EF Core Nested Transaction

纪录一下目前解法( EF Core 3.1 适用，其他版本尚未试过 )

   public class NestedTransactionManager : IDbContextTransactionManager{    readonly ISqlServerConnection _sqlServerConnection;    public NestedTransactionManager(ISqlServerConnection sqlServerConnection)    {        // Dependency inject ISqlServerConnection, ISqlServerConnection is original IDbContextTransactionManager in EF Core 3.1 .        _sqlServerConnection = sqlServerConnection;    }    int Layer = 0;    public IDbContextTransaction CurrentTransaction        => _sqlServerConnection.CurrentTransaction;    public IDbContextTransaction BeginTransaction()    {        if (Layer++ == 0)            _sqlServerConnection.BeginTransaction();        return new NestedTransation(this, Layer);    }    public async Task<IDbContextTransaction> BeginTransactionAsync(CancellationToken cancellationToken = default)    {        if (Layer++ == 0)            await _sqlServerConnection.BeginTransactionAsync(cancellationToken);        return new NestedTransation(this, Layer);    }    public void CommitTransaction()    {        if (Layer-- <= 1)            _sqlServerConnection.CommitTransaction();    }    public Task CommitTransactionAsync(CancellationToken cancellationToken = default)        => Layer-- <= 1        ? _sqlServerConnection.CurrentTransaction.CommitAsync(cancellationToken)        : Task.CompletedTask;            public void ResetState()        => _sqlServerConnection.ResetState();    public Task ResetStateAsync(CancellationToken cancellationToken = default)        => _sqlServerConnection.ResetStateAsync(cancellationToken);    public void RollbackTransaction()        => _sqlServerConnection.RollbackTransaction();}

class NestedTransation : IDbContextTransaction{    readonly NestedTransactionManager _manager;    readonly int _layer;    public NestedTransation(NestedTransactionManager manager, int layer)    {        _manager = manager;        _layer = layer;    }    bool Commited => _layer > _manager.Layer;    public Guid TransactionId        => Transaction.TransactionId;    IDbContextTransaction Transaction        => _manager.CurrentTransaction;    public void Commit()        => _manager.CommitTransaction();    public Task CommitAsync(CancellationToken cancellationToken = default)        => _manager.CommitTransactionAsync(cancellationToken);    public void Dispose()    {        if (!Commited && Transaction != null)            Transaction.Dispose();    }    public ValueTask DisposeAsync()        => !Commited && Transaction != null        ? Transaction.DisposeAsync()        : default;    public void Rollback()        => Transaction.Rollback();    public Task RollbackAsync(CancellationToken cancellationToken = default)        => Transaction.RollbackAsync(cancellationToken);}

services.AddDbContext<AppDbContext>(options =>{    ...    options.ReplaceService<IDbContextTransactionManager, NestedTransactionManager>();});