正如标题所示,我在异步使用的ObjectDisposedException
上调用"Abort"
似乎得到了HttpWebRequest
(即BeginGetResponse
),而不是我的生活,弄清楚如何防止它。我花了一整天寻找解决方案,所以任何帮助将不胜感激。这是一个说明问题的简单示例:
// helper class that gets passed through as the state
class RequestState
{
public HttpWebRequest Request { get; set; }
public bool TimedOut { get; set; }
}
class Program
{
static void Main(string[] args)
{
var rs = new RequestState
{
Request = (HttpWebRequest)WebRequest.Create("http://google.com")
};
var result = rs.Request.BeginGetResponse(
asyncResult =>
{
if (asyncResult.IsCompleted)
{
var reqState = asyncResult.AsyncState as RequestState;
if (reqState != null && !reqState.TimedOut)
{
using (var response = reqState.Request.EndGetResponse(asyncResult) as HttpWebResponse)
{
using (var streamReader = new StreamReader(response.GetResponseStream()))
{
Console.WriteLine(streamReader.ReadToEnd());
}
}
}
else
{
Console.WriteLine("Timed out!");
}
}
},
rs);
ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle,
(state, timeout) =>
{
if (timeout)
{
var temprs = state as RequestState;
if (temprs != null)
{
// set TimedOut flag
temprs.TimedOut = true;
// this will cause the BeginGetResponse callback above to be called
temprs.Request.Abort();
}
// after this method leaves scope the ObjectDisposedException occurs!
}
},
// time out of 7 seconds
rs, 7000, true);
Console.ReadLine();
}
}
这是我正在做的事情:
如果我正常运行,响应就会很好地写入控制台。但是,如果我使用Fiddler模拟慢速互联网连接(或基本上没有连接)并执行超时回调,我会得到前面提到的ObjectDisposedException
("Timed out!"
首先写入控制台)。如果我不在Abort
上致电HttpWebRequest
,我就不会收到此异常。
谁能告诉我我做错了什么?我的目标是.NET 3.5框架。提前感谢您的任何启示。
这是异常信息/调用堆栈:
System.ObjectDisposedException occurred
Message=Cannot access a disposed object.
Object name: 'System.Net.Sockets.NetworkStream'.
Source=System
ObjectName=System.Net.Sockets.NetworkStream
StackTrace:
at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
InnerException:
System.Net.Sockets.NetworkStream.EndRead(System.IAsyncResult asyncResult) + 0x1b7 bytes
System.Net.PooledStream.EndRead(System.IAsyncResult asyncResult) + 0x10 bytes
System.Net.Connection.ReadCallback(System.IAsyncResult asyncResult) + 0x33 bytes
System.Net.Connection.ReadCallbackWrapper(System.IAsyncResult asyncResult) + 0x46 bytes
System.Net.LazyAsyncResult.Complete(System.IntPtr userToken) + 0x69 bytes
System.Net.ContextAwareResult.Complete(System.IntPtr userToken) + 0xab bytes
System.Net.LazyAsyncResult.ProtectedInvokeCallback(object result, System.IntPtr userToken) + 0xb0 bytes
System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(uint errorCode, uint numBytes, System.Threading.NativeOverlapped* nativeOverlapped) + 0x94 bytes
System.Threading._IOCompletionCallback.PerformIOCompletionCallback(uint errorCode, uint numBytes, System.Threading.NativeOverlapped* pOVERLAP) + 0x54 bytes