vb.net - 监视文件中 md5 代码的文件夹监视器仅冻结

Question

编辑：我试图更改代码，例如。而是使用不同的潜艇。但是现在，当某些事情发生变化时，程序只会崩溃。我已经禁用了日志记录、设置断点等，但程序并没有持续多久。这是 Visual Basic 日志中的错误消息（每次程序崩溃时都会出现）：

System.Windows.Forms.dll 中出现“System.InvalidOperationException”类型的第一次机会异常

这是代码（如果您想知道 ExecProtectCompareModule 和 ExecProtect 是什么，我已经进行了一些进程监视器测试）：

Imports System.IO
Imports System.Diagnostics
Imports System.Text
Imports System.Security.Cryptography
Public Class Form1
Dim processList As String
Dim processList2 As String
Public watchfolder As FileSystemWatcher
Dim log As String

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click

    watchfolder = New System.IO.FileSystemWatcher()
    watchfolder.IncludeSubdirectories = True

    watchfolder.Path = TextBox1.Text



    watchfolder.NotifyFilter = IO.NotifyFilters.DirectoryName
    watchfolder.NotifyFilter = watchfolder.NotifyFilter Or _
                               IO.NotifyFilters.FileName
    watchfolder.NotifyFilter = watchfolder.NotifyFilter Or _
                               IO.NotifyFilters.Attributes


    AddHandler watchfolder.Changed, AddressOf logchange
    AddHandler watchfolder.Created, AddressOf logchange
    AddHandler watchfolder.Deleted, AddressOf logchange


    AddHandler watchfolder.Renamed, AddressOf logrename


    watchfolder.EnableRaisingEvents = True

    Button1.Enabled = False
    Button2.Enabled = True


End Sub
Private Sub logchange(ByVal source As Object, ByVal e As  _
                    System.IO.FileSystemEventArgs)
    '  Dim msg As String = Environment.NewLine & "File " & e.FullPath & " "

    ' Select Case e.ChangeType
    '  Case IO.WatcherChangeTypes.Created
    '  msg &= "has been created" + "  " + "Time:" + " " + Format(TimeOfDay)

    '  Case IO.WatcherChangeTypes.Deleted
    ' msg &= "has been deleted" + "  " + "Time:" + " " + Format(TimeOfDay)

    '   Case IO.WatcherChangeTypes.Changed
    ' msg &= "has been modified" + "  " + "Time:" + " " + Format(TimeOfDay)

    '  End Select






    'log &= msg
    'log &= Chr(13)






    'Dim writer As New IO.StreamWriter("log.txt", True)
    'writer.WriteLine(msg)
    'writer.Close()


    Label6.Text = e.FullPath
    md5checkdelay.Start()
End Sub

Public Sub logrename(ByVal source As Object, ByVal e As  _
                        System.IO.RenamedEventArgs)
    Select Case e.ChangeType
        Case IO.WatcherChangeTypes.Created
            Exit Sub
        Case IO.WatcherChangeTypes.Changed
            Exit Sub
        Case IO.WatcherChangeTypes.Deleted
            Exit Sub
        Case Else



            ' Dim msgrn As String = Environment.NewLine & "File " + e.OldName + " "
            ' msgrn &= "has been renamed to" + " " + e.Name + "  " + "Time:" + " " + Format(TimeOfDay)

            ' log &= msgrn
            ' log &= Chr(13)







            'Dim writer As New IO.StreamWriter("log.txt", True)
            'writer.WriteLine(msgrn)
            'writer.Close()

            Label5.Text = e.FullPath
            md5checkdelay.Start()
    End Select
End Sub
Sub md5check()

    Dim md5code As String

    Dim md5 As MD5CryptoServiceProvider = New MD5CryptoServiceProvider
    Dim f As FileStream = New FileStream(Label5.Text, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
    'f = New FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
    md5.ComputeHash(f)
    'Dim ObjFSO As Object = CreateObject("Scripting.FileSystemObject")
    'Dim objFile = ObjFSO.GetFile(e.FullPath)

    Dim hash As Byte() = md5.Hash
    Dim buff As StringBuilder = New StringBuilder
    Dim hashByte As Byte
    For Each hashByte In hash
        buff.Append(String.Format("{0:X1}", hashByte))
    Next
    md5code = buff.ToString()

