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如何知道代码是否在TransactionScope中?

transactionscope .net c#

26

nightcoder · 技术社区 · 15 年前

了解代码块是否在TransactionScope中的最佳方法是什么?
当前交易是一种可实现的方式还是有任何微妙之处?
是否可以通过反射访问内部ContextData.CurrentData.CurrentScope(在System.Transactions中)?如果是,怎么办?

2 回复 | 直到 15 年前

1

39

Thomas Levesque 15 年前

Transaction.Current 应该是可靠的;我刚刚检查过,在这一点上,抑制交易也可以:

Console.WriteLine(Transaction.Current != null); // false
using (TransactionScope tran = new TransactionScope())
{
    Console.WriteLine(Transaction.Current != null); // true
    using (TransactionScope tran2 = new TransactionScope(
          TransactionScopeOption.Suppress))
    {
        Console.WriteLine(Transaction.Current != null); // false
    }
    Console.WriteLine(Transaction.Current != null); // true
}
Console.WriteLine(Transaction.Current != null); // false

2

4

nightcoder 15 年前

这里有更可靠的方法(如我前面所说的,transaction.current可以手动设置,并不意味着我们真的处于transactionscope中)。也可以通过反射获得这些信息,但发射IL的速度比反射快100倍。

private Func<TransactionScope> _getCurrentScopeDelegate;

bool IsInsideTransactionScope
{
  get
  {
    if (_getCurrentScopeDelegate == null)
    {
      _getCurrentScopeDelegate = CreateGetCurrentScopeDelegate();
    }

    TransactionScope ts = _getCurrentScopeDelegate();
    return ts != null;
  }
}

private Func<TransactionScope> CreateGetCurrentScopeDelegate()
{
  DynamicMethod getCurrentScopeDM = new DynamicMethod(
    "GetCurrentScope",
    typeof(TransactionScope),
    null,
    this.GetType(),
    true);

  Type t = typeof(Transaction).Assembly.GetType("System.Transactions.ContextData");
  MethodInfo getCurrentContextDataMI = t.GetProperty(
    "CurrentData", 
    BindingFlags.NonPublic | BindingFlags.Static)
    .GetGetMethod(true);

  FieldInfo currentScopeFI = t.GetField("CurrentScope", BindingFlags.NonPublic | BindingFlags.Instance);

  ILGenerator gen = getCurrentScopeDM.GetILGenerator();
  gen.Emit(OpCodes.Call, getCurrentContextDataMI);
  gen.Emit(OpCodes.Ldfld, currentScopeFI);
  gen.Emit(OpCodes.Ret);

  return (Func<TransactionScope>)getCurrentScopeDM.CreateDelegate(typeof(Func<TransactionScope>));
}

[Test]
public void IsInsideTransactionScopeTest()
{
  Assert.IsFalse(IsInsideTransactionScope);
  using (new TransactionScope())
  {
    Assert.IsTrue(IsInsideTransactionScope);
  }
  Assert.IsFalse(IsInsideTransactionScope);
}