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分享如何使用WebClient类的UploadDataAsync方法进行带进度条的FTP循环异步上传
RT，进度条和循环我已经搞好了，现在的问题是，如何让程序等待当前循环运行完毕后再进入下一个循环？
我用了WaitOne方法，根据MSDN上这个实例，不过怎么调试都得不出“File upload is complete.”这个结果，上传开始后程序直接就卡死了。查看FTP发现图片上传已经成功了，不过程序却无法返回结果。
我用了WaitOne方法，根据MSDN上这个实例，不过怎么调试都得不出“File upload is complete.”这个结果，上传开始后程序直接就卡死了。查看FTP发现图片上传已经成功了，不过程序却无法返回结果。
Public Shared Sub UploadFileInBackground(ByVal address As String, ByVal fileName As String)
Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(False)
Dim client As WebClient = New WebClient()
Dim method As String = "STOR"
Dim uri as Uri = New Uri(address)
' Specify that that UploadFileCallback method gets called
' when the file upload completes.
AddHandler client.UploadFileCompleted, AddressOf UploadFileCallback
client.UploadFileAsync(uri, method, fileName, waiter)
' Block the main application thread. Real applications
' can perform other tasks while waiting for the upload to complete.
waiter.WaitOne()
Console.WriteLine("File upload is complete.")
End Sub
Public Shared Sub UploadFileCallback(ByVal sender As Object, ByVal e As System.Net.UploadFileCompletedEventArgs)
Dim waiter As System.Threading.AutoResetEvent = CType(e.UserState, System.Threading.AutoResetEvent)
Try
Dim reply As String = System.Text.Encoding.UTF8.GetString(e.Result)
Console.WriteLine(reply)
Finally
' If this thread throws an exception, make sure that
' you let the main application thread resume.
waiter.Set()
End Try
End Sub
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xwchenhui001 2010-04-29
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[Quote=引用 7 楼 xingyuebuyu 的回复:]
上传不了是什么意思？
我这里没环境进行测试，不过你要循环上传，最好是在UploadFileCallback方法中开始下一次的上传，用数组存你要上传的地址和文件名，这样就不用循环等待。
[/Quote]
不是，我原本打算换成UploadDataAsync方法上传的，不过搞不定代码，所以上传不了。现在换回来了，有时间再研究那个。
在UploadFileCallback方法中开始下一次的上传，这个思路不错，我试试看，谢谢了
上传不了是什么意思？
我这里没环境进行测试，不过你要循环上传，最好是在UploadFileCallback方法中开始下一次的上传，用数组存你要上传的地址和文件名，这样就不用循环等待。
[/Quote]
不是，我原本打算换成UploadDataAsync方法上传的，不过搞不定代码，所以上传不了。现在换回来了，有时间再研究那个。
在UploadFileCallback方法中开始下一次的上传，这个思路不错，我试试看，谢谢了
xingyuebuyu 2010-04-29
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上传不了是什么意思？
我这里没环境进行测试，不过你要循环上传，最好是在UploadFileCallback方法中开始下一次的上传，用数组存你要上传的地址和文件名，这样就不用循环等待。
我这里没环境进行测试，不过你要循环上传，最好是在UploadFileCallback方法中开始下一次的上传，用数组存你要上传的地址和文件名，这样就不用循环等待。
xwchenhui001 2010-04-29
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[Quote=引用 5 楼 xingyuebuyu 的回复:]
VB.NET code
While bolFinish = False
''加入sleep可以降低CPU使用率
System.Threading.Thread.Sleep(20)
Application.DoEvents()
End While
你直接调用UploadFileInBackground方法会阻止不？
仍……
[/Quote]
是我的代码写错了，我单独测试UploadDataAsync的时候发现根本上传不了。不知道还有更好的办法没？这样循环调用Application.DoEvents()有点治标不治本的味道，呵呵
VB.NET code
While bolFinish = False
''加入sleep可以降低CPU使用率
System.Threading.Thread.Sleep(20)
Application.DoEvents()
End While
你直接调用UploadFileInBackground方法会阻止不？
仍……
[/Quote]
是我的代码写错了，我单独测试UploadDataAsync的时候发现根本上传不了。不知道还有更好的办法没？这样循环调用Application.DoEvents()有点治标不治本的味道，呵呵
xingyuebuyu 2010-04-29
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While bolFinish = False
''加入sleep可以降低CPU使用率
System.Threading.Thread.Sleep(20)
Application.DoEvents()
End While
你直接调用UploadFileInBackground方法会阻止不？
仍然分别加入之前的代码看UploadFileInBackground和UploadFileCallback是否是在同一个线程中运行？
Console.WriteLine("Upload Complete thread id " + System.Threading.Thread.CurrentThread.ManagedThreadId.ToString)
xwchenhui001 2010-04-28
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[Quote=引用 3 楼 xingyuebuyu 的回复:]
VB.NET code
Public Shared Sub UploadFileInBackground(ByVal address As String, ByVal fileName As String)
Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(Fa……
[/Quote]
谢谢这位大哥，你的方法确实可行，不过为什么我改用UploadDataAsync的方法就不行了呢？程序执行到最后依然卡住，CPU占用100%
另外，我是在另一个过程中call上传过程的
VB.NET code
Public Shared Sub UploadFileInBackground(ByVal address As String, ByVal fileName As String)
Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(Fa……
[/Quote]
谢谢这位大哥，你的方法确实可行，不过为什么我改用UploadDataAsync的方法就不行了呢？程序执行到最后依然卡住，CPU占用100%
Public Shared bolFinish As Boolean = False
Public Shared Sub UploadFileInBackground(ByVal address As String, ByVal fileName As String)
Dim client As WebClient = New WebClient()
Dim method As String = "STOR"
Dim uri As Uri = New Uri(address)
Dim myStream As FileStream = New FileStream(FilePath, FileMode.Open, FileAccess.Read)
Dim data() As Byte = New Byte(myStream.Length) {}
myStream.Read(Data, 0, myStream.Length)
bolFinish = False
AddHandler client.UploadProgressChanged, New UploadProgressChangedEventHandler(AddressOf Form1.wc_UploadProgressChanged)
AddHandler client.UploadFileCompleted, AddressOf UploadFileCallback
client.UploadDataAsync(uri, method, Data)
'client.UploadFileAsync(uri, method, fileName)
While bolFinish = False
Application.DoEvents()
End While
Console.WriteLine("File upload is complete.")
