SaveChangesAsync(bool ensureAutoHistory = false, params IUnitOfWork[] unitOfWorks)这个怎么使用

[panda-big]

SaveChangesAsync(bool ensureAutoHistory = false, params IUnitOfWork[] unitOfWorks)
这个怎么使用？

我这边直接传IIUnitOfWork 报错：

TransactionScope必须在同一创建线程上

[rigofunc]

什么应用程序？web还是wpf？如果是web的话，默认每个就是Request Scope的呀

[panda-big]

是web，我有2个上下文对象是不同数据库的，例如：
private readonly IUnitOfWork<BusinessDbContext> _businessUnitOfWork; private readonly IUnitOfWork<SysManageDbContext> _sysmanageUnitOfWork; private readonly IConfiguration Configuration; public HomeService(IUnitOfWork<BusinessDbContext> businessUnitOfWork, IUnitOfWork<SysManageDbContext> sysmanageUnitOfWork, IConfiguration configuration) { _businessUnitOfWork = businessUnitOfWork; _sysmanageUnitOfWork = sysmanageUnitOfWork; Configuration = configuration; }
当我把 _businessUnitOfWork 和 _sysmanageUnitOfWork 放进数组进行保存的时候 就会报错。

[panda-big]

//add UnitOfWork
services.AddUnitOfWork<SysManageDbContext, BusinessDbContext>()

[rigofunc]

数据库是不同机器还是相同机器上的？

[panda-big]

是不同机器上的mysql数据库，我查了相关资料是因为使用了 await 的问题，需要如下使用：

using（var scope = new TransactionScope（TransactionScopeAsyncFlowOption.Enabled））
{
//todo
}

加上这个测试之后发现 还是报错，错误如下：
Microsoft.EntityFrameworkCore.Update[10000]
An exception occurred in the database while saving changes for context type 'Infrastructure.BusinessRepository.BusinessDbContext'.
System.InvalidOperationException: Error generated for warning 'Microsoft.EntityFrameworkCore.Database.Transaction.AmbientTransactionWarning: An ambient transaction has been detected. The current provider does not support ambient transactions. See http://go.microsoft.com/fwlink/?LinkId=800142'. This exception can be suppressed or logged by passing event ID 'RelationalEventId.AmbientTransactionWarning' to the 'ConfigureWarnings' method in 'DbContext.OnConfiguring' or 'AddDbContext'.
at Microsoft.EntityFrameworkCore.Diagnostics.EventDefinition.Log[TLoggerCategory](IDiagnosticsLogger1 logger, WarningBehavior warningBehavior, Exception exception) at Microsoft.EntityFrameworkCore.Internal.RelationalLoggerExtensions.AmbientTransactionWarning(IDiagnosticsLogger1 diagnostics, IRelationalConnection connection, DateTimeOffset startDate)
at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.HandleAmbientTransactions()
at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenAsync(CancellationToken cancellationToken, Boolean errorsExpected)
at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(DbContext _, ValueTuple2 parameters, CancellationToken cancellationToken) at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IReadOnlyList1 entriesToSave, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
System.InvalidOperationException: Error generated for warning 'Microsoft.EntityFrameworkCore.Database.Transaction.AmbientTransactionWarning: An ambient transaction has been detected. The current provider does not support ambient transactions. See http://go.microsoft.com/fwlink/?LinkId=800142'. This exception can be suppressed or logged by passing event ID 'RelationalEventId.AmbientTransactionWarning' to the 'ConfigureWarnings' method in 'DbContext.OnConfiguring' or 'AddDbContext'.
at Microsoft.EntityFrameworkCore.Diagnostics.EventDefinition.Log[TLoggerCategory](IDiagnosticsLogger1 logger, WarningBehavior warningBehavior, Exception exception) at Microsoft.EntityFrameworkCore.Internal.RelationalLoggerExtensions.AmbientTransactionWarning(IDiagnosticsLogger1 diagnostics, IRelationalConnection connection, DateTimeOffset startDate)
at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.HandleAmbientTransactions()
at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenAsync(CancellationToken cancellationToken, Boolean errorsExpected)
at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(DbContext _, ValueTuple2 parameters, CancellationToken cancellationToken) at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IReadOnlyList1 entriesToSave, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)

也就是说在.net core 里面已经不能使用TransactionScope 作为分布式事务的解决方案。
我也查看了相关资料说从.NET core 2.1 开始已经不再支持分布式事务因为移除了windows的 mstsc 远程。
所以这段代码的意义也就不存在了：
///

/// Saves all changes made in this context to the database with distributed transaction.
///

/// True if save changes ensure auto record the change history.
/// An optional array.
/// A that represents the asynchronous save operation. The task result contains the number of state entities written to database.
public async Task SaveChangesAsync(bool ensureAutoHistory = false, params IUnitOfWork[] unitOfWorks)
{
using (var ts = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled))
{
var count = 0;
foreach (var unitOfWork in unitOfWorks)
{
count += await unitOfWork.SaveChangesAsync(ensureAutoHistory);
}

            count += await SaveChangesAsync(ensureAutoHistory);

            ts.Complete();

            return count;
        }
    }

[panda-big]

目前框架就不支持分布式事务了

[rigofunc]

应该就是这个原因了，我已经几年没有写C#了，囧

[panda-big]

现在搞java了？

[panda-big]

我有个想法 想把查询表达式的条件封装类集成进来 达到可以根据自己组装条件的效果，例如：
//构造查询表达式
var PredicateBuilder = PredicateBuilder.Instance;
PredicateWrap expression = null;
if (!string.IsNullOrEmpty(roleRequestModel.StartTime))
{
expression &= PredicateBuilder.Equal(p => p.StartTime, Convert.ToDateTime(roleRequestModel.StartTime));
}
if (!string.IsNullOrEmpty(roleRequestModel.EndTime))
{
expression &= PredicateBuilder.Equal(p => p.EndTime, Convert.ToDateTime(roleRequestModel.EndTime));
}
list = await repository.GetPagedListAsync(
predicate: expression,
orderBy: a => a.OrderByDescending(b => b.CreateTime),
pageIndex: roleRequestModel.PageCurrent,
pageSize: roleRequestModel.PageSize);

[rigofunc]

你可以提交一个PR，我看一下

[panda-big]

后续 我抽时间去弄，因为 我已经在我的项目里面用了，提交了我在告诉你。

[tanher]

所以这个问题不解决了吗？现在代码还是没变，但 .net core 已经到 5.0 了，现在还在报错： A TransactionScope must be disposed on the same thread that it was created.

[panda-big]

这个分布式事务，在core里面已经不能使用了。我是下载的源代码去掉了。