fix(#IZOW4): 增加TasksExtensions扩展任务示例

#Comment
comment #IZOW4
增加 TasksExtensions 扩展方法，调用 services.AddHostedService<TaskBackgroundServices>()

#Issue
close https://gitee.com/LongbowEnterprise/dashboard/issues?id=IZOW4

Bootstrap.Admin/Controllers/Api/TasksController.cs

@@ -21,11 +21,6 @@ namespace Bootstrap.Admin.Controllers.Api
         [HttpGet]
         public IEnumerable<object> Get()
         {
-            TaskServicesManager.GetOrAdd("单次任务", token => Task.Delay(1000));
-            TaskServicesManager.GetOrAdd("周期任务", token => Task.Delay(1000), TriggerBuilder.Build(Cron.Secondly(5)));
-            TaskServicesManager.GetOrAdd("超时任务", token => Task.Delay(2000), TriggerBuilder.Default.WithTimeout(1000).WithInterval(1000).WithRepeatCount(2).Build());
-            TaskServicesManager.GetOrAdd("故障任务", token => throw new Exception("故障任务"));
-            TaskServicesManager.GetOrAdd("取消任务", token => Task.Delay(1000)).Triggers.First().Enabled = false;
             return TaskServicesManager.ToList().Select(s => new { s.Name, Status = s.Status.ToString(), s.LastRuntime, s.CreatedTime, s.NextRuntime, LastRunResult = s.Triggers.First().LastResult.ToString(), TriggerExpression = s.Triggers.FirstOrDefault().ToString() }).OrderBy(s => s.Name);
         }
     }

Bootstrap.Admin/Startup.cs

@@ -63,7 +63,7 @@ namespace Bootstrap.Admin
             services.AddBootstrapAdminAuthentication();
             services.AddSwagger();
             services.AddButtonAuthorization();
-            services.AddTaskServices();
+            services.AddDemoTask();
             services.AddMvc(options =>
             {
                 options.Filters.Add<BootstrapAdminAuthorizeFilter>();

Bootstrap.Admin/Tasks/TasksExtensions.cs

@@ -0,0 +1,45 @@
+using Longbow.Tasks;
+using Microsoft.Extensions.Hosting;
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.Extensions.DependencyInjection
+{
+    /// <summary>
+    /// 后台任务扩展方法
+    /// </summary>
+    internal static class TasksExtensions
+    {
+        /// <summary>
+        /// 添加示例后台任务
+        /// </summary>
+        /// <param name="services"></param>
+        public static IServiceCollection AddDemoTask(this IServiceCollection services)
+        {
+            services.AddHostedService<TaskBackgroundServices>();
+            return services.AddTaskServices();
+        }
+    }
+
+    /// <summary>
+    /// 后台任务服务类
+    /// </summary>
+    internal class TaskBackgroundServices : BackgroundService
+    {
+        /// <summary>
+        /// 运行任务
+        /// </summary>
+        /// <param name="stoppingToken"></param>
+        /// <returns></returns>
+        protected override Task ExecuteAsync(CancellationToken stoppingToken) => Task.Run(() =>
+        {
+            TaskServicesManager.GetOrAdd("单次任务", token => Task.Delay(1000));
+            TaskServicesManager.GetOrAdd("周期任务", token => Task.Delay(1000), TriggerBuilder.Build(Cron.Secondly(5)));
+            TaskServicesManager.GetOrAdd("超时任务", token => Task.Delay(2000), TriggerBuilder.Default.WithTimeout(1000).WithInterval(1000).WithRepeatCount(2).Build());
+            TaskServicesManager.GetOrAdd("故障任务", token => throw new Exception("故障任务"));
+            TaskServicesManager.GetOrAdd("取消任务", token => Task.Delay(1000)).Triggers.First().Enabled = false;
+        });
+    }
+}