c# 后台任务自动执行

如果有些任务需要在后台自动执行，且时不时需要添加一个任务，且按照优先级顺序执行，那么可以参考本文的方法。

后台任务类

定义一个后台任务类BackgroundTaskThread，其中Start方法是用来启动任务的，循环查询是否有添加任务，外部一般就调用AppendTask来添加任务。循环任务发现任务有添加后，会自动执行。如果有多个任务，会按加入的顺序一个一个执行。

public class BackgroundTaskThread
{/// <summary>/// 任务列表/// </summary>private List<TaskItem> TaskItems = new List<TaskItem>();/// <summary>/// 等待时间/// </summary>public int MillSeconds = 1000;/// <summary>/// 自动重置/// </summary>public AutoResetEvent TaskSet = new AutoResetEvent(false);/// <summary>/// 任务取消标识/// </summary>public CancellationTokenSource Source { get; set; } = new CancellationTokenSource();/// <summary>/// 日志/// </summary>public ILog Log { get; set; }/// <summary>/// 线程数量/// </summary>public int ThreadNum { get; private set; }/// <summary>/// 任务线程/// </summary>public List<Task> TaskThreads = new List<Task>();/// <summary>/// 启动/// </summary>/// <param name="taskTimeSpan">任务扫描间隔</param>/// <param name="taskNum">任务数量</param>public void Start(int taskTimeSpan, int taskNum){ThreadNum = taskNum;for (int i = 0; i < taskNum; i++){MillSeconds = taskTimeSpan;Task task = new Task(BackgroundThread);task.Start();TaskThreads.Add(task);}}/// <summary>/// 后台任务/// </summary>private void BackgroundThread(){try{while (!Source.Token.IsCancellationRequested){var item = GetOrSetTaskItem(true, null);if(item == null){TaskSet.WaitOne(MillSeconds);}else{try{item.Task.Invoke(item.Param);}catch (Exception ex){Log.error("任务 : ", item.Name, " 异常停止.,..", ex);}}}}catch (Exception ex){Log.error("后台任务线程异常退出....", ex);}}/// <summary>/// 读取或者/// </summary>/// <param name="isGet">是否是获取</param>/// <param name="item">任务项</param>/// <returns></returns>protected TaskItem GetOrSetTaskItem(bool isGet, TaskItem item){lock (this){if (isGet){if (TaskItems.Count == 0)return null;item = TaskItems[0];TaskItems.RemoveAt(0);return item;}else{TaskItems.Add(item);return item;}}}/// <summary>/// 追加任务/// </summary>/// <param name="task"></param>/// <param name="param"></param>public void AppendTask(Action<object> task, object param){GetOrSetTaskItem(false, new TaskItem() { Task = task, Param = param });TaskSet.Set();}/// <summary>/// 释放/// </summary>public void Dispose(){if(TaskThreads.Count > 0)Source.Cancel();TaskItems.Clear();}
}

内部任务定义类

public class TaskItem
{/// <summary>/// 任务/// </summary>public Action<object> Task { get; set; }/// <summary>/// 参数/// </summary>public object Param { get; set; }/// <summary>/// 任务名称/// </summary>public string Name { get; set; } = string.Empty;
}

实际任务

public class DoSomethingTaskThread : BackgroundTaskThread
{public void AppendSomething(object data){AppendTask(DoSomething, data);}private void DoSomething(object data){//TODO}
}

外部调用

当然，最好把DoSomethingTaskThread这个子类做成单例，后面直接

//启动任务，同步的话线程数传1，异步的话线程数可以传多点
DoSomethingTaskThread.Start(1000,1);//添加任务
DoSomethingTaskThread.AppendSomething(new object());