Question

我正在构建一个VB.NET Google Drive文件浏览器应用程序，原因可能是您不关心。我正在使用谷歌驱动器v2 sdk，我正在尝试使用用户的整个Google Drive目录结构填充树视图控件（不是文件，只是文件夹。）我的代码工作正常，但是，我担心，它对于拥有大量嵌套文件夹的用户，需要几分钟时间。我使用后台工作线程使用委托函数填充树视图。任何人都可以建议一种更有效的方法吗？

从我的代码中调用NewPopulate（）来创建后台工作线程。从这里开始：

Private Sub NewPopulate()
    TreeView1.Nodes.Add(ActiveUser.Email, ActiveUser.Email)
    bwPopulateTree = New BackgroundWorker
    AddHandler bwPopulateTree.DoWork, AddressOf PopulateTreeStart
    AddHandler bwPopulateTree.RunWorkerCompleted, AddressOf PopulateTreeFinished
    bwPopulateTree.RunWorkerAsync()
    cmbActiveUsers.Enabled = False
End Sub

Private Sub PopulateTreeStart()
    Dim children As ChildList = FileManager.GetFoldersInFolder(ActiveUser.DriveService, "root")
    PopulateTreeLoop(ActiveUser.Email, children)
End Sub

Private Sub PopulateTreeFinished()
    lblToolStripStatus.Text = "Directory listing completed."
    SaveTree()
    cmbActiveUsers.Enabled = True
End Sub

Private Sub PopulateTreeLoop(nodeKey As String, ByVal childList As ChildList)
    If Not childList Is Nothing Then
        Dim user As GoogleUser = ActiveUser
        For Each child As ChildReference In childList.Items
            Dim successful As Boolean = False
            If TreeView1.InvokeRequired Then
                successful = TreeView1.Invoke(New m_FindAddNode(AddressOf FindAddNode), {nodeKey, child})
            Else
                successful = FindAddNode(nodeKey, child)
            End If
            Dim children As ChildList = FileManager.GetFoldersInFolder(user.DriveService, child.Id)
            If Not children Is Nothing Then
                PopulateTreeLoop(child.Id, children)
            End If
        Next
    End If
    End Sub

Private Function FindAddNode(nodeKey As String, child As ChildReference) As Boolean
    'Returns true if successful
    Try
        Dim service As DriveService = ActiveUser.DriveService
        Dim file As Drive.v2.Data.File = service.Files.Get(child.Id).Fetch()
        Dim node() As TreeNode = TreeView1.Nodes.Find(nodeKey, True)
        Dim strTitle As String
        If file.FileExtension Is Nothing Then
            strTitle = file.Title
        Else
            strTitle = If(file.Title.EndsWith(file.FileExtension), file.Title, file.Title + file.FileExtension)
        End If
        node(0).Nodes.Add(file.Id, strTitle)
        Return True
    Catch ex As Exception
        Return False
    End Try
End Function

这是我的FileManager类函数：

Public Shared Function GetFoldersInFolder(service As DriveService, ByVal folderId As String) As ChildList
    Dim request As Google.Apis.Drive.v2.ChildrenResource.ListRequest = service.Children.List(folderId)
    request.Q = "mimeType='application/vnd.google-apps.folder'"
    Return request.Fetch()
End Function

抱歉，我必须包含这么多代码，但我试图只包含必要的代码。我也已经有了允许我缓存目录结构的代码，但决定它很难实现，因为我必须检查以确保事情没有改变......我真的只需要更快的检索方式目录结构。我知道另一种方法是让treeview只在用户点击父文件夹时填充子文件夹，但我想避免等待服务器响应每个请求所产生的短暂停顿，每次用户点击新文件夹。

我还有一个检索所有文件夹的功能：

Public Shared Function GetAllFolders(service As DriveService) As FileList
    Dim request As Google.Apis.Drive.v2.FilesResource.ListRequest = service.Files.List
    Dim request2 As Google.Apis.Drive.v2.FilesResource.ListRequest = service.Files.List
    request.Q = "mimeType='application/vnd.google-apps.folder'"
    Return request.Fetch()
End Function

但我无法想出任何有效的方法来解析该列表以提出目录结构......任何想法？我非常感谢你的帮助。我已经做了好几天......

Answer 1

你的方法很合理。很抱歉，使用大型Google Drives需要很长时间。我当然认为只有在用户尝试扩展父节点时才填充子节点，这是正确的想法。预期暂停，但你可以通过向用户显示一些反馈来减轻它，例如Loading...。

在这个云计算时代，用户在从远程服务加载数据时会产生一些延迟。随着网络速度的提高，这将在未来得到改善。

Google Drive SDK - 使用Google Drive目录结构填充.NET TreeView

1 个答案: