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EntityFrameworkQueryableExtensions.cs
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EntityFrameworkQueryableExtensions.cs
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// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using JetBrains.Annotations;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.EntityFrameworkCore.Extensions.Internal;
using Microsoft.EntityFrameworkCore.Internal;
using Microsoft.EntityFrameworkCore.Query;
using Microsoft.EntityFrameworkCore.Query.Internal;
using Microsoft.EntityFrameworkCore.Utilities;
// ReSharper disable once CheckNamespace
namespace Microsoft.EntityFrameworkCore
{
/// <summary>
/// Entity Framework LINQ related extension methods.
/// </summary>
public static class EntityFrameworkQueryableExtensions
{
#region Any/All
private static readonly MethodInfo _any = GetMethod(nameof(Queryable.Any));
/// <summary>
/// Asynchronously determines whether a sequence contains any elements.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to check for being empty.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains <c>true</c> if the source sequence contains any elements; otherwise, <c>false</c>.
/// </returns>
public static Task<bool> AnyAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, bool>(_any, source, cancellationToken);
}
private static readonly MethodInfo _anyPredicate = GetMethod(nameof(Queryable.Any), 1);
/// <summary>
/// Asynchronously determines whether any element of a sequence satisfies a condition.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> whose elements to test for a condition.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains <c>true</c> if any elements in the source sequence pass the test in the specified
/// predicate; otherwise, <c>false</c>.
/// </returns>
public static Task<bool> AnyAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, bool>(_anyPredicate, source, predicate, cancellationToken);
}
private static readonly MethodInfo _allPredicate = GetMethod(nameof(Queryable.All), 1);
/// <summary>
/// Asynchronously determines whether all the elements of a sequence satisfy a condition.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> whose elements to test for a condition.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains <c>true</c> if every element of the source sequence passes the test in the specified
/// predicate; otherwise, <c>false</c>.
/// </returns>
public static Task<bool> AllAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, bool>(_allPredicate, source, predicate, cancellationToken);
}
#endregion
#region Count/LongCount
private static readonly MethodInfo _count = GetMethod(nameof(Queryable.Count));
/// <summary>
/// Asynchronously returns the number of elements in a sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to be counted.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the number of elements in the input sequence.
/// </returns>
public static Task<int> CountAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, int>(_count, source, cancellationToken);
}
private static readonly MethodInfo _countPredicate = GetMethod(nameof(Queryable.Count), 1);
/// <summary>
/// Asynchronously returns the number of elements in a sequence that satisfy a condition.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to be counted.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <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.
/// </returns>
public static Task<int> CountAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, int>(_countPredicate, source, predicate, cancellationToken);
}
private static readonly MethodInfo _longCount = GetMethod(nameof(Queryable.LongCount));
/// <summary>
/// Asynchronously returns an <see cref="Int64" /> that represents the total number of elements in a sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to be counted.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the number of elements in the input sequence.
/// </returns>
public static Task<long> LongCountAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, long>(_longCount, source, cancellationToken);
}
private static readonly MethodInfo _longCountPredicate = GetMethod(nameof(Queryable.LongCount), 1);
/// <summary>
/// Asynchronously returns an <see cref="Int64" /> that represents the number of elements in a sequence
/// that satisfy a condition.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to be counted.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <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.
/// </returns>
public static Task<long> LongCountAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, long>(_longCountPredicate, source, predicate, cancellationToken);
}
#endregion
#region First/FirstOrDefault
private static readonly MethodInfo _first = GetMethod(nameof(Queryable.First));
/// <summary>
/// Asynchronously returns the first element of a sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the first element of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the first element in <paramref name="source" />.
/// </returns>
public static Task<TSource> FirstAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_first, source, cancellationToken);
}
private static readonly MethodInfo _firstPredicate = GetMethod(nameof(Queryable.First), 1);
/// <summary>
/// Asynchronously returns the first element of a sequence that satisfies a specified condition.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the first element of.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the first element in <paramref name="source" /> that passes the test in
/// <paramref name="predicate" />.
