hello, I have written an app with which you can upload all kinds of files into a dropbox folder. I have already spent several hours trying to fix the error on my own, but I can not find a solution. Whenever I try to upload a file larger than about 30MB, the error message "incorrect_offset" appears.
Imports System.IO
Imports System.Net
Imports Dropbox.Api
Imports Dropbox.Api.Files
Public Class Form1
'Global variable for the Access-Token
Dim client As DropboxClient = New DropboxClient("YOUR TOKEN")
'Global variable to set the Dropbox Folderpath
Dim remotepath As String = "/UploadVideoToDB"
'This is the path for your desired file
Dim path As String = ""
'This variable saves only the file name
Dim filename As String = ""
'This function is not called until the button 'btn_choose_file_click' is clicked
Private Sub btn_choose_file_click(sender As Object, e As EventArgs) Handles btn_choose_file.Click
'This part is there to select a file with the help of the openfiledialog
'This is the start folder that will be displayed when the openfiledialog opens
OpenFileDialog1.InitialDirectory = "C:\"
'Setting up the Title of the openfiledialog window
OpenFileDialog1.FileName = "Open A File..."
'That means you can only select one file (please dont change to 'true')
OpenFileDialog1.Multiselect = False
'This defines which files may be selected
OpenFileDialog1.Filter = "All Files|*.*"
'A little if-query that checks if the openfiledialog returns 'ok' as result.
'If so, then the text Of lbl_filename Is changed To the name Of the selected file.
'In addition, the variable 'path' is assigned the path of the selected file as the value and the variable 'filename' the name.
If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
lbl_filename.Text = OpenFileDialog1.FileName
path = OpenFileDialog1.FileName
filename = System.IO.Path.GetFileName(OpenFileDialog1.FileName)
End If
End Sub
'This function is not called until the button 'btn_upload_click' is clicked
Private Sub btn_upload_Click(sender As Object, e As EventArgs) Handles btn_upload.Click
'These lines deactivate the two buttons (so that they can not be clicked repeatedly)
'And call the function 'Upload' with the parameters 'remotepath & filename'
btn_choose_file.Enabled = False
btn_upload.Enabled = False
Upload(remotepath & "/" & filename)
End Sub
'remotepath = remotepath & "/" & filename
Private Async Sub Upload(remotePath As String)
'This line determines how big the individual packages sent should be. this value may not exceed 150MB. (PLease dont change this value)
Const ChunkSize As Integer = 8024 * 1024
'This filestream reads the file under the given path in 'path'
Using localfile As FileStream = New FileStream(path, FileMode.Open, FileAccess.Read)
'Checks if the selected file is bigger then the determined ChunkSize
If localfile.Length <= ChunkSize Then
Try
'Gives the cursor a little loading animation so the user can see that something happens
Cursor = Cursors.WaitCursor
'Uploads the selected file to the Dropbox folder
Await client.Files.UploadAsync(remotePath, body:=localfile)
'Resets the cursor to default
Cursor = Cursors.Default
MessageBox.Show("Successfully Uploaded!")
'Enables both buttons
btn_choose_file.Enabled = True
btn_upload.Enabled = True
'If an error has occurred, it will be displayed in a messagebox
Catch ex As Exception
MessageBox.Show(ex.Message)
btn_choose_file.Enabled = True
btn_upload.Enabled = True
Cursor = Cursors.Default
End Try
Else
Try
'if the file is larger than the variable 'ChunkSize' the function 'ChunkUpload' is called
Await ChunkUpload(remotePath, filename, ChunkSize)
'If an error has occurred, it will be displayed in a messagebox
Catch ex As Exception
MessageBox.Show(ex.Message)
btn_choose_file.Enabled = True
btn_upload.Enabled = True
Cursor = Cursors.Default
End Try
End If
End Using
End Sub
'folder = remotepath
'fileName = filename
'chunksize = ChunkSize
Private Async Function ChunkUpload(folder As String, fileName As String, chunksize As Integer) As Task
'This filestream reads the file under the given path in 'path'
Dim stream = New FileStream(path, FileMode.Open, FileAccess.Read)
'This function splits the size of the selected file into equal chuck packages and returns the value as an integer
Dim numChunks As Integer = CInt(Math.Ceiling(CDbl(stream.Length) / chunksize))
'The variable 'chunksize' is stored as byte
Dim buffer As Byte() = New Byte(chunksize) {}
Dim sessionId As String = Nothing
Cursor = Cursors.WaitCursor
'This for loop runs until all packages have been transferred
For idx = 0 To numChunks Step 1
Dim byteRead = stream.Read(buffer, 0, chunksize)
Using memStream As MemoryStream = New MemoryStream(buffer, 0, byteRead)
If idx = 0 Then
'If the counter 'idx' has the value 0, then the upload is started
Dim result = Await client.Files.UploadSessionStartAsync(body:=memStream)
'The variable 'sessionid' stores the ID for this upload process. Each upload process has its individual ID
sessionId = result.SessionId
Else
'Unfortunately, I can not write anything about this line. I'm not sure what it is there for. I am sorry!
Dim cursor As UploadSessionCursor = New UploadSessionCursor(sessionId, chunksize)
If idx = numChunks - 1 Then
'when 'idx' reaches the value of 'numchunks', the upload process is completed. The file is now created in the DropBox account and all packages are put together.
Await client.Files.UploadSessionFinishAsync(cursor, New CommitInfo(folder & "/" & fileName), memStream)
Else
'More packages will be uploaded
Await client.Files.UploadSessionAppendV2Async(cursor, False, body:=memStream)
End If
End If
End Using
Next
'Resets the cursor to default
Cursor = Cursors.Default
MessageBox.Show("Successfully uploaded!")
'Enables both buttons
btn_choose_file.Enabled = True
btn_upload.Enabled = True
End Function
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'When starting the app, 'Form1' will be displayed in the center of the screen
Me.CenterToScreen()
End Sub
End Class
