Vb.net 文件正在使用中

Question

IT 说文件正在使用中 我不知道为什么

错误：

System.IO.IOException was unhandled   Message=The process cannot access the file 'C:\Users\Bradley Smithies\AppData\Roaming\.minecraft\screenshots\2011-07-11_09.34.15.png' because it is being used by another process.   Source=mscorlib   StackTrace:
       at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
       at System.IO.File.Delete(String path)
       at ScreenShotCraft.frmindex.btndeleteselected_Click(Object sender, EventArgs e) in D:\Coding\Visual Basic\ScreenshotCraft\frmindex.vb:line 107
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at ScreenShotCraft.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()   InnerException:

代码：

Imports System.Environment

Public Class frmindex
    Dim output As String
    Dim appdata As String = GetFolderPath(SpecialFolder.ApplicationData)
    Dim path As String = appdata + "\.minecraft\screenshots"
    Private Sub frmindex_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        If Not System.IO.Directory.Exists(appdata + "\.minecraft\screenshots") = True Then
            ' Creates a FolderBrowserDialog object
            Dim fbdpath As New FolderBrowserDialog
            'Dialog
            With fbdpath
                ' Desktop is the path folder in the dialog.
                ' Select the C:\Windows directory on entry.
                .SelectedPath = CurDir()
                ' Prompt the user with a custom message.
                .Description = "Please Select Your Minecraft Screenshot Folder"
                path = .SelectedPath
                If .ShowDialog = DialogResult.OK Then
                    path = .SelectedPath
                End If
            End With
        End If

        Dim strBasePath As String = path
        Dim dirInputFileInfo As IO.FileInfo
        Dim dirInputInfo As New IO.DirectoryInfo(strBasePath)
        Dim dirInputFileArray As IO.FileInfo() = dirInputInfo.GetFiles()

        For Each dirInputFileInfo In dirInputFileArray
            Me.clbfiles.Items.Add(dirInputFileInfo.Name)
        Next
    End Sub

    Private Sub btnbrowse_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnbrowse.Click
        ' Creates a FolderBrowserDialog object
        Dim fbdoutput As New FolderBrowserDialog
        'Dialog
        With fbdoutput
            ' Desktop is the root folder in the dialog.
            .RootFolder = Environment.SpecialFolder.Desktop
            ' Select the C:\Windows directory on entry.
            .SelectedPath = CurDir()
            ' Prompt the user with a custom message.
            .Description = "Please select where you would like the pictures to be places"
            output = .SelectedPath
            If .ShowDialog = DialogResult.OK Then
                output = .SelectedPath
                txboutput.Text = output
            End If
        End With
    End Sub



    Private Sub clbfiles_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles clbfiles.SelectedIndexChanged
        If Not clbfiles.SelectedItem = "" Then
            pcbpreview.Image = Image.FromFile(path + "\" + clbfiles.SelectedItem.ToString)
        End If
    End Sub

    Private Sub btnselectall_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnselectall.Click
        For i As Integer = 0 To Me.clbfiles.Items.Count - 1
            Me.clbfiles.SetItemChecked(i, True)
        Next i
    End Sub

    Private Sub btnunselectall_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnunselectall.Click
        For i As Integer = 0 To Me.clbfiles.Items.Count - 1
            Me.clbfiles.SetItemChecked(i, False)
        Next i
    End Sub
    Private Sub btndeleteall_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btndeleteall.Click
        For i As Integer = 0 To Me.clbfiles.Items.Count - 1
            Me.clbfiles.SetItemChecked(i, True)
        Next i
        Dim CheckedItems(clbfiles.CheckedItems.Count - 1) As Object
        clbfiles.CheckedItems.CopyTo(CheckedItems, 0)
        For Each CheckedItem As Object In CheckedItems
            Dim FileToDelete As String
            'creates path to delete
            FileToDelete = appdata + "\" + CheckedItem.ToString

            If System.IO.File.Exists(FileToDelete) = True Then
                'deletes
                System.IO.File.Delete(FileToDelete)
                MsgBox("File Deleted")

            End If
            'removes from list
            clbfiles.Items.Remove(CheckedItem)

        Next
    End Sub

    Private Sub btndeleteselected_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btndeleteselected.Click
        Dim CheckedItems(clbfiles.CheckedItems.Count - 1) As Object
        clbfiles.CheckedItems.CopyTo(CheckedItems, 0)
        For Each CheckedItem As Object In CheckedItems
            Dim FileToDelete As String
            'creates path to delete
            FileToDelete = path + "\" + CheckedItem.ToString

            If System.IO.File.Exists(FileToDelete) = True Then
                'deletes
                System.IO.File.Delete(FileToDelete)<-----------ERROR HERE, say file in use
                MsgBox("File Deleted")

            End If
            'removes from list
            clbfiles.Items.Remove(CheckedItem)

        Next
    End Sub

    Private Sub btncopy_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btncopy.Click
        Dim CheckedItems(clbfiles.CheckedItems.Count - 1) As Object
        clbfiles.CheckedItems.CopyTo(CheckedItems, 0)
        For Each CheckedItem As Object In CheckedItems
            Dim FileToDelete As String
            'creates path to delete
            FileToDelete = path + "\" + CheckedItem.ToString

            If System.IO.File.Exists(FileToDelete) = True Then
                If System.IO.File.Exists(output + "\" + CheckedItem.ToString) = False Then
                    'deletes
                    System.IO.File.Copy(FileToDelete, output + "\" + CheckedItem.ToString)
                    MsgBox("Files Copied")

                End If
            End If
            'removes from list

        Next
    End Sub

    Private Sub btnmove_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnmove.Click
        Dim CheckedItems(clbfiles.CheckedItems.Count - 1) As Object
        clbfiles.CheckedItems.CopyTo(CheckedItems, 0)
        For Each CheckedItem As Object In CheckedItems
            Dim FileToDelete As String
            'creates path to delete
            FileToDelete = path + "\" + CheckedItem.ToString

            If System.IO.File.Exists(FileToDelete) = True Then
                'deletes
                System.IO.File.Move(FileToDelete, output + "\" + CheckedItem.ToString)
                MsgBox("Files Moved")

            End If
            'removes from list
            clbfiles.Items.Remove(CheckedItem)

        Next
    End Sub
End Class

Answer 1

我认为您需要对图像预览做一些事情-您需要处理使用FromFile加载的 Image 实例：

该文件保持锁定状态，直到图像被释放。

您可能想要执行以下操作：

Private Sub clbfiles_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles clbfiles.SelectedIndexChanged
    Dim prevImage = pcbpreview.Image
    pcbreview.Image = Nothing
    If Not prevImage Is Nothing then
        prevImage.Dispose()
    End If
    If Not clbfiles.SelectedItem = "" Then
        pcbpreview.Image = Image.FromFile(path + "\" + clbfiles.SelectedItem.ToString)
    End If
End Sub

和一个类似的抓取图像实例/设置预览为空/在执行删除操作之前处理上一个图像。