Dynamics CRM Attachment Data Import Using SDK - dynamics-crm

Question

I am trying to import Attachments/Annotations to CRM Dynamics, I am doing this using the SDK.
I am not using the data import wizard.
I am not individually creating Annotation entities, instead I am using Data Import Feature programmatically.
I mostly leveraged the DataImport sample from the SDK sample code (SDK\SampleCode\CS\DataManagement\DataImport).
Import import = new Import()
{
ModeCode = new OptionSetValue((int)ImportModeCode.Create),
Name = "Data Import"
};
Guid importId = _serviceProxy.Create(import);
_serviceProxy.Create(
new ColumnMapping()
{
ImportMapId = new EntityReference(ImportMap.EntityLogicalName, importMapId),
ProcessCode = new OptionSetValue((int)ColumnMappingProcessCode.Process),
SourceEntityName = sourceEntityName,
SourceAttributeName = sourceAttributeName,
TargetEntityName = targetEntityName,
TargetAttributeName = targetAttributeName
});
I am getting an error "The reference to the attachment could not be found".
The documentation says the crm async service will find the physical file on disk and upload it, my question is where does the async service look for attachment files?
I tried to map documentbody field to the full path of the attachment on the desk, but that still didn't work.

Answer 1

The answer below was provided before the question edits clarifying the use of the import wizard instead of the SDK. The answer below is specific to using the SDK.
When you are attaching files to an Annotation (Note) record in CRM via the SDK, you do use the documentbody attribute (along with mimetype), but you have to first convert it base64.
Something like this:
var myFile = #"C:\Path\To\My\File.pdf";
// Do checks to make sure file exists...
// Convert to Base64.
var base64Data = Convert.ToBase64String(System.IO.File.ReadAllBytes(myFile));
var newNote = new Entity("annotation");
// Set subject, regarding object, etc.
// Add the data required for a file attachment.
newNote.Attributes.Add("documentbody", base64Data);
newNote.Attributes.Add("mimetype", "text/plain"); // This mime type seems to work for all file types.
orgService.Create(newNote);

Answer 2

I found the solution in an obscure blog post, I think the documentation is misleading or unclear, the way this whole thing works, makes having the files available on the server disk for the async to process, odd.
To follow the same principle, all contents should be sent like the csv file itself while being linked to the same import.
To solve this we need create individual special Internal ImportFile for each physical attachment, and link it to the import that has the attachments record details.
As you see below with linking the attachments ImportFile using the ImportId and then setting the two properties (ProcessCode and FileTypeCode), it all worked in the end.
Suffice to say using this method is much more efficient and quicker than individually creating Annotation records.
foreach (var line in File.ReadLines(csvFilesPath + "Attachment.csv").Skip(1))
{
var fileName = line.Split(',')[0].Replace("\"", null);
using (FileStream stream = File.OpenRead(attachmentsPath + fileName))
{
byte[] byteData = new byte[stream.Length];
stream.Read(byteData, 0, byteData.Length);
stream.Close();
string encodedAttachmentData = System.Convert.ToBase64String(byteData);
ImportFile importFileAttachment = new ImportFile()
{
Content = encodedAttachmentData,
Name = fileName,
ImportMapId = new EntityReference(ImportMap.EntityLogicalName, importMapId),
UseSystemMap = true,
ImportId = new EntityReference(Import.EntityLogicalName, