async-await

问题 Consider this code that runs on the UI thread: dividends = await Database.GetDividends(); if (IsDisposed) return; //Do expensive UI work here earnings = await Database.GetEarnings(); if (IsDisposed) return; //Do expensive UI work here //etc... Note that every time I await I also check IsDisposed . It's necessary because say I await on a long running Task . Meanwhile the user closes the form before it completes. The Task will finish and run a continuation that attempts to access controls on a

问题 Consider this code that runs on the UI thread: dividends = await Database.GetDividends(); if (IsDisposed) return; //Do expensive UI work here earnings = await Database.GetEarnings(); if (IsDisposed) return; //Do expensive UI work here //etc... Note that every time I await I also check IsDisposed . It's necessary because say I await on a long running Task . Meanwhile the user closes the form before it completes. The Task will finish and run a continuation that attempts to access controls on a

问题 Introduction Hey there, I am trying to pass out data from the mongoose withTransaction callback. Right now, I am using the following code which implements callbacks: const transactionSession = await mongoose.startSession() await transactionSession.withTransaction(async (tSession) => { try { // MARK Transaction writes & reads removed for brevity console.log("Successfully performed transaction!") cb(null, "Any test data") return Promise.resolve() } catch (error) { console.log("Transaction

问题 Introduction Hey there, I am trying to pass out data from the mongoose withTransaction callback. Right now, I am using the following code which implements callbacks: const transactionSession = await mongoose.startSession() await transactionSession.withTransaction(async (tSession) => { try { // MARK Transaction writes & reads removed for brevity console.log("Successfully performed transaction!") cb(null, "Any test data") return Promise.resolve() } catch (error) { console.log("Transaction

问题 So I wrote a quick async method to get some data into a DataTable from an Oracle db. How am I suppose to call this from MainWindow() without blocking UI thread? The async / wait model doesn't really make much sense there. async Task<DataTable> AccessOracleAsync() { DataTable dt; using(OracleConnection conn = new OracleConnection(ConfigurationManager.ConnectionStrings["connStr"].ConnectionString)) using (OracleCommand cmd = new OracleCommand(@"SELECT * FROM myTbl", conn)) { await conn

问题 So I wrote a quick async method to get some data into a DataTable from an Oracle db. How am I suppose to call this from MainWindow() without blocking UI thread? The async / wait model doesn't really make much sense there. async Task<DataTable> AccessOracleAsync() { DataTable dt; using(OracleConnection conn = new OracleConnection(ConfigurationManager.ConnectionStrings["connStr"].ConnectionString)) using (OracleCommand cmd = new OracleCommand(@"SELECT * FROM myTbl", conn)) { await conn

问题 So I wrote a quick async method to get some data into a DataTable from an Oracle db. How am I suppose to call this from MainWindow() without blocking UI thread? The async / wait model doesn't really make much sense there. async Task<DataTable> AccessOracleAsync() { DataTable dt; using(OracleConnection conn = new OracleConnection(ConfigurationManager.ConnectionStrings["connStr"].ConnectionString)) using (OracleCommand cmd = new OracleCommand(@"SELECT * FROM myTbl", conn)) { await conn

问题 Just created a WPF project .net 4.6 And have put this code inside lbl1 is a label on the GUI But the label is never updated or the while loop continue only 1 time private void Button_Click_1(object sender, RoutedEventArgs e) { var t = Task.Run( async () => { await AsyncLoop(); }); } async Task AsyncLoop() { while (true) { string result = await LoadNextItem(); lbl1.Content = result; } } private static int ir11 = 0; async Task<string> LoadNextItem() { ir11++; return "aa " + ir11; } 回答1: Please

问题 I have the following test case: it("should pass the test", async function (done) { await asyncFunction(); true.should.eq(true); done(); }); Running it asserts: Error: Resolution method is overspecified. Specify a callback or return a Promise; not both. And if I remove the done(); statement, it asserts: Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. How to solve this paradox? 回答1: You need to remove the done

问题 I have the following code: // Get all of the files from the local storage directory. var files = await folder.GetFilesAsync(); // Map each file to a stream corresponding to that file. var streams = files.Select(async f => { return await f.OpenStreamForWriteAsync(); }); I would expect streams to be of type IEnumerable<Stream> but in fact it is of IEnumberable<Task<Stream>> , which is what I would've expected had I omitted the await keyword. The return type of OpenStreamForWriteAsync is Task