Convert a foreach loop to Parallel.Foreach loop

It is not hard to turn a serial foreach loop to a parallel foreach loop.

The serial loop built with entity framework looks like this:


NORTHWNDEntities ctx = new NORTHWNDEntities();


var result = from r in ctx.Products select r;


foreach (Product product in result)


  Console.WriteLine(“Serial: Product ID: {0}, Product Name: {1}”, product.ProductID, product.ProductName);


To turn it to Parallel you do it like below:


Parallel.ForEach(result, product =>


  Console.WriteLine(“Parallel: Product ID: {0}, Product Name: {1}”, product.ProductID, product.ProductName);



But not all the conversion will make your code run faster. It will not be running faster if the code depends on a lot in IO. You might need to look into Interlocked or you might use the alternative such as Parallel.Invoke.

About chanmingman

Since March 2011 Microsoft Live Spaces migrated to Wordpress ( till now, I have is over 1 million viewers. This blog is about more than 50% telling you how to resolve error messages, especial for Microsoft products. The blog also has a lot of guidance teaching you how to get stated certain Microsoft technologies. The blog also uses as a help to keep my memory. The blog is never meant to give people consulting services or silver bullet solutions. It is a contribution to the community. Thanks for your support over the years. Ming Man is Microsoft MVP since year 2006. He is a software development manager for a multinational company. With 25 years of experience in the IT field, he has developed system using Clipper, COBOL, VB5, VB6, VB.NET, Java and C #. He has been using Visual Studio (.NET) since the Beta back in year 2000. He and the team have developed many projects using .NET platform such as SCM, and HR based applications. He is familiar with the N-Tier design of business application and is also an expert with database experience in MS SQL, Oracle and AS 400.
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