Uploading files to Onedrive using REST API - rest

Question

I am trying to upload a file into OneDrive using its REST API. This is what I am trying to accomplish based on documentation available at OneDrive Rest API:
POST https://apis.live.net/v5.0/me/skydrive/files?access_token=ACCESS_TOKEN
Content-Type: multipart/form-data; boundary=A300x
--A300x
Content-Disposition: form-data; name="file"; filename="HelloWorld.txt"
Content-Type: application/octet-stream
Hello, World!
--A300x--
This is what I have:
Uri destination = new Uri(string.Format("https://apis.live.net/v5.0/{0}/files?", folder.ID));
BackgroundUploader uploader = new BackgroundUploader ();
uploader.SetRequestHeader("Authorization", "Bearer " + account.AccessToken);
uploader.SetRequestHeader("Content-Type", "multipart/form-data; boundary=\"foo_bar_baz\"");
List<BackgroundTransferContentPart> parts = new List<BackgroundTransferContentPart>();
BackgroundTransferContentPart metaDataPart = new BackgroundTransferContentPart();
metaDataPart.SetHeader("Content-Disposition", "form-data; name=\"file\";filename=\""+content.Name+"\"");
parts.Add(metaDataPart);
BackgroundTransferContentPart contentPart = new BackgroundTransferContentPart();
contentPart.SetHeader("Content-Type", content.ContentType);
// content is a StorageFile
contentPart.SetFile(content);
response.UploadOperation = await uploader.CreateUploadAsync(destination, parts, "form-data", "foo_bar_baz");
This line below causes an Access violation error and the Windows Store app crashes:
response.UploadOperation = await uploader.CreateUploadAsync(destination, parts, "form-data", "foo_bar_baz");

Answer 1

You are creating two BackgroundTransferContentPart and only adding the fist to your 'List'.
I think you only need one, something like this:
List<BackgroundTransferContentPart> parts = new List<BackgroundTransferContentPart>();
BackgroundTransferContentPart metaDataPart = new BackgroundTransferContentPart();
metaDataPart.SetHeader("Content-Disposition",
"form-data; name=\"file\";filename=\"" + content.Name + "\"");
metaDataPart.SetHeader("Content-Type", content.ContentType);
metaDataPart.SetFile(content);
parts.Add(metaDataPart);
UPDATE: Ok, the above code fixed the Access Violation issue. Why you are getting a 400 error is a mystery.
But another way to upload a file to OneDrive is using the PUT method:
Uri putUri = new Uri(string.Format("https://apis.live.net/v5.0/{0}/files/{1}",
"folder.a4fb14adbccd1917.A4FB14ADBCCD1917!32089",
content.Name));
BackgroundUploader uploader = new BackgroundUploader();
uploader.SetRequestHeader("Authorization", "Bearer " + accessToken);
uploader.Method = "PUT";
UploadOperation putOperation = uploader.CreateUpload(putUri, content);
await putOperation.StartAsync();
Have you tried PUT?