C # Asynchronous Programming (i): Asynchronous basics

classProgram {Static voidMain (string[] args) {            varresult = Downloadstringwithtimeout ("http://www.yueyangdujia.com"); Console.WriteLine ("Asynchronous Method Execution");  for(inti =0; I <3; i++) {System.Threading.Thread.Sleep ( +); Console.WriteLine ("Take a break."+ (i+1)+"seconds"); }                 varstr= result. Result;//this uses the return value of the Async method and waits for the asynchronous method to execute. Console.WriteLine ("after the Async method executes, the following code is executed synchronously");            Console.WriteLine (str);        Console.read (); }        Static Asynctask<string> Downloadstringwithtimeout (stringURI) {            using(varClient=NewHttpClient ()) {                varDownloadtask =client.                Getstringasync (URI); varTimeouttask = Task.delay ( the); varCompletedtask =awaitTask.whenany (Downloadtask, Timeouttask); if(Completedtask = =timeouttask) {System.Threading.Thread.Sleep ( -); Console.WriteLine ("asynchronous method Execution Complete"); return NULL; } System.Threading.Thread.Sleep ( -); Console.WriteLine ("asynchronous method Execution Complete"); return awaitDownloadtask; }                    }    }

The execution order is shown as Console.WriteLine. The downloadstringwithtimeout is executed with the following code, approximately 2 seconds. var str= result. Result; The asynchronous method will wait for the async method to execute when it calls the return value.

Down to remove some code as follows:

    classProgram {Static voidMain (string[] args) {            varresult = Downloadstringwithtimeout ("http://www.yueyangdujia.com"); varstr= result. Result;//this uses the return value of the Async method and waits for the asynchronous method to execute. Console.WriteLine (str);        Console.read (); }        Static Asynctask<string> Downloadstringwithtimeout (stringURI) {            using(varClient=NewHttpClient ()) {                varDownloadtask =client.                Getstringasync (URI); varTimeouttask = Task.delay ( the); varCompletedtask =awaitTask.whenany (Downloadtask, Timeouttask); if(Completedtask = =timeouttask) {                                    return NULL; }                return awaitDownloadtask; }                    }    }

Whenany accepts two async method parameters to return the first executed method. The above can adjust the parameters of the Task.delay. Returns null if it is small enough.

C # Asynchronous Programming (i): Asynchronous basics