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[英]Which event fires when we cancel some App by Windows Task Manager?
[英]Complete a task when an event fires
这应该很简单,但我就是无法集中注意力。
在这个方法中
public static async Task<string> UnloadAsync(Assembly assy, bool silentFail = false)
{
if (AssyLoadContext.__alcd.ContainsKey(assy))
{
var assemblyName = __namd.Where(kvp => kvp.Value == assy).First().Key;
__alcd[assy].Unloading += alc => //signal the task to complete and return assemblyName
__namd.Remove(assemblyName);
__alcd[assy].Unload();
__alcd.Remove(assy);
Debug.WriteLine($"Unloaded assembly '{assy.GetName().Name}'");
}
if (silentFail)
{
return null;
}
else
{
throw new InvalidOperationException($"Assembly '{assy.GetName().Name}' cannot be unloaded. Did you load it using AssyLoadContext.LoadWithPrivateContext(string assyPath)?");
}
}
AssemblyLoadContext.Unload()
操作实际上是异步的,但不可等待。 一旦没有更多的强 GC 引用等操作完成,程序集就会卸载并触发 Unloading 事件。
返回值在我想提供给延续的assemblyName
中。
我能找到的所有文档都在谈论需要await
,因为那是收益发生的地方,但我不能那样写。 你如何在没有await
的情况下做到这一点?
您正在寻找一个TaskCompletionSource<string>
:
public static Task<string> UnloadAsync(Assembly assy, bool silentFail = false)
{
if (AssyLoadContext.__alcd.ContainsKey(assy))
{
var tcs = new TaskCompletionSource<string>();
var assemblyName = __namd.Where(kvp => kvp.Value == assy).First().Key;
__alcd[assy].Unloading += alc => tcs.SetResult(assemblyName);
__namd.Remove(assemblyName);
__alcd[assy].Unload();
__alcd.Remove(assy);
Debug.WriteLine($"Unloaded assembly '{assy.GetName().Name}'");
return tcs.Task;
}
if (silentFail)
{
return Task.FromResult<string>(null);
}
throw new InvalidOperationException($"Assembly '{assy.GetName().Name}' cannot be unloaded. Did you load it using AssyLoadContext.LoadWithPrivateContext(string assyPath)?");
}
}
请注意,如果这引发InvalidOperationException
,它会在调用UnloadAsync
时被抛出,而不是被包装在返回的Task
中(如果您的方法是async
会发生这种情况)。 如果你想改变它,你可以使用 TaskCompletionSource:
public static Task<string> UnloadAsync(Assembly assy, bool silentFail = false)
{
var tcs = new TaskCompletionSource<string>();
if (AssyLoadContext.__alcd.ContainsKey(assy))
{
var assemblyName = __namd.Where(kvp => kvp.Value == assy).First().Key;
__alcd[assy].Unloading += alc => tcs.SetResult(assemblyName);
__namd.Remove(assemblyName);
__alcd[assy].Unload();
__alcd.Remove(assy);
Debug.WriteLine($"Unloaded assembly '{assy.GetName().Name}'");
}
else if (silentFail)
{
tcs.SetResult(null);
}
else
{
tcs.SetException(throw new InvalidOperationException($"Assembly '{assy.GetName().Name}' cannot be unloaded. Did you load it using AssyLoadContext.LoadWithPrivateContext(string assyPath)?"));
}
return tcs.Task;
}
或者使用async
方法:
public static async Task<string> UnloadAsync(Assembly assy, bool silentFail = false)
{
if (AssyLoadContext.__alcd.ContainsKey(assy))
{
var tcs = new TaskCompletionSource<string>();
var assemblyName = __namd.Where(kvp => kvp.Value == assy).First().Key;
__alcd[assy].Unloading += alc => tcs.SetResult(assemblyName);
__namd.Remove(assemblyName);
__alcd[assy].Unload();
__alcd.Remove(assy);
Debug.WriteLine($"Unloaded assembly '{assy.GetName().Name}'");
return await tcs.Task;
}
if (silentFail)
{
return null;
}
throw new InvalidOperationException($"Assembly '{assy.GetName().Name}' cannot be unloaded. Did you load it using AssyLoadContext.LoadWithPrivateContext(string assyPath)?");
}
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