaultAsync<TSource>(IQueryable<TSource>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>)

Asynchronously returns the first element of a sequence, or a default value if the sequence contains no elements.

public static System.Threading.Tasks.Task<TSource> FirstOrDefaultAsync<TSource> (this System.Linq.IQueryable<TSource> source);
static member FirstOrDefaultAsync : System.Linq.IQueryable<'Source> -> System.Threading.Tasks.Task<'Source>
<Extension()>
Public Function FirstOrDefaultAsync(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

Task<TSource>

A task that represents the asynchronous operation. The task result contains default ( TSource ) if source is empty; otherwise, the first element in source.

Exceptions

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.

FirstOrDefaultAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) FirstOrDefaultAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

Asynchronously returns the first element of a sequence that satisfies a specified condition or a default value if no such element is found.

[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
public static System.Threading.Tasks.Task<TSource> FirstOrDefaultAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate);
static member FirstOrDefaultAsync : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> -> System.Threading.Tasks.Task<'Source>
<Extension()>
Public Function FirstOrDefaultAsync(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

Task<TSource>

A task that represents the asynchronous operation. The task result contains default ( TSource ) if source is empty or if no element passes the test specified by predicate ; otherwise, the first element in source that passes the test specified by predicate.

Exceptions

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.

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

Asynchronously returns the first element of a sequence, or a default value if the sequence contains no elements.

public static System.Threading.Tasks.Task<TSource> FirstOrDefaultAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Threading.CancellationToken cancellationToken);
static member FirstOrDefaultAsync : 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 CancellationToken CancellationToken

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

Returns

Task<TSource>

A task that represents the asynchronous operation. The task result contains default ( TSource ) if source is empty; otherwise, the first element in source.

Exceptions

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.

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

Asynchronously returns the first element of a sequence that satisfies a specified condition or a default value if no such element is found.

[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters")]
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
public static System.Threading.Tasks.Task<TSource> FirstOrDefaultAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate, System.Threading.CancellationToken cancellationToken);
static member FirstOrDefaultAsync : 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 CancellationToken CancellationToken

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

Returns

Task<TSource>

A task that represents the asynchronous operation. The task result contains default ( TSource ) if source is empty or if no element passes the test specified by predicate ; otherwise, the first element in source that passes the test specified by predicate.

Exceptions

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