    If md5code = "D41D8CD98F0B24E980998ECF8427E" Then
        Dim frm2 As New Form2
        frm2.Show()
        f.Close()
    Else
        f.Close()
    End If
End Sub
Sub md5check2()

    Dim md5code As String

    Dim md5 As MD5CryptoServiceProvider = New MD5CryptoServiceProvider
    Dim f As FileStream = New FileStream(Label5.Text, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
    'f = New FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
    md5.ComputeHash(f)
    'Dim ObjFSO As Object = CreateObject("Scripting.FileSystemObject")
    'Dim objFile = ObjFSO.GetFile(e.FullPath)

    Dim hash As Byte() = md5.Hash
    Dim buff As StringBuilder = New StringBuilder
    Dim hashByte As Byte
    For Each hashByte In hash
        buff.Append(String.Format("{0:X1}", hashByte))
    Next
    md5code = buff.ToString()

    If md5code = "D41D8CD98F0B24E980998ECF8427E" Then
        Dim frm2 As New Form2
        frm2.Show()
        f.Close()
    Else
        f.Close()
    End If
End Sub

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click

    watchfolder.EnableRaisingEvents = False
    Button1.Enabled = True
    Button2.Enabled = False
End Sub

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
    Dim frm2 As New Form2
    frm2.ShowDialog()
End Sub

Private Sub ExecProtect_Tick(sender As System.Object, e As System.EventArgs) Handles ExecProtectMonitorModule.Tick
    For Each p As Process In Process.GetProcesses()
        processList = processList & " " & p.ProcessName & vbNewLine
    Next
    Label3.Text = processList
End Sub

Private Sub ExecProtectCompareModule_Tick(sender As System.Object, e As System.EventArgs) Handles ExecProtectCompareModule.Tick
    If Not Label2.Text = Label3.Text Then
        MsgBox("New process started!", 0 + 64)
        processList2refresh()
    End If
End Sub
Sub processList2refresh()
    For Each p As Process In Process.GetProcesses()
        processList2 = processList2 & " " & p.ProcessName & vbNewLine
        Exit Sub
    Next
End Sub

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    For Each p As Process In Process.GetProcesses()
        processList2 = processList2 & " " & p.ProcessName & vbNewLine
    Next
    Label2.Text = processList2
End Sub

Private Sub md5checkdelay_Tick(sender As System.Object, e As System.EventArgs) Handles md5checkdelay.Tick
    'The timer that adds 1 second delay before it checks the md5code after the file(s) is changed
    Label4.Text = Label4.Text + 1
    If Label4.Text = 1 Then
        md5check()
    End If
End Sub

Private Sub md5checkdelay2_Tick(sender As System.Object, e As System.EventArgs) Handles md5checkdelay2.Tick
    'The timer that adds 1 second delay before it checks the md5code after the file(s) is changed but for the rename function instead
    Label7.Text = Label7.Text + 1
    If Label7.Text = 1 Then
        md5check2()
    End If
End Sub

结束类

编辑结束

我之前提出了一个问题，名为“仅监视文件中的 md5 代码的文件夹监视器崩溃”，有人告诉我关闭文件流并使用另一个代码来显示表单。但它不起作用。我制作了一个名为 TestForm 的表单，它不包含任何内容，只包含表单，因为当我尝试显示包含 PictureBoxes 等的 Form2 时整个程序关闭，并且我编写了代码以在 md5 时显示 TestForm修改后的文件的代码和我在代码中指定的md5代码相同，但是显示的表格只显示冻结，文件流不会关闭，我尝试使用 f.Close() 关闭文件流。但是，如果我编写代码以在修改文件的 md5 代码等于我在代码中指定的 md5 代码时显示一个 MsgBox，它就可以正常工作。这是代码：

Imports System.IO
Imports System.Diagnostics
Imports System.Text
Imports System.Security.Cryptography
Public Class Form1
Public watchfolder As FileSystemWatcher

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click

    watchfolder = New System.IO.FileSystemWatcher()
    watchfolder.IncludeSubdirectories = True

    watchfolder.Path = TextBox1.Text



    watchfolder.NotifyFilter = IO.NotifyFilters.DirectoryName
    watchfolder.NotifyFilter = watchfolder.NotifyFilter Or _
                               IO.NotifyFilters.FileName
    watchfolder.NotifyFilter = watchfolder.NotifyFilter Or _
                               IO.NotifyFilters.Attributes


