Using a TransactionScope with async/await

Maybe you didn’t know but the System.Transactions.TransactionScope object in .NET doesn’t play nice together with the async/await syntax. As long as all the code inside the TransactionScope is executed on the same thread, there is no issue. But when you start combining it with async/await you get into trouble. The following code doesn’t work in .NET 4.5:

	public async Task WrapInsideATransaction() {
	using (var tx = new TransactionScope())
	{
	await SomeAsyncMethod();
	tx.Complete();
	}
	}
	private async Task SomeAsyncMethod()
	{
	await Task.Delay(1000);
	}

view raw TransactionScopeWithAsyncAwait.cs hosted with ❤ by GitHub

Whenyou try to execute this code, it will fail with the following error:

System.InvalidOperationException : A TransactionScope must be disposed on the same thread that it was created.

A fix is available in .NET 4.5.1 but requires some code changes. There is a new enumeration TransactionScopeAsyncFlowOption that can be provided in the TransactionScope constructor. Here is the fixed code:

	public async Task WrapInsideATransaction() {
	using (var tx = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled))
	{
	await SomeAsyncMethod();
	tx.Complete();
	}
	}
	private async Task SomeAsyncMethod()
	{
	await Task.Delay(1000);
	}

view raw TransactionScopeWithAsyncAwaitFixed.cs hosted with ❤ by GitHub