一、DbContext.Database.BeginTransactionAsync() 模式
1. 注意事项：连接字符串中启用了 MARS（Multiple Active Result Sets：MultipleActiveResultSets=True ）后，无法创建 保存点（保存点与 SQL Server 的多重活动结果集不兼容），此时，使用注入的 DbContext（例如：@inject ApplicationDbContext FirstDb） 将报错。解决办法：在 事务 中自己 new 一个 DbContext。
"ConnectionStrings": {"Ky1SqlServerConnection": "Server=localhost;Database=kyglxt;Trusted_Connection=True;MultipleActiveResultSets=True;TrustServerCertificate=True;User=sa;Password=123456","Ky2SQLiteConnection": "Data Source=SQLiteFile.db",}上述语句为 appsettings.json 中保存的 连接字符串。
/* SQL Server 事务测试 —— ok
* 注：Multiple Active Result Sets(MARS) is enabled：MultipleActiveResultSets = True; 时，不能使用注入的 DbContext，在 事务 中自己 new 一个 DbContext。*/
try
{using (var FirstDb = new KyglxtContext(new DbContextOptionsBuilder<KyglxtContext>().UseSqlServer(AppsettingsJsonService.Configuration["ConnectionStrings:Ky1SqlServerConnection"]).Options)){var transaction = await FirstDb.Database.BeginTransactionAsync();var FirstDbEntity01 = new 用户表 { 用户名 = $"Entity in FirstDb：{DateTime.Now}" };FirstDb.Add(FirstDbEntity01);await FirstDb.SaveChangesAsync();System.Console.WriteLine("————save 1，end");await Task.Delay(2000);System.Console.WriteLine("————delay end");var FirstDbEntity02 = new 用户表 { 名称 = $"Entity in FirstDb：{DateTime.Now}" };FirstDb.Add(FirstDbEntity02);await FirstDb.SaveChangesAsync();System.Console.WriteLine("————save 2，end");// Commit transaction if all commands succeed, transaction will auto-rollback when disposed if either commands failsawait transaction.CommitAsync();System.Console.WriteLine("————try，ok");}
}
catch (Exception ex)
{System.Console.WriteLine(ex.Message);System.Console.WriteLine(ex.InnerException?.Message);
}
finally { }2. 对于 环境事务（TransactionScope） ，SQLite 不支持，针对多个数据库使用 事务 功能时，不能包含 SQLite。解决办法1：生产环境，SQLite 换成 SQL Server 。解决办法2：手动处理。
/* 手动处理 多个数据库，支持 SQLite */try{using var FirstDb = new KyglxtContext(new DbContextOptionsBuilder<KyglxtContext>().UseSqlServer(AppsettingsJsonService.Configuration["ConnectionStrings:Ky1SqlServerConnection"]).Options);using var SecondDb = new ApplicationDbContext(new DbContextOptionsBuilder<ApplicationDbContext>().UseSqlite(AppsettingsJsonService.Configuration["ConnectionStrings:Ky2SQLiteConnection"]).Options);var FirstTransaction = await FirstDb.Database.BeginTransactionAsync();var SecondTransaction = await SecondDb.Database.BeginTransactionAsync();try{var firstEntity = new 用户表 { 用户名 = $"BeginTransactionAsync，2：{DateTime.Now}" };FirstDb.Add(firstEntity);await FirstDb.SaveChangesAsync();System.Console.WriteLine("FirstDb————save 1，end");await Task.Delay(2000);System.Console.WriteLine("BeginTransactionAsync，2————————delay end");var secondEntity = new ApplicationUser { UserName = $"BeginTransactionAsync，2：{DateTime.Now}" };SecondDb.Add(secondEntity);await SecondDb.SaveChangesAsync();System.Console.WriteLine("SecondDb————save 2，end");await FirstTransaction.CommitAsync();await SecondTransaction.CommitAsync();System.Console.WriteLine("BeginTransactionAsync，2——————try，ok");}catch (Exception ex){await FirstTransaction.RollbackAsync();await SecondTransaction.RollbackAsync();System.Console.WriteLine($"BeginTransactionAsync，2——————catch，{ex.Message}");System.Console.WriteLine($"BeginTransactionAsync，2——————catch，{ex.InnerException?.Message}");}}catch (Exception ex){System.Console.WriteLine($"BeginTransactionAsync，2——————catch，{ex.Message}");System.Console.WriteLine($"BeginTransactionAsync，2——————catch，{ex.InnerException?.Message}");}finally{System.Console.WriteLine("BeginTransactionAsync，2——————finally：");}二、环境事务，System.Transactions、TransactionScope：支持操作多个数据库
/* 环境事务：支持操作多个数据库，但是 SQLite 不支持 TransactionScope */try{using (var scope = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled)){using (var FirstDb = new KyglxtContext(new DbContextOptionsBuilder<KyglxtContext>().UseSqlServer(AppsettingsJsonService.Configuration["ConnectionStrings:Ky1SqlServerConnection"]).Options)){var firstEntity = new 用户表 { 用户名 = $"TransactionScope：{DateTime.Now}" };FirstDb.Add(firstEntity);await FirstDb.SaveChangesAsync();System.Console.WriteLine("FirstDb————save 1，end");await Task.Delay(2000);System.Console.WriteLine("TransactionScope————————delay end");using (var SecondDb = new ApplicationDbContext(new DbContextOptionsBuilder<ApplicationDbContext>().UseSqlite(AppsettingsJsonService.Configuration["ConnectionStrings:Ky2SQLiteConnection"]).Options)){var secondEntity = new ApplicationUser { UserName = $"TransactionScope：{DateTime.Now}" };SecondDb.Add(secondEntity);await SecondDb.SaveChangesAsync();}System.Console.WriteLine("SecondDb————save 2，end");}// Commit transaction if all commands succeed, transaction will auto-rollback when disposed if either commands failsscope.Complete();System.Console.WriteLine("TransactionScope——————try，ok");}}catch (Exception ex){// Handle the exception (e.g., log it)System.Console.WriteLine($"TransactionScope——————catch，{ex.Message}");System.Console.WriteLine($"TransactionScope——————catch，{ex.InnerException?.Message}");}finally{System.Console.WriteLine("TransactionScope——————finally：");}