    AddHandler watchfolder.Changed, AddressOf logchange
    AddHandler watchfolder.Created, AddressOf logchange
    AddHandler watchfolder.Deleted, AddressOf logchange


    AddHandler watchfolder.Renamed, AddressOf logrename


    watchfolder.EnableRaisingEvents = True

    Button1.Enabled = False
    Button2.Enabled = True


End Sub
Private Sub logchange(ByVal source As Object, ByVal e As  _
                    System.IO.FileSystemEventArgs)
    If System.IO.Path.GetFileName(e.FullPath).ToLower = "log.txt" Then Exit Sub
    Dim msg As String = Environment.NewLine & "File " & e.FullPath & " "

    Select Case e.ChangeType
        Case IO.WatcherChangeTypes.Created
            msg &= "has been created" + "  " + "Time:" + " " + Format(TimeOfDay)

        Case IO.WatcherChangeTypes.Deleted
            msg &= "has been deleted" + "  " + "Time:" + " " + Format(TimeOfDay)

        Case IO.WatcherChangeTypes.Changed
            msg &= "has been modified" + "  " + "Time:" + " " + Format(TimeOfDay)

    End Select

    Dim writer As New IO.StreamWriter("log.txt", True)
    writer.WriteLine(msg)
    writer.Close()
    Dim md5code As String



    Dim md5 As MD5CryptoServiceProvider = New MD5CryptoServiceProvider
    Dim f As FileStream = New FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
    f = New FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
    md5.ComputeHash(f)
    Dim ObjFSO As Object = CreateObject("Scripting.FileSystemObject")
    Dim objFile = ObjFSO.GetFile(e.FullPath)

    Dim hash As Byte() = md5.Hash
    Dim buff As StringBuilder = New StringBuilder
    Dim hashByte As Byte
    For Each hashByte In hash
        buff.Append(String.Format("{0:X1}", hashByte))
    Next
    md5code = buff.ToString()
    If md5code = "D41D8CD98F0B24E980998ECF8427E" Then 'D41D8CD98F0B24E980998ECF8427E is the md5code of a blank txt file
        ' Dim frm2 As New Form2
        ' frm2.Show()
        TestForm.Show()
        f.Close()
    Else
        f.Close()
    End If
End Sub

Public Sub logrename(ByVal source As Object, ByVal e As  _
                        System.IO.RenamedEventArgs)
    Select Case e.ChangeType
        Case IO.WatcherChangeTypes.Created
            Exit Sub
        Case IO.WatcherChangeTypes.Changed
            Exit Sub
        Case IO.WatcherChangeTypes.Deleted
            Exit Sub
        Case Else
            Dim msgrn As String = Environment.NewLine & "File " + e.OldName + " "
            msgrn &= "has been renamed to" + " " + e.Name + "  " + "Time:" + " " + Format(TimeOfDay)
            Dim writer As New IO.StreamWriter("log.txt", True)
            writer.WriteLine(msgrn)
            writer.Close()
    End Select

End Sub

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click

    watchfolder.EnableRaisingEvents = False
    Button1.Enabled = True
    Button2.Enabled = False
End Sub
End Class

score 0 · Accepted Answer

Dim f As FileStream = New FileStream(e.FullPath, FileMode.Open, _
         FileAccess.Read, FileShare.Read, 8192)
f = New FileStream(e.FullPath, FileMode.Open, FileAccess.Read, _
     FileShare.Read, 8192)
md5.ComputeHash(f)

编辑

注意到有什么奇怪的吗？您正在打开文件上的文件流，然后立即使用相同的变量在同一文件上打开另一个文件流，而不关闭第一个。这就是它报告在 VS 中打开的文件的原因之一。删除该行。f = New FileStream...

当事件因文件删除而触发时，您将在这里遇到另一个问题。

然后：

Dim ObjFSO As Object = CreateObject("Scripting.FileSystemObject")
Dim objFile = ObjFSO.GetFile(e.FullPath)

最后两个似乎没有做任何事情。对象已创建但未使用。但由于objFile是从相关文件构建的，它可能会阻止您删除或使用该文件。

Dim hash As Byte() = md5.Hash
Dim buff As StringBuilder = New StringBuilder
Dim hashByte As Byte
For Each hashByte In hash
    buff.Append(String.Format("{0:X1}", hashByte))
Next
md5code = buff.ToString()

