Overview
Parallel programming is very important to know and C# does it so well. This post is all about the System.Threading namespace. More information can be found here.
Example
How do we make a line of code execute in the background on a separate thread?
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class Program {
public static void Main(string[] args) {
// Start task with the constructor
var t1 = new Task( () => DoWork(1, 1000) );
t1.Start();
// Start task with a factory
var t2 = Task.Factory.StartNew( () => DoWork(2, 1200) )
.ContinueWith( (prevTask) => DoOtherWork(2, 1200) );
}
public static void DoWork(int id, int sleepTime) {
Console.WriteLine("Task {0} starting.", id);
Thread.sleep(sleepTime);
Console.WriteLine("Task {0} stopping.", id);
}
public static void DoOtherWork(int id, int sleepTime) {
Console.WriteLine("Other Task {0} starting.", id);
Thread.sleep(sleepTime);
Console.WriteLine("Other Task {0} stopping.", id);
}
}
/*
Task 2 starting.
Task 1 starting.
Task 1 stopping.
Task 2 stopping.
Other Task 2 starting.
Other Task 2 stopping.
*/
Given the code above, how do we wait on the main thread until all the tasks are done?
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public static void Main(string[] args) {
var t1 = Task.Factory.StartNew( () => DoWork(1, 1000) );
var t2 = Task.Factory.StartNew( () => DoWork(2, 1200) );
var taskList = new List<Task>{t1, t2};
// or we could use Task.WaitAny
Task.WaitAll( taskList.ToArray() );
Console.WriteLine("Finished all tasks");
}