CODEWITHSUNDEEP
c#linqforeach
Richa
Richa

Reputation: 3289

Using LINQ in Parallel.Foreach

I have following normal foreach using LINQ query, How can i transform it using Parallel.Foreach

foreach (var i in media.Where(x => x is Video)
{
    this.Update(i);
}

How can i do it like

Parallel.ForEach(media,i =>
{
    //LINQ
});

Upvotes: 4

Views: 12939

Answers (5)

Blindy
Blindy

Reputation: 67564

The first argument to Parallel.ForEach is an enumerable, so the obvious way would be:

Parallel.ForEach(media.Where(x => x is Video).OrderBy(x => x.Contains("a")), i =>
{
    //this.Update(i);
    // commented out because you'll probably want to Invoke it
    // depending on what it does exactly.

});

Upvotes: 10

Frank
Frank

Reputation: 4481

You can do either

Parallel.ForEach(media.Where(x => x is Video), this.Update);

or

media.AsParallel().Where(x => x is Video).ForAll(this.Update);

Adding an order in a parallel process makes no sense here.

Upvotes: 3

Denis Itskovich
Denis Itskovich

Reputation: 4543

First of all, Where(x => x is Video) can be replaced by OfType<Video>().
Second, for fluent syntax it's better to use ParallelEnumerable.ForAll extension method:

media.OfType<Video>()
    .AsParallel()
    .ForAll(this.Update)

Upvotes: 12

Amol Bavannavar
Amol Bavannavar

Reputation: 2072

Try this :

Parallel.ForEach<Video>(media.Where(x => x is Video), i =>
{
    this.Update(i);
};

Upvotes: 1

Noctis
Noctis

Reputation: 11783

Well ... basically like you've said ... but ... keep in mind that if you need to order the results and you're acting on that, it's not really parallel ...

The linq parallel foreach will partition your collection and work on it at the same time, which you also need to take into account making sure your this.Update can work with multiple users without messing up .

So, what's the question really ?

Upvotes: 0

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