由于您现在有了 MD5 代码，您应该关闭文件流 ( f) 以便您可以做其他事情。您不能在文件打开时删除或移动文件。

If md5code = "D41D8CD98F0B24E980998ECF8427E" Then 
    ' Dim frm2 As New Form2
    ' frm2.Show()
    TestForm.Show()
    f.Close()
Else
    f.Close()
End If

与您之前的代码一样，如果 TestForm 是表单类，则必须创建它的一个实例：

Dim frm As New TestForm
frm.Show                       ' or frm.ShowDialog

表单只是类。您必须在使用它们之前实例化它们。

继续编辑

最后，冻结是在日志事件中执行过多操作的结果（日志更改并计算 MD5 并显示新表单）。您可能已经注意到，在监视许多文件夹中的许多文件时，您的应用程序并没有变慢。那是因为文件观察器在不同的线程上运行。当您创建一个新表单的实例或从该事件中显示它时，该表单显然在该线程上运行。

您需要重新编写代码以删除与实际日志记录无关的内容。在那种情况下，您可以将更改的文件添加到表示待办事项列表的 List(of String) 中，而不是所有这些东西。执行 MD5 并在该列表的其他位置形成内容，以便在您的应用程序线程上进行。

最终编辑

如果您担心的只是表格冻结，请添加以下内容：

    watchfolder = New System.IO.FileSystemWatcher()
    watchfolder.SynchronizingObject = Me

只会耽误更重大的问题，但你似乎认为它很重要。接下来，我已经告诉过你 3 次了，但是如果文件操作是删除，你必须退出日志例程，因为你无法打开已删除的文件：

Case IO.WatcherChangeTypes.Deleted
    Exit Sub                         ' after the log

您将遇到的下一个问题是 2+ 文件已更改。您需要一种对文件/任务进行排队的方法。您为某些东西调用其他潜艇的方法确实将事情分解为离散的任务，但是那些称为 sub 的任务是从 FW 线程调用的，因此您只是将问题转移了。对于一个队列，我在想一个 List(of String)，但是一个带有自己 BackgroundWorker 的新类（如您上一篇文章中所建议的）可能会更好。

Public Class FileMgr
  Friend thisFile As String
  Friend thisHash As String = ""

  Dim frm2 As Form2
  Private WithEvents bw As BackgroundWorker


  Public Sub New(ByVal f As String)
      thisFile = f

      bw = New BackgroundWorker
      AddHandler bw.DoWork, AddressOf ProcessFile
      ' Explorer might not be done creating it yet, 
      ' especially if you drop 3-4 files, so wait
      Threading.Thread.Sleep(250)
      ' start the BW with the name of the file
      bw.RunWorkerAsync(thisFile)
  End Sub

ProcessFile 只是您的（固定）MD5 子，带有新声明：

  Private Sub ProcessFile(ByVal sender As Object, _
       ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bw.DoWork

     Dim sFile As String = e.Argument

再次，一旦你有哈希关闭文件：

    md5.ComputeHash(f)
    f.Close()

不要打开任何表格。只需获取哈希即可。

    For Each hashByte In hash
        buff.Append(String.Format("{0:X1}", hashByte))
    Next

    thisHash = buff.ToString()       ' last line!!!

当 BackgroundWorker 完成时，它会引发一个事件：

Private Sub bw_RunWorkerCompleted(ByVal sender As Object, _
    ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) _
      Handles bw.RunWorkerCompleted

   ' I dont know why each file has to have its own form rather
   ' that a report item in a listbox but I also dont know why you
   ' are computing a hash for a 0 byte new file
    If thisHash = "D41D8CD98F0B24E980998ECF8427E" Then
        frm2 = New Form2
        frm2.Label1.Text = thisFile
        frm2.Show()
    End If

End Sub
End Class

要使用它，请在日志事件中使用一行代码：

  Dim fMgr As New FileMgr(e.FullPath)

Windows 报告的每个文件操作都会创建一个新的文件助手，它将运行自己的 BackgroundWorker。由于您没有做太多事情，因此在处理大于 0 字节的文件之前，一次不会有太多活动。当文件打开和使用时，您还需要在 MD5Sub/ProcessFile 中使用 Try/Catch。

我在监视文件夹中删除了 6 个文件，获得了 Form2 的 6 个副本，没有错误也没有冻结（甚至没有为这一切投票）。

vb.net - 监视文件中 md5 代码的文件夹监视器仅冻结

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