TransactionScopeAsyncFlowOption and Isolation Level?

Question

I'm using Entity Framework 6.1 in a WCF service and wanted to surround my SELECT query with a READ UNCOMMITTED Isolation level since other batch updates will be inserted into the table I'm reading and don't want to lock those batch updates from occurring when a READ is performed on the table. This basically simulates a SELECT WITH NOLOCK.

This code was also being used in an asynchronous fashion. Hence, I could not simply use TransacactionScope. Note that I'm also using the .Net 4.5.1 framework.

I could set the Isolation Level on TransactionScope to ReadUncommitted, but TransactionScopeOption has the default of ReadCommitted. I don't see any way to change the Isolation Level.

Is there any way to change the Isolation Level? If I can't set the Isolation Level, would my query be okay to run under the above circumstances.

Actually, if I can't set the Isolation level to "NOLOCK", there is no need for me to even include the TransactionScopeAsyncFlowOption.

"I could set the Isolation Level on TransactionScope to ReadUncommitted, but TransactionScopeOption has the default of ReadCommitted. I don't see any way to change the Isolation Level." That is a contradiction. You say you can set the level but somehow you can't. Why? — usr, May 02 '14 at 14:12
I can only set the isolation level using TransactionScope, but NOT TransactionScopeAsyncFlowOption I meant to say... — sagesky36, May 02 '14 at 14:14
There appears to be no isolation settings for it. You can read about if you search on TransactionScopeAsyncFlowOption. — sagesky36, May 02 '14 at 14:29
What about using this ctor? http://msdn.microsoft.com/en-us/library/dn249390(v=vs.110).aspx I'm trying to understand the problem here because the solution seems too simple. — usr, May 02 '14 at 14:44

score 15 · Answer 1 · answered Apr 08 '16 at 22:40

Use the constructor option with the TransactionScopeAsyncFlowOption specified as the third parameter, not the the first:

using (var scope = new TransactionScope(
    TransactionScopeOption.Required,  
    new TransactionOptions { IsolationLevel = IsolationLevel.ReadUncommitted },
    TransactionScopeAsyncFlowOption.Enabled)) 
{
}

TransactionScopeAsyncFlowOption and Isolation Level?

1 Answers1