.NET 4中并行编程的简单例子

namespaceForEachDemo
{
usingSystem;
usingSystem.Drawing;//requiressystem.Drawing.dll
usingSystem.IO;
usingSystem.Threading;
usingSystem.Threading.Tasks;

classSimpleForEach
{
staticvoidMain()
{
//Asimplesourcefordemonstrationpurposes.Modifythispathasnecessary.
string[]files=System.IO.Directory.GetFiles(@"C:\Users\Public\Pictures\SamplePictures","*.jpg");
stringnewDir=@"C:\Users\Public\Pictures\SamplePictures\Modified";
System.IO.Directory.CreateDirectory(newDir);

//Methodsignature:Parallel.ForEach(IEnumerable<TSource>source,Action<TSource>body)
Parallel.ForEach(files,currentFile=>
{
//Themorecomputationalworkyoudohere,thegreater
//thespeedupcomparedtoasequentialforeachloop.
stringfilename=System.IO.Path.GetFileName(currentFile);
System.Drawing.Bitmapbitmap=newSystem.Drawing.Bitmap(currentFile);

bitmap.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);
bitmap.Save(System.IO.Path.Combine(newDir,filename));

//Peekbehindthescenestoseehowworkisparallelized.
//Butbeaware:ThreadcontentionfortheConsoleslowsdownparallelloops!!!
Console.WriteLine("Processing{0}onthread{1}",filename,
Thread.CurrentThread.ManagedThreadId);

}//closelambdaexpression
);//closemethodinvocation

//Keeptheconsolewindowopenindebugmode.
Console.WriteLine("Processingcomplete.Pressanykeytoexit.");
Console.ReadKey();
}
}
}

注意：

并行编程与之前的多线程的区别，并行编程其实可以理解为多核编程，它可以更好地利用多CPU的优势。而之前的多线程其实是需要切换线程的。