/// </returns>
public static Task<TSource> FirstAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, TSource>(_firstPredicate, source, predicate, cancellationToken);
}
private static readonly MethodInfo _firstOrDefault = GetMethod(nameof(Queryable.FirstOrDefault));
/// <summary>
/// Asynchronously returns the first element of a sequence, or a default value if the sequence contains no elements.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the first element of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains <c>default</c> ( <typeparamref name="TSource" /> ) if
/// <paramref name="source" /> is empty; otherwise, the first element in <paramref name="source" />.
/// </returns>
public static Task<TSource> FirstOrDefaultAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_firstOrDefault, source, cancellationToken);
}
private static readonly MethodInfo _firstOrDefaultPredicate = GetMethod(nameof(Queryable.FirstOrDefault), 1);
/// <summary>
/// Asynchronously returns the first element of a sequence that satisfies a specified condition
/// or a default value if no such element is found.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the first element of.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains <c>default</c> ( <typeparamref name="TSource" /> ) if <paramref name="source" />
/// is empty or if no element passes the test specified by <paramref name="predicate" /> ; otherwise, the first
/// element in <paramref name="source" /> that passes the test specified by <paramref name="predicate" />.
/// </returns>
public static Task<TSource> FirstOrDefaultAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, TSource>(_firstOrDefaultPredicate, source, predicate, cancellationToken);
}
#endregion
#region Last/LastOrDefault
private static readonly MethodInfo _last = GetMethod(nameof(Queryable.Last));
/// <summary>
/// Asynchronously returns the last element of a sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the last element of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the last element in <paramref name="source" />.
/// </returns>
public static Task<TSource> LastAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_last, source, cancellationToken);
}
private static readonly MethodInfo _lastPredicate = GetMethod(nameof(Queryable.Last), 1);
/// <summary>
/// Asynchronously returns the last element of a sequence that satisfies a specified condition.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the last element of.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the last element in <paramref name="source" /> that passes the test in
/// <paramref name="predicate" />.
/// </returns>
public static Task<TSource> LastAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, TSource>(_lastPredicate, source, predicate, cancellationToken);
}
private static readonly MethodInfo _lastOrDefault = GetMethod(nameof(Queryable.LastOrDefault));
/// <summary>
/// Asynchronously returns the last element of a sequence, or a default value if the sequence contains no elements.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the last element of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains <c>default</c> ( <typeparamref name="TSource" /> ) if
/// <paramref name="source" /> is empty; otherwise, the last element in <paramref name="source" />.
/// </returns>
public static Task<TSource> LastOrDefaultAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_lastOrDefault, source, cancellationToken);
}
private static readonly MethodInfo _lastOrDefaultPredicate = GetMethod(nameof(Queryable.LastOrDefault), 1);
/// <summary>
/// Asynchronously returns the last element of a sequence that satisfies a specified condition
/// or a default value if no such element is found.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the last element of.
/// </param>
/// <param name="predicate"> A function to test each element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains <c>default</c> ( <typeparamref name="TSource" /> ) if <paramref name="source" />
/// is empty or if no element passes the test specified by <paramref name="predicate" /> ; otherwise, the last
/// element in <paramref name="source" /> that passes the test specified by <paramref name="predicate" />.
/// </returns>
public static Task<TSource> LastOrDefaultAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, TSource>(_lastOrDefaultPredicate, source, predicate, cancellationToken);
}
#endregion
#region Single/SingleOrDefault
private static readonly MethodInfo _single = GetMethod(nameof(Queryable.Single));
/// <summary>
/// Asynchronously returns the only element of a sequence, and throws an exception
/// if there is not exactly one element in the sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the single element of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the single element of the input sequence.
/// </returns>
public static Task<TSource> SingleAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_single, source, cancellationToken);
}
private static readonly MethodInfo _singlePredicate = GetMethod(nameof(Queryable.Single), 1);
/// <summary>
/// Asynchronously returns the only element of a sequence that satisfies a specified condition,
/// and throws an exception if more than one such element exists.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the single element of.
