For example, while reading a large file, it's better to let the user do some other work. Hence, what's the difference between multithreading and multitasking or are they the same? Multitasking Multitasking refers to allowing the user to perform multiple tasks at the same time. The user can listen to music running in the background, while writing a blog. Hence, the computer is performing multiple tasks for the user. Each task requires resources. Since the computer has limited resources, the number of tasks performed at the same time are also limited.
Multithreading Multithreading is used to perform multiple tasks. Each task can have multiple threads. In a multithreaded application, the user can do more in a short span of time than a single thread application. Today, almost every application uses multiple threading. An application or a process can have a user interface thread that manages interactions with the user and background worker threads that perform other tasks. Once all foreground threads have been stopped, the runtime stops all background threads and shuts down.
You can change a thread to execute in the background by setting the IsBackground property at any time. Background threads are useful for any operation that should continue as long as an application is running but should not prevent the application from terminating, such as monitoring file system changes or incoming socket connections. Sleep method can be used to pause the current thread for a fixed period of time in milliseconds. The following code snippet pauses a thread for 1 second.
It is often required that some data needs to be passed to a worker thread from the main thread. Start method has an overloaded form that takes an object type parameter. The ParemeterizedThreadStart delegate is used when you need to pass to the thread. We want to execute these methods in two separate worker threads.
As you can clearly see, both methods take a parameter of object type. The following code snippet starts a new worker thread that executes the PrintJob method.
In this case, I pass a string as a parameter. The PrintPerson method of the Print class takes a complex object of type Person. In the following code snippet, I create a Person class and pass it as a parameter of the Thread. Start method. The ParameterizedThreadStart delegate supports only a single parameter. To pass complex or multiple data items, you can pass an Array, a collection type, or a tuple type. Threads can also be blocked or go into sleep or other unresolved states.
This is where thread pool comes in handy. A thread pool is a pool of worker threads that have already been created and are available for apps to use them as needed. Once thread pool threads finish executing their tasks, they go back to the pool. NET provides a managed thread pool via the ThreadPool class that is managed by the system. For any short background tasks, the managed thread pool is a better choice than creating and managing your own threads. Thread pool threads are good for background process only and not recommended for foreground threads.
There is only one thread pool per process. The ThreadPool class has several static methods, including the QueueUserWorkItem, that is responsible for calling a thread pool worker thread when it is available.
If no worker thread is available in the thread pool, it waits until the thread becomes available. You'll also need to set the local directory to which you want to download. This is pretty straight forward. You'll also want to add some files to the list that need to be downloaded. Note : The example code in this article is for a C WPF application, and will be slightly different for a C forms application. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services. Privacy policy. You can write multithreaded applications in Microsoft Visual C.
NET or in Visual C. I tried to fix it with threads, like this:. But the RunFileDownload ; function starts before the files are downloaded.
I try solve this with "Thread. Join ;" but again not displayed messages The main thread is paused. I thought solve it with a multi-thread and Thread. Join ; but it isn't efficient and i will have problems with others functions in the main thread. How can i expect the thread finish before the rest of the code is executed? I try with Thread. Join ; but it freezes the application. Note that exceptions with await are, suffice it to say, less than kind.
Consider using this pattern: Fire-and-forget with async vs "old async delegate" and reading this article. Note that StartDownloads needs to be async and return a Task for this to work.
0コメント