我想创建一个在我键入时使用 linq 搜索的任务,如果用户键入另一个字符,它应该取消任务并重新创建搜索,我有以下代码:
private Task SearchChannels;
private CancellationTokenSource cancelSearch;
public void PopulateChannels(string newValue)
{
IsSearchingChannels = true; //This just shows a progressbar
if (SearchChannels != null && cancelSearch!= null)
if (SearchChannels.Status == TaskStatus.Running ||
SearchChannels.Status == TaskStatus.WaitingToRun ||
SearchChannels.Status == TaskStatus.WaitingForActivation ||
SearchChannels.Status == TaskStatus.WaitingForChildrenToComplete)
{
cancelSearch.Cancel();
SearchChannels.Wait();
}
cancelSearch = new CancellationTokenSource();
SearchChannels = new Task(() => Channels = new PagedObservableCollection<Channel>(ContractManager.Channels.Where(x => x.Name.ToLower().StartsWith(newValue)).AsParallel().WithCancellation(cancelSearch.Token).ToList()), cancelSearch.Token); //PagedObservableCollection is just a simple class with a list that keeps all items and an ObservableCollection for current items shown
SearchChannels.Start();
SearchChannels.ContinueWith((continuation) => IsSearchingChannels = false); // this just hides the progressbar when done
}
我得到这个例外:
'System.OperationCanceledException'
发生类型异常System.Core.dll
但未在用户代码中处理
附加信息:操作已取消。
我是任务和取消令牌的初学者,有人可以从这里引导我走正确的道路吗?我基本上希望任务检查它是否已经运行,取消它,然后使用新值再次运行它(我想让这个“SearchBox”功能类似于 Visual Studio 在解决方案资源管理器中的搜索,它会在你输入时搜索)