/// </param>
/// <param name="predicate"> A function to test an element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the single element of the input sequence that satisfies the condition in
/// <paramref name="predicate" />.
/// </returns>
public static Task<TSource> SingleAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, TSource>(_singlePredicate, source, predicate, cancellationToken);
}
private static readonly MethodInfo _singleOrDefault = GetMethod(nameof(Queryable.SingleOrDefault));
/// <summary>
/// Asynchronously returns the only element of a sequence, or a default value if the sequence is empty;
/// this method throws an exception if there is more than one element in the sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the single element of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the single element of the input sequence, or <c>default</c> (
/// <typeparamref name="TSource" />)
/// if the sequence contains no elements.
/// </returns>
public static Task<TSource> SingleOrDefaultAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_singleOrDefault, source, cancellationToken);
}
private static readonly MethodInfo _singleOrDefaultPredicate = GetMethod(nameof(Queryable.SingleOrDefault), 1);
/// <summary>
/// Asynchronously returns the only element of a sequence that satisfies a specified condition or
/// a default value if no such element exists; this method throws an exception if more than one element
/// satisfies the condition.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> to return the single element of.
/// </param>
/// <param name="predicate"> A function to test an element for a condition. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the single element of the input sequence that satisfies the condition in
/// <paramref name="predicate" />, or <c>default</c> ( <typeparamref name="TSource" /> ) if no such element is found.
/// </returns>
public static Task<TSource> SingleOrDefaultAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, bool>> predicate,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(predicate, nameof(predicate));
return ExecuteAsync<TSource, TSource>(_singleOrDefaultPredicate, source, predicate, cancellationToken);
}
#endregion
#region Min
private static readonly MethodInfo _min = GetMethod(nameof(Queryable.Min), predicate: mi => mi.IsGenericMethod);
/// <summary>
/// Asynchronously returns the minimum value of a sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to determine the minimum of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the minimum value in the sequence.
/// </returns>
public static Task<TSource> MinAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_min, source, cancellationToken);
}
private static readonly MethodInfo _minSelector = GetMethod(nameof(Queryable.Min), 1, mi => mi.IsGenericMethod);
/// <summary>
/// Asynchronously invokes a projection function on each element of a sequence and returns the minimum resulting value.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <typeparam name="TResult">
/// The type of the value returned by the function represented by <paramref name="selector" /> .
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to determine the minimum of.
/// </param>
/// <param name="selector"> A projection function to apply to each element. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the minimum value in the sequence.
/// </returns>
public static Task<TResult> MinAsync<TSource, TResult>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, TResult>> selector,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(selector, nameof(selector));
return ExecuteAsync<TSource, TResult>(_minSelector, source, selector, cancellationToken);
}
#endregion
#region Max
private static readonly MethodInfo _max = GetMethod(nameof(Queryable.Max), predicate: mi => mi.IsGenericMethod);
/// <summary>
/// Asynchronously returns the maximum value of a sequence.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to determine the maximum of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the maximum value in the sequence.
/// </returns>
public static Task<TSource> MaxAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<TSource, TSource>(_max, source, cancellationToken);
}
private static readonly MethodInfo _maxSelector = GetMethod(nameof(Queryable.Max), 1, mi => mi.IsGenericMethod);
/// <summary>
/// Asynchronously invokes a projection function on each element of a sequence and returns the maximum resulting value.
/// </summary>
/// <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.
/// </remarks>
/// <typeparam name="TSource">
/// The type of the elements of <paramref name="source" />.
/// </typeparam>
/// <typeparam name="TResult">
/// The type of the value returned by the function represented by <paramref name="selector" /> .
/// </typeparam>
/// <param name="source">
/// An <see cref="IQueryable{T}" /> that contains the elements to determine the maximum of.
/// </param>
/// <param name="selector"> A projection function to apply to each element. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the maximum value in the sequence.