End Sub
Public Shared Sub UploadFileCallback(ByVal sender As Object, ByVal e As System.Net.UploadFileCompletedEventArgs)
bolFinish = True
End Sub另外，我是在另一个过程中call上传过程的
xingyuebuyu 2010-04-28
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Public Shared Sub UploadFileInBackground(ByVal address As String, ByVal fileName As String)
Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(False)
Dim client As WebClient = New WebClient()
Dim method As String = "STOR"
Dim uri as Uri = New Uri(address)
' Specify that that UploadFileCallback method gets called
' when the file upload completes.
AddHandler client.UploadFileCompleted, AddressOf UploadFileCallback
client.UploadFileAsync(uri, method, fileName, waiter)
' Block the main application thread. Real applications
' can perform other tasks while waiting for the upload to complete.
''waiter.WaitOne()
Console.WriteLine("Upload thread id "+System.Threading.Thread.CurrentThread.ManagedThreadId.ToString)
Console.WriteLine("File upload is complete.")
End Sub
Public Shared Sub UploadFileCallback(ByVal sender As Object, ByVal e As System.Net.UploadFileCompletedEventArgs)
Dim waiter As System.Threading.AutoResetEvent = CType(e.UserState, System.Threading.AutoResetEvent)
Try
Dim reply As String = System.Text.Encoding.UTF8.GetString(e.Result)
Console.WriteLine(reply)
Finally
' If this thread throws an exception, make sure that
' you let the main application thread resume.
Console.WriteLine("Upload Complete thread id " + System.Threading.Thread.CurrentThread.ManagedThreadId.ToString)
''waiter.Set()
End Try
End Sub
你先不使用System.Threading.AutoResetEvent,看下程序运行结果就会发现Upload thread id和
"Upload Complete thread id "是一样的,说明异步上传过程虽然使用的是线程池中的线程,但是上传完成后要回调的函数还是你之前开始异步上传的线程,但是因为你在开始异步上传后使用waiter.WaitOne()
阻止了当前线程,所以线程池中的线程回调你的上传完成函数也被阻止了,无法进行调用.
Public Shared bolFinish As Boolean = False
Public Shared Sub UploadFileInBackground(ByVal address As String, ByVal fileName As String)
'Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(False)
Dim client As WebClient = New WebClient()
Dim method As String = "STOR"
Dim uri As Uri = New Uri(address)
bolFinish = False
' Specify that that UploadFileCallback method gets called
' when the file upload completes.
AddHandler client.UploadFileCompleted, AddressOf UploadFileCallback
client.UploadFileAsync(uri, method, fileName)
While bolFinish = False
Application.DoEvents()
End While
' Block the main application thread. Real applications
' can perform other tasks while waiting for the upload to complete.
'waiter.WaitOne()
Console.WriteLine("File upload is complete.")
End Sub
Public Shared Sub UploadFileCallback(ByVal sender As Object, ByVal e As System.Net.UploadFileCompletedEventArgs)
' Dim waiter As System.Threading.AutoResetEvent = CType(e.UserState, System.Threading.AutoResetEvent)
Try
Dim reply As String = System.Text.Encoding.UTF8.GetString(e.Result)
Console.WriteLine(reply)
Finally
' If this thread throws an exception, make sure that
' you let the main application thread resume.
' waiter.Set()
bolFinish = True
End Try
End Subxwchenhui001 2010-04-28
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汗，没用的。
WaitOne下面的语句是等Set上面的语句运行完后才运行的，跟假死无关。
照理说，图片传完，Set上面的语句应该也运行了，不知道怎么搞的，就是看不到输出结果，程序直接死了。
WaitOne下面的语句是等Set上面的语句运行完后才运行的，跟假死无关。
照理说，图片传完，Set上面的语句应该也运行了，不知道怎么搞的，就是看不到输出结果，程序直接死了。
yuanhuiqiao 2010-04-28
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加个Application.Doevent（）试试
