async await

Author: Anton Wieslander

Async Await Task/AsyncAwait/AsyncAwait.sln renamed to Async Await Task Explained/AsyncAwait/AsyncAwait.sln

@@ -0,0 +1,37 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30011.22
+MinimumVisualStudioVersion = 10.0.40219.1
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+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WhereDoesItStart", "WhereDoesItStart\WhereDoesItStart.csproj", "{23C26454-BEA0-4080-B77E-F4D0338BAD24}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WpfApp", "WpfApp\WpfApp.csproj", "{F5C53ADB-5A4E-4D8D-97F7-5070AF2CFCC0}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{7F157BFA-1063-42D8-9E8A-6C74C7B630F5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7F157BFA-1063-42D8-9E8A-6C74C7B630F5}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7F157BFA-1063-42D8-9E8A-6C74C7B630F5}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7F157BFA-1063-42D8-9E8A-6C74C7B630F5}.Release|Any CPU.Build.0 = Release|Any CPU
+		{23C26454-BEA0-4080-B77E-F4D0338BAD24}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{23C26454-BEA0-4080-B77E-F4D0338BAD24}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{23C26454-BEA0-4080-B77E-F4D0338BAD24}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{23C26454-BEA0-4080-B77E-F4D0338BAD24}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F5C53ADB-5A4E-4D8D-97F7-5070AF2CFCC0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F5C53ADB-5A4E-4D8D-97F7-5070AF2CFCC0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F5C53ADB-5A4E-4D8D-97F7-5070AF2CFCC0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F5C53ADB-5A4E-4D8D-97F7-5070AF2CFCC0}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {827DE696-34F9-410F-84C9-EF06D2337BA5}
+	EndGlobalSection
+EndGlobal

Async Await Task/AsyncAwait/AsyncAwait/AsyncAwait.csproj renamed to Async Await Task Explained/AsyncAwait/AsyncAwait/AsyncAwait.csproj

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+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace WebApp.Controllers
+{
+    public class AvoidStateMachine : Controller
+    {
+        public async Task<ActionResult> Index()
+        {
+            var a = await InputOutputN();
+            return View(a);
+        }
+
+
+        public async Task<string> InputOutputN()
+        {
+            var client = new HttpClient();
+            var content = await client.GetStringAsync("some site");
+            // do something with the content
+
+            return content;
+        }
+
+        public Task<string> InputOutputNA()
+        {
+            var client = new HttpClient();
+            return client.GetStringAsync("some site");
+        }
+
+        public Task<string> InputOutput()
+        {
+            var message = "Hello World";
+            return Task.FromResult(message);
+        }
+
+        public Task InputOutputC()
+        {
+            return Task.CompletedTask;
+        }
+    }
+}

Async Await Task/AsyncAwait/AsyncAwait/Program.cs renamed to Async Await Task Explained/AsyncAwait/AsyncAwait/Program.cs

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+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace WebApp.Controllers
+{
+    public class DoesntMatterWhichThread : Controller
+    {
+        public IActionResult Index()
+        {
+            return View();
+        }
+
+        public async Task<string> InputOutput()
+        {
+            var client = new HttpClient();
+            var content = await client.GetStringAsync("some site")
+                .ConfigureAwait(false);
+
+            return content;
+        }
+    }
+}

Async Await Task/making_tea_analogy.linq renamed to Async Await Task Explained/making_tea_analogy.linq

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+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace WebApp.Controllers
+{
+    public class DontAsyncInConstructor : Controller
+    {
+        public IActionResult Index()
+        {
+            return View();
+        }
+
+        public Task<string> InputOutput()
+        {
+
+        }
+    }
+
+    public class SomeObject
+    {
+        public SomeObject()
+        {
+            //never do async here.
+        }
+
+        public static async Task<SomeObject> Create()
+        {
+            return new SomeObject();
+        }
+    }
+
+    public class SomeObjectFactory
+    {
+        public SomeObjectFactory()
+        {
+
+        }
+
+        public async Task<SomeObject> Create()
+        {
+            return new SomeObject();
+        }
+    }
+}

Async Await Task/what_thread_are_we_on.linq renamed to Async Await Task Explained/what_thread_are_we_on.linq

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+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace WebApp.Controllers
+{
+    public class DontBlockTheThread : Controller
+    {
+        public IActionResult Index()
+        {
+            var task = InputOutput();
+
+            //BAD
+            var a = task.Result;
+
+            //BAD
+            task.Wait();
+
+            //BAD
+            task.GetAwaiter().GetResult();
+
+            //solution is to propagate async await task throught your code
+
+            return View();
+        }
+
+        public Task<string> InputOutput()
+        {
+            var client = new HttpClient();
+            return client.GetStringAsync("some site");
+        }
+    }
+}