/// </returns>
public static Task<TResult> MaxAsync<TSource, TResult>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, TResult>> selector,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(selector, nameof(selector));
return ExecuteAsync<TSource, TResult>(_maxSelector, source, selector, cancellationToken);
}
#endregion
#region Sum
private static readonly MethodInfo _sumDecimal = GetMethod<decimal>(nameof(Queryable.Sum));
/// <summary>
/// Asynchronously computes the sum of a sequence of values.
/// </summary>
/// <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.
/// </remarks>
/// <param name="source">
/// A sequence of values to calculate the sum of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the sum of the values in the sequence.
/// </returns>
public static Task<decimal> SumAsync(
[NotNull] this IQueryable<decimal> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<decimal, decimal>(_sumDecimal, source, cancellationToken);
}
private static readonly MethodInfo _sumNullableDecimal = GetMethod<decimal?>(nameof(Queryable.Sum));
/// <summary>
/// Asynchronously computes the sum of a sequence of values.
/// </summary>
/// <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.
/// </remarks>
/// <param name="source">
/// A sequence of values to calculate the sum of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the sum of the values in the sequence.
/// </returns>
public static Task<decimal?> SumAsync(
[NotNull] this IQueryable<decimal?> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<decimal?, decimal?>(_sumNullableDecimal, source, cancellationToken);
}
private static readonly MethodInfo _sumDecimalSelector = GetMethod<decimal>(nameof(Queryable.Sum), 1);
/// <summary>
/// Asynchronously computes the sum of the sequence of values that is obtained by invoking a projection function on
/// each element of the input sequence.
/// </summary>
/// <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.
/// </remarks>
/// <param name="source">
/// A sequence of values of type <typeparamref name="TSource" />.
/// </param>
/// <param name="selector"> A projection function to apply to each element. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the sum of the projected values..
/// </returns>
public static Task<decimal> SumAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, decimal>> selector,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(selector, nameof(selector));
return ExecuteAsync<TSource, decimal>(_sumDecimalSelector, source, selector, cancellationToken);
}
private static readonly MethodInfo _sumNullableDecimalSelector = GetMethod<decimal?>(nameof(Queryable.Sum), 1);
/// <summary>
/// Asynchronously computes the sum of the sequence of values that is obtained by invoking a projection function on
/// each element of the input sequence.
/// </summary>
/// <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.
/// </remarks>
/// <param name="source">
/// A sequence of values of type <typeparamref name="TSource" />.
/// </param>
/// <param name="selector"> A projection function to apply to each element. </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the sum of the projected values..
/// </returns>
public static Task<decimal?> SumAsync<TSource>(
[NotNull] this IQueryable<TSource> source,
[NotNull] Expression<Func<TSource, decimal?>> selector,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
Check.NotNull(selector, nameof(selector));
return ExecuteAsync<TSource, decimal?>(_sumNullableDecimalSelector, source, selector, cancellationToken);
}
private static readonly MethodInfo _sumInt = GetMethod<int>(nameof(Queryable.Sum));
/// <summary>
/// Asynchronously computes the sum of a sequence of values.
/// </summary>
/// <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.
/// </remarks>
/// <param name="source">
/// A sequence of values to calculate the sum of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>
/// A task that represents the asynchronous operation.
/// The task result contains the sum of the values in the sequence.
/// </returns>
public static Task<int> SumAsync(
[NotNull] this IQueryable<int> source,
CancellationToken cancellationToken = default(CancellationToken))
{
Check.NotNull(source, nameof(source));
return ExecuteAsync<int, int>(_sumInt, source, cancellationToken);
}
private static readonly MethodInfo _sumNullableInt = GetMethod<int?>(nameof(Queryable.Sum));
/// <summary>
/// Asynchronously computes the sum of a sequence of values.
/// </summary>
/// <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.
/// </remarks>
/// <param name="source">
/// A sequence of values to calculate the sum of.
/// </param>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken" /> to observe while waiting for the task to complete.
/// </param>
/// <returns>