C# 确保2个数据库的完整性

所以，我有两个数据库。。。用户数据库和另一个也包含用户表的数据库。两者都有一个电子邮件字段。我想同时更新两个电子邮件字段

（简化）代码如下所示：

using(var db1 = new Db1Context())
using(var db2 = new Db2Context())
{
    db1.Users.Single(u => u.Email == oldEmail).Email = someEmail;
    db2.Users.Single(u => u.Email == oldEmail).Email = someEmail;
    db1.SaveChanges();
    db2.SaveChanges(); //what if this fails?
}

因此，尝试1：

using(var db1 = new Db1Context())
using(var db2 = new Db2Context())
using(var txs = new TransactionScope())
{
    db1.Users.Single(u => u.Email == oldEmail).Email = someEmail;
    db2.Users.Single(u => u.Email == oldEmail).Email = someEmail;
    db1.SaveChanges();
    db2.SaveChanges(); //what if this fails?
    txs.Complete();
}

失败，出现

ArgumentException

和以下堆栈跟踪：

[ArgumentException: Value does not fall within the expected range.]
   System.Transactions.Oletx.IDtcProxyShimFactory.ConnectToProxy(String nodeName, Guid resourceManagerIdentifier, IntPtr managedIdentifier, Boolean& nodeNameMatches, UInt32& whereaboutsSize, CoTaskMemHandle& whereaboutsBuffer, IResourceManagerShim& resourceManagerShim) +0
   System.Transactions.Oletx.DtcTransactionManager.Initialize() +155
   System.Transactions.Oletx.DtcTransactionManager.get_ProxyShimFactory() +76
   System.Transactions.TransactionInterop.GetOletxTransactionFromTransmitterPropigationToken(Byte[] propagationToken) +160
   System.Transactions.TransactionStatePSPEOperation.PSPEPromote(InternalTransaction tx) +78
...[etc...]

据我们所知，这是因为

因此，现在我们尝试使用SqlTransactions：

using(var db1 = new Db1Context())
using(var db2 = new Db2Context())
{
    if(db1.Database.Connection.State == ConnectionState.Closed)
    {
        //transaction can only work on open connection
        db1.Database.Connection.Open(); 
    }
    using(var tx = db1.Database.Connection.BeginTransaction())
    {
        //ArgumentException on next line
        db1.Users.Single(u => u.Email == oldEmail).Email = someEmail;
        db2.Users.Single(u => u.Email == oldEmail).Email = someEmail;
        db1.SaveChanges();
        db2.SaveChanges(); //what if this fails?
    }
}

此操作失败并出现错误：

ArgumentException:“EntityConnection只能使用闭合的DbConnection构造。”

---

那么我们如何才能做到这一点呢？

简单地说，你不能。您需要实现2PC来支持这一点。听起来Azure有一些非常严重的限制