Question

如何检查String值是文件夹还是文件？我使用FileSystemWatcher检查文件或文件夹中的更改，然后将其存储在List(Of String)中并使用以下代码：

Private Sub logrename(ByVal source As Object, ByVal e As System.IO.RenamedEventArgs)
    oldfldrnme.Add(e.OldName)
    newfldrnme.Add(e.Name)
End Sub

使用此代码：

Dim dest As String = Label6.Text

    For i = 0 To oldfldrnme.Count - 1 And newfldrnme.Count - 1
        Dim attri As FileAttribute = File.GetAttributes(i)
        If ((attri And FileAttribute.Directory) = FileAttribute.Directory) Then
            Microsoft.VisualBasic.FileIO.FileSystem.RenameDirectory(dest & "\" & oldfldrnme(i), newfldrnme(i))
        Else
            Microsoft.VisualBasic.FileIO.FileSystem.RenameFile(dest & "\" & oldfldrnme(i), newfldrnme(i))
        End If
    Next

FileNotFound Exception引发此行Visual Studio 2010\Projects\File Sync2\File Sync\bin\Debug\0'.

但使用此代码：

For i = 0 To oldfldrnme.Count - 1 And newfldrnme.Count - 1
        Dim ex As String = Path.HasExtension(i)
        If ex = False Then
            Microsoft.VisualBasic.FileIO.FileSystem.RenameDirectory(dest & "\" & oldfldrnme(i), newfldrnme(i))
        Else
            Microsoft.VisualBasic.FileIO.FileSystem.RenameFile(dest & "\" & oldfldrnme(i), newfldrnme(i))
        End If
    Next

使用目录，但是使用文件告诉它它是一个目录，使DirectoryNotFoundException

投掷Could not find directory 'D:\Test2\New Text Document.txt'.

Answer 1

首先，您无法在For Next语句中使用Path.HasExtension()。这会导致您按位组合两个整数。

其次，文件可能没有扩展名，因此检查IO.Path.Combine()可能会在某个时刻引发异常。

第三，要将路径连接在一起，最好使用Math.Min()。

首先我们处理按位组合语句。使用IndexOutOfRangeException，您将获得两个值中最低的值（您必须这样做，因为如果由于某种原因，某个项目的项目数多于另一个，则代码将抛出For i = 0 To Math.Min(oldfldrnme.Count, newfldrnme.Count) - 1）。

Directory.Exists(i)

现在让我们检查路径是否是文件。您无法执行i因为Directory.Exists(<path to be renamed>)是您的Integer变量，而不是完整路径。要正确检查，您必须IO.Path.Combine()。我们使用For i = 0 To Math.Min(oldfldrnme.Count, newfldrnme.Count) - 1 Dim DestPath As String = Path.Combine(dest, oldfldrnme(i)) 'This is the file/directory to be renamed. If File.Exists(DestPath) Then ElseIf Directory.Exists(DestPath) Then End If Next来正确获取目标路径。

For i = 0 To Math.Min(oldfldrnme.Count, newfldrnme.Count) - 1
    Dim DestPath As String = Path.Combine(dest, oldfldrnme(i)) 'This is the file/directory to be renamed.
    If File.Exists(DestPath) Then
        Microsoft.VisualBasic.FileIO.FileSystem.RenameFile(DestPath, newfldrnme(i))
    ElseIf Directory.Exists(DestPath) Then
        Microsoft.VisualBasic.FileIO.FileSystem.RenameDirectory(DestPath, newfldrnme(i))
    End If
Next

最后，我们进行重命名。

Try Catch

修改

正如Cody Gray指出的那样，如果其他事情对您的文件/目录执行I / O操作，您应该在代码中添加一些异常处理。

因此我们将围绕重命名操作添加Catch语句。如果发生错误，将执行For i = 0 To Math.Min(oldfldrnme.Count, newfldrnme.Count) - 1 Dim DestPath As String = Path.Combine(dest, oldfldrnme(i)) 'This is the file/directory to be renamed. If File.Exists(DestPath) Then Try Microsoft.VisualBasic.FileIO.FileSystem.RenameFile(DestPath, newfldrnme(i)) Catch ex As Exception 'Log error using ex.Message. For example "Could not rename file: " & ex.Message End Try ElseIf Directory.Exists(DestPath) Then Try Microsoft.VisualBasic.FileIO.FileSystem.RenameDirectory(DestPath, newfldrnme(i)) Catch ex As Exception 'Log error using ex.Message. For example "Could not rename folder: " & ex.Message End Try End If Next块，这意味着您没有停止整个应用程序的问题。

productDatePickerDialog = new DatePickerDialog(getActivity(), new DatePickerDialog.OnDateSetListener() { public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) { Calendar newDate = Calendar.getInstance(); newDate.set(year, monthOfYear, dayOfMonth); Log.v("Date", "date " + dateFormatter.format(newDate.getTime())); updateDate(dateFormatter.format(newDate.getTime())); }}, newCalendar.get(Calendar.YEAR), newCalendar.get(Calendar.MONTH), newCalendar.get(Calendar.DAY_OF_MONTH)); holder.edt_Three.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { productDatePickerDialog.show(); } }); private void updateDate(String dDate) { Log.v("Date", "date " + dDate); //TODO holder.edt_Three.setText(dDate); notifyDataSetChanged(); }

Answer 2

如果对不存在的项进行调用，GetAttributes函数将抛出异常。怎么可能不这样呢？不存在的东西没有属性。因此，它不是检查某些东西是否存在的一般解决方案。

您需要使用Exists方法。例如：

Public Enum FileSystemObject
    InvalidPath
    Directory
    File
End Enum

Public Function WhatIsThisThing(String path) As FileSystemObject
    If Directory.Exists(path) Then
        Return FileSystemObject.Directory
    Else If File.Exists(path)
        Return FileSystemObject.File
    Else
        Return FileSystemObject.InvalidPath
    End If
End Function

但是，您仍然可以在此处执行竞争条件，就像执行文件I / O时一样。事先执行检查很好，但是还需要处理在尝试重命名对象时可能引发的异常。您无法确保在检查文件或文件夹的时间与发出重命名命令的时间之间没有删除或重命名文件或文件夹。

Answer 3

用于检查VB.NET中存在的路径/文件，

If File.Exists(strPath) Then
    ' yes this is a file
Else
    ' oh no
End If

Answer 4

你可以试试这个：

Imports System.IO

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        ListBox1.Items.Clear()
        Listfolders(TextBox1.Text) 'Call Public Sub ListFolders
    End Sub

    Public Sub Listfolders(ByVal Path As String) 'Path is Texbox1.Text
        Dim DirInfo As New IO.DirectoryInfo(Path) 'C:\!Testfolder
        Dim FileObject As IO.FileSystemInfo
        For Each FileObject In DirInfo.GetFileSystemInfos 'fileobject is file or folder
            If FileObject.Attributes = IO.FileAttributes.Directory Then
                'Fileobject is Folder
                Listfolders(FileObject.FullName) 'Use public Sub again to find folders and files in subfolders                
                ListBox1.Items.Add(FileObject.Name) 'Add folder to listbox
            Else
                'Fileobject is file
                ListBox1.Items.Add(FileObject.Name) 'Add file to listbox
            End If
        Next
    End Sub
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        TextBox1.Text = "C:\!TestFolder" 'Give initial text to Textbox1
    End Sub
End Class

检查String是文件还是文件夹VB.NET

4 个答案: