如何创建一个观察来自 FileSystemWatcher 的 `Renamed` 和 `Changed` 事件的 `Observable`

Question

我想创建一个ReactiveObservable，可以同时观察Renamed和Changed

我正在使用 FileSystemWatcher 监控文件夹中的修改和重命名文件。我只想在事件稳定下来后处理它（因为有时 Changed 事件可能会引发多次）。所以我选择.net的Reactive Extension.

的Throttle函数

我可以通过观察单个 Changed 事件来设法完成这项工作，但无法弄清楚如何在单个 [=15= 中观察 Changed 和 Renamed ].

这是我为单个 Changed 事件所做的：

var watcher = new FileSystemWatcher();
watcher.Path = "d:\test";
var observable = Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
                            ev => watcher.Changed += ev,
                            ev => watcher.Changed -= ev
);

var d = observable.Throttle(TimeSpan.FromSeconds(5))
                    .Subscribe(
                        a => Console.WriteLine($"Watcher type:{a.EventArgs.ChangeType }, file:{a.EventArgs.Name }, sender: {a.Sender}"),
                        ex => Console.WriteLine("observer error:" + ex.ToString()),
                        () => Console.WriteLine("observer complete.")
                );

但是当我想同时观看这两个事件时，VS 告诉我 FileSystemEventHandler 和 RenamedEventHandler 不兼容（尽管 RenamedEventArgs 可以安全地转换为 FileSystemEventArgs):

var observable = Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
                            ev => { 
                            watcher.Changed += ev; 
                            //Error
                            watcher.Renamed += ev; 
                            },
                            ev => { 
                            watcher.Changed -= ev; 
                            //Error
                            watcher.Renamed -= ev; 
                            });

我知道我可以将 ev 转换为兼容的委托，但我想知道如何记录该委托并将其从事件中删除？因为我读到匿名委托不能从 event 中删除，除非在注册时记录它（如（此问题）[Adding and Removing Anonymous Event Handler 中所述）。 Aslo，这样做同样一点也不优雅...

Func<FileSystemEventHandler, RenamedEventHandler> renameDelegate = (FileSystemEventHandler h) =>
                {
                    return (object sender, RenamedEventArgs args) => h(sender, args);
                };
var observable = Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
                            ev => { watcher.Changed += ev; 
                                    //registered delegate
                                    watcher.Renamed += renameDelegate(ev); 
                                    },
                            ev => { watcher.Changed -= ev; 
                                    //this seems not to be identical with the one registered
                                    watcher.Renamed -= renameDelegate(ev); });
                );

那么我如何在同一个 Observable 中同时观察 Changed 和 Renamed 事件？

编辑 1

感谢@Enigmativity 的回答，我的最终代码如下（示例代码）：

var o1 = Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
                            ev => watcher.Changed += ev,
                            ev => watcher.Changed -= ev);
var o2 = Observable.FromEventPattern<RenamedEventHandler, RenamedEventArgs>(
                            ev => watcher.Renamed += ev,
                            ev => watcher.Renamed -= ev)
                    .Select(x => new System.Reactive.EventPattern<FileSystemEventArgs>(x.Sender, x.EventArgs));

var o = Observable.Merge(o1, o2);

var d = o.Throttle(TimeSpan.FromSeconds(5))
                    .Subscribe(
                        a => Console.WriteLine($"Watcher type:{a.EventArgs.ChangeType }, file:{a.EventArgs.Name }, sender: {a.Sender}"),
                        ex => Console.WriteLine("observer error:" + ex.ToString()),
                        () => Console.WriteLine("observer complete.")

Answer 1

操作方法如下：

var observable =
    Observable
        .Using(
            () => new FileSystemWatcher() { Path = "d:\test" },
            watcher =>
                Observable
                    .Merge(
                        Observable
                            .FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
                                ev => watcher.Changed += ev,
                                ev => watcher.Changed -= ev)
                            .Select(x => new
                            {
                                x.EventArgs.Name,
                                x.EventArgs.FullPath,
                                x.EventArgs.ChangeType,
                                OldName = (string)null,
                                OldFullPath = (string)null,
                            }),
                        Observable
                            .FromEventPattern<RenamedEventHandler, RenamedEventArgs>(
                                ev => watcher.Renamed += ev,
                                ev => watcher.Renamed -= ev)
                            .Select(x => new
                            {
                                x.EventArgs.Name,
                                x.EventArgs.FullPath,
                                x.EventArgs.ChangeType,
                                x.EventArgs.OldName,
                                x.EventArgs.OldFullPath
                            })));

如何创建一个观察来自 FileSystemWatcher 的 `Renamed` 和 `Changed` 事件的 `Observable`

How to create a `Observable` which observes both `Renamed` and `Changed` events from `FileSystemWatcher`

.net-core

system.reactive

filesystemwatcher

编辑 1