Added DbExtensions for database transactions

AMWD.Common.EntityFrameworkCore/Extensions/DbContextExensions.cs

@@ -0,0 +1,91 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore.Storage;
+
+namespace Microsoft.EntityFrameworkCore
+{
+	/// <summary>
+	/// Extensions for the <see cref="DbContext"/>.
+	/// </summary>
+	public static class DbContextExensions
+	{
+		/// <summary>
+		/// Starts a new transaction.
+		/// </summary>
+		/// <remarks>
+		/// See <see href="https://aka.ms/efcore-docs-transactions">Transactions in EF Core</see> for more information.
+		/// </remarks>
+		/// <param name="dbContext">The current <see cref="DbContext"/>.</param>
+		/// <returns>
+		/// A <see cref="IDbContextTransaction" /> that represents the started transaction.
+		/// </returns>
+		public static IDbContextTransaction BeginTransaction(this DbContext dbContext)
+		{
+			if (dbContext.Database.GetProviderType() == DatabaseFacadeExtensions.DatabaseProvider.InMemory)
+				return new DbContextTransactionStub();
+
+			return dbContext.Database.BeginTransaction();
+		}
+
+		/// <summary>
+		/// Asynchronously starts a new transaction.
+		/// </summary>
+		/// <remarks>
+		/// <para>
+		/// Entity Framework Core does not support multiple parallel operations being run on the same DbContext instance. This
+		/// includes both parallel execution of async queries and any explicit concurrent use from multiple threads.
+		/// Therefore, always await async calls immediately, or use separate DbContext instances for operations that execute
+		/// in parallel. See <see href="https://aka.ms/efcore-docs-threading">Avoiding DbContext threading issues</see>
+		/// for more information.
+		/// </para>
+		/// <para>
+		/// See <see href="https://aka.ms/efcore-docs-transactions">Transactions in EF Core</see> for more information.
+		/// </para>
+		/// </remarks>
+		/// <param name="dbContext">The current <see cref="DbContext"/>.</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 transaction initialization. The task result contains a <see cref="IDbContextTransaction" /> that represents the started transaction.
+		/// </returns>
+		/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken" /> is canceled.</exception>
+		public static Task<IDbContextTransaction> BeginTransactionAsync(this DbContext dbContext, CancellationToken cancellationToken)
+		{
+			if (dbContext.Database.GetProviderType() == DatabaseFacadeExtensions.DatabaseProvider.InMemory)
+				return Task.FromResult<IDbContextTransaction>(new DbContextTransactionStub());
+
+			return dbContext.Database.BeginTransactionAsync(cancellationToken);
+		}
+
+		/// <inheritdoc cref="IDbContextTransaction" />
+		private class DbContextTransactionStub : IDbContextTransaction
+		{
+			/// <inheritdoc />
+			public Guid TransactionId { get; private set; } = Guid.NewGuid();
+
+			/// <inheritdoc />
+			public void Commit()
+			{ }
+
+			/// <inheritdoc />
+			public Task CommitAsync(CancellationToken cancellationToken = default)
+				=> Task.CompletedTask;
+
+			/// <inheritdoc />
+			public void Dispose()
+			{ }
+
+			/// <inheritdoc />
+			public ValueTask DisposeAsync()
+				=> new(Task.CompletedTask);
+
+			/// <inheritdoc />
+			public void Rollback()
+			{ }
+
+			/// <inheritdoc />
+			public Task RollbackAsync(CancellationToken cancellationToken = default)
+				=> Task.CompletedTask;
+		}
+	}
+}