async-await

问题 I'm writing a Python program to interact with a device based on a CAN Bus. I'm using the python-can module successfully for this purpose. I'm also using asyncio to react to asynchronous events. I have written a "CanBusManager" class that is used by the "CanBusSequencer" class. The "CanBusManager" class takes care of generating/sending/receiving messages, and the CanBusSequencer drives the sequence of messages to be sent. At some point in the sequence I want to wait until a specific message is

问题 I'm tring to make a database query inside a LINQ statement asynchronous, but I'm running into an error. The code below runs fine with out async/await var newEntities = _repositoryMapping.Mapper.Map<List<Entry>>(entries); newEntities = newEntities.Where(async e => await !_context.Entries.AnyAsync(c => c.Id == e.Id)).ToList(); Severity Code Description Project File Line Suppression State Error CS4010 Cannot convert async lambda expression to delegate type 'Func<Entry, bool>'. An async lambda

问题 I do not understand how is the control returned to the caller when using async- await, since when i execute this code, the first thread gets practically destroyed when calling task inside the awaited method, and the thread that gives the result executes all remaining code.Below i have also drawn a diagram of how i thought the execution is, but it seems it is wrong. Assumed workflow according to "returning control to the caller": Results Main public static string GetThreadId => Thread

问题 I'm having a hard time understanding how async/await works.I have to make a program which contains three functions: func1 func2 and concatenated . func1 takes a string as an argument and returns the same string after 5 seconds of delay, func2 is an async function which also takes a string as an argument and returns the same string. concatenated is a function that takes two strings (s1,s2) as arguments and uses the above two functions( (func1(s1) and func2(s2)) ) to return their concatenated

问题 I'm having a hard time understanding how async/await works.I have to make a program which contains three functions: func1 func2 and concatenated . func1 takes a string as an argument and returns the same string after 5 seconds of delay, func2 is an async function which also takes a string as an argument and returns the same string. concatenated is a function that takes two strings (s1,s2) as arguments and uses the above two functions( (func1(s1) and func2(s2)) ) to return their concatenated

问题 I have read a few SO questions that touches in this question, even though many of them are several years old: How do you write a Service handler in ServiceStack API so that it becomes async/await? There are no docs on docs.servicestack.net that mentions async/await at all, I just find some community forum posts. I think that the only thing you need to do, to change this non-async method: public GetBookingResponse Get(GetBooking getBooking) { Booking booking = _objectGetter.GetBooking

问题 I have been researching about async/await vs await Task.Run but have not found a definite conclusion. Does "async/await" always run on a separate thread from the UI? And if yes why use "await Task.Run"? From my research, the recommendation is to use "await Task.Run" for CPU intensive tasks and "await/async" for data transfer scenarios (I/O) but others have recommended using await Task.Run (if needing the return) or just Task.Run (fire and forget) for ANY longer running activities in Xamarin.

问题 I have written a recursive Promise in javascript which seems to be working fine but I wanted to test it using setTimeout() to be sure that I'm awaiting correctly before continuing with the execution. Here is the gist of my code: try{ await renameFiles(); // <-- await here console.log("do other stuff"); } catch(){ } const renameFiles = (path) => { return new Promise(resolve => { console.log("Renaming files..."); fs.readdirSync(path).forEach(file) => { // if file is a directory ... let newPath

问题 I am new in Protractor. And I am doing tests to be familiar with it. Here, I met a problem what I cannot distinguish between ignoreSynchronization and async/await method. I had 3 blocks to test them. The first is clear with protractor's own async features. it('without await and ignoreSynchronization', async function() { await browser.waitForAngularEnabled(false); await browser.driver.get('https://www.baidu.com'); console.log('1'); element(by.css('#kw')).sendKeys('protractor').then(() => {

问题 In the pre-async days, people wanted to know how to set the timeout on WebClient and the answer was simply to extend the base class and override GetWebRequest() and set the timeout there. protected override WebRequest GetWebRequest(Uri address) { // NOTE: this override has no affect if the Async methods are used!!! WebRequest request = base.GetWebRequest(address); ((HttpWebRequest)request).Timeout = 20 * 60 * 1000; ((HttpWebRequest)request).ReadWriteTimeout = 20 * 60 * 1000; return request; }