Question

我正在尝试将文本文件保存在此路径中：“C：\ Test \ test.txt”，当文件已经打开时，我需要检查文件是否已打开，我需要在写入之前将其关闭到文件。

以下是保存文件的代码： Dim myfile As String =“C：\ Test \ test.txt”

    'Check if file exists
    If System.IO.File.Exists(myfile) = True Then
        'Delete it!

        Dim fi As New FileInfo(myfile)
        fi.Delete()
    End If



    Using sfdlg As New Windows.Forms.SaveFileDialog
        sfdlg.DefaultExt = "amk"
        sfdlg.Filter = "AquaMark Project|*.amk"
        If sfdlg.ShowDialog = Windows.Forms.DialogResult.OK Then


            Dim SaveData As New gCanvasData


            IO.Directory.CreateDirectory("C:\Test")
            Dim w As New IO.StreamWriter("C:\Test\test.txt")
            Dim i As Integer


            For i = 0 To CheckedListBox1.Items.Count - 1
                w.WriteLine(CheckedListBox1.Items.Item(i))
            Next
            w.Close()
            With SaveData
                frmDisplay.GCanvas1.UnselectCurrentAnotate()
                .gAnnotates = frmDisplay.GCanvas1.gAnnotates
                .Image = frmDisplay.GCanvas1.Image
            End With

            Using objStreamWriter As New StreamWriter(sfdlg.FileName)
                Dim x As New XmlSerializer(GetType(gCanvasData))
                x.Serialize(objStreamWriter, SaveData)
                objStreamWriter.Close()
            End Using
        End If
    End Using

如果我这样做，我可以关闭记事本进程，但我需要关闭特定的打开文本文件：

Dim Process() As Process = System.Diagnostics.Process.GetProcessesByName("notepad")
Process() = CType(Interaction.GetObject("C:\Test\test.txt"), Diagnostics.Process())
For Each p As Process In Process
    p.Kill()
Next

Answer 1

我不相信有一个属性可以让你检查流读取器是否打开。

最佳做法似乎是.close读者完成后。（全部采用的方法。）

如果你还有一个例外，你可以尝试try block来处理异常。

可以在此处找到其他信息和一些示例代码。祝你好运。

MSDN! StreamReader

编辑：您可以使用此功能进行检查。 IO.File

Private Function CheckFile(ByVal filename As String) As Boolean

    Try
        System.IO.File.Open(filename, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.None)
        FileClose(1)
        Return False
    Catch ex As Exception
        Return True
    End Try

End Function

Answer 2

怎么样：

If File.Exists("File1.txt") = False Then
            File.CreateText("File1.txt").Close()
        Else
            Exit Sub
        End If

        If File.Exists("File2.txt") = False Then
            File.CreateText("File2.txt").Close()
        Else
            Exit Sub
        End If
End If

Answer 3

Private Sub IsFileOpen(ByVal file As FileInfo)
    Dim stream As FileStream = Nothing
    Try
        stream = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None)
    Catch ex As IOException 

        If IsFileLocked(ex) Then
          'do something here, either wait a few seconds, close the file if you have  
          'a handle, make a copy of it, read it as shared (FileAccess fileAccess = FileAccess.Read, FileShare fileShare = FileShare.ReadWrite). 
          'I dont recommend terminating the process - which could cause corruption and lose data
        End If
    Catch ex As Exception

    End Try
End Sub

Private Shared Function IsFileLocked(exception As Exception) As Boolean
    Dim errorCode As Integer = Marshal.GetHRForException(exception) And ((1 << 16) - 1)
    Return errorCode = 32 OrElse errorCode = 33
End Function

Answer 4

我的程序附加到电子邮件中的.csv文件出现此问题。我添加了代码以清除MailMessage对象中的Attachments集合，然后在发送邮件后处理MailMessage和Attachment对象。这似乎解决了这个问题。

如何检查文本文件是否打开并关闭文本文件？

4 个答案: