内容简介:翻译自:https://stackoverflow.com/questions/15119974/creating-backgroundworker-with-queue
我需要创建队列并将其与BackgroundWorker一起使用.所以我可以添加操作,然后在下一步完成时将在后台启动.我通过谷歌找到了这个代码:
public class QueuedBackgroundWorker<T>
{
public void QueueWorkItem(
Queue queue,
T inputArgument,
Func<T> doWork,
Action workerCompleted)
{
if (queue == null) throw new ArgumentNullException("queue");
BackgroundWorker bw = new BackgroundWorker();
bw.WorkerReportsProgress = false;
bw.WorkerSupportsCancellation = false;
bw.DoWork += (sender, args) =>
{
if (doWork != null)
{
args.Result = doWork(new DoWorkArgument<T>((T)args.Argument));
}
};
bw.RunWorkerCompleted += (sender, args) =>
{
if (workerCompleted != null)
{
workerCompleted(new WorkerResult<T>((T)args.Result, args.Error));
}
queue.Dequeue();
if (queue.Count > 0)
{
QueueItem<T> nextItem = queue.Peek() as QueueItem<T>;
nextItem.BackgroundWorker.RunWorkerAsync(nextItem.Argument);
}
};
queue.Enqueue(new QueueItem<T>(bw, inputArgument));
if (queue.Count == 1)
{
QueueItem<T> nextItem = queue.Peek() as QueueItem<T>;
nextItem.BackgroundWorker.RunWorkerAsync(nextItem.Argument);
}
}
}
public class DoWorkArgument<T>
{
public DoWorkArgument(T argument)
{
this.Argument = argument;
}
public T Argument { get; private set; }
}
public class WorkerResult<T>
{
public WorkerResult(T result, Exception error)
{
this.Result = result;
this.Error = error;
}
public T Result { get; private set; }
public Exception Error { get; private set; }
}
public class QueueItem<T>
{
public QueueItem(BackgroundWorker backgroundWorker, T argument)
{
this.BackgroundWorker = backgroundWorker;
this.Argument = argument;
}
public T Argument { get; private set; }
public BackgroundWorker BackgroundWorker { get; private set; }
}
但我有doWork和workerCompleted的问题.我收到错误:
Delegate ‘Func’ does not take 1 arguments
我怎样才能解决这个问题?我该如何更改参数?谢谢
这是一个更短的方法,可以满足您的需求:
public class BackgroundQueue
{
private Task previousTask = Task.FromResult(true);
private object key = new object();
public Task QueueTask(Action action)
{
lock (key)
{
previousTask = previousTask.ContinueWith(t => action()
, CancellationToken.None
, TaskContinuationOptions.None
, TaskScheduler.Default);
return previousTask;
}
}
public Task<T> QueueTask<T>(Func<T> work)
{
lock (key)
{
var task = previousTask.ContinueWith(t => work()
, CancellationToken.None
, TaskContinuationOptions.None
, TaskScheduler.Default);
previousTask = task;
return task;
}
}
}
通过添加每个新动作作为前一个的延续,您确保一次只能处理一个,因为下一个项目在上一个项目完成之前不会启动,您确保在那里没有任何线程坐在空闲处没有什么可以解决的,你确保他们都按顺序完成.
另请注意,如果您认为自己只需要一个队列而不需要任何数字,那么您可以将所有成员设置为静态,但这取决于您.
翻译自:https://stackoverflow.com/questions/15119974/creating-backgroundworker-with-queue
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