Using FileSavePicker to Store 3MF Files

I thought I’d add my solution to my problem here although the point of the question becomes moot.  As a relative nube on WiseJ, an alternative solution resulted from realizing that I’m using WebSocket.  The technique to download I was working on relied on HttpRequest which is incompatible when using WebSocket.  The solution was to skip providing a FileSavePicker and simplify the process using the Application Download(stream,”FileName.3mf”) method.  The stream resulting from the 3D Printing UWP code running in the sub-domain returns a zip file.  I simply downloaded it into the Downloads folder on my PC.  It works great.  I’m still not sure how to implement the FileSavePicker in a sub-domain.  My attempt at using Invoke to call the FileSavePicker process also failed to generate a window handle, but it became unnecessary.

Thanks for the assistance.

Gerry

That is for a desktop app and uses the process MainWindowHandle.

Wisej doesn’t have a UI thread and doesn’t have a main window handle because it’s not a desktop app. You would be opening a file explorer on a web server!

If you are using the Wisej.Application exe  for a standalone app you have to invoke the call on the main UI thread.

Thanks for your reply!  I thought I added the handle using the technique from this article: https://stackoverflow.com/questions/57161258/invalid-window-handle-error-when-using-fileopenpicker-from-c-sharp-net-framwo.  My vb code is below. I’ve been reading through the variety of related topics but this keeps coming up as the accepted approach.  Is there another resource you can point me toward?  Thanks again!

Code:

<ComImport>
<Guid(“3E68D4BD-7135-4D10-8018-9FB6D9F33FA1”)>
<InterfaceType(ComInterfaceType.InterfaceIsIUnknown)>
Interface IInitializeWithWindow
Sub Initialize(ByVal hwnd As IntPtr)
End Interface
Private Async Function SaveTo3mf(localPackage As Printing3D3MFPackage) As Task(Of Boolean)
Dim savePicker As FileSavePicker = New FileSavePicker()
savePicker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary
savePicker.DefaultFileExtension = “.3mf”
savePicker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary
savePicker.FileTypeChoices.Add(“3MF File”, {“.3mf”})

Call CType(CObj(savePicker), IInitializeWithWindow).Initialize(Process.GetCurrentProcess().MainWindowHandle)

Dim storageFile = Await savePicker.PickSaveFileAsync()

If storageFile Is Nothing Then
Return False
End If

Using stream = Await localPackage.SaveAsync()
stream.Seek(0)

Using dataReader = New DataReader(stream)
Await dataReader.LoadAsync(CUInt(stream.Size))
Dim buffer = dataReader.ReadBuffer(CUInt(stream.Size))
Await FileIO.WriteBufferAsync(storageFile, buffer)
End Using
End Using

Return True
End Function

Here is the test 3MFTest project.  I had also built a non-WiseJ Forms App and the code works there.

The discussion where is shows the AppDomain switching approach is here: https://stackoverflow.com/questions/40613882/uwp-api-in-asp-net

The discussion where it shows the possible solution to the Handle problem is here: https://stackoverflow.com/questions/57161258/invalid-window-handle-error-when-using-fileopenpicker-from-c-sharp-net-framwo

Thanks very much!

Gerry

Hi Gerald,

Can you please wrap up a small sample that reproduces the issue ?

Best,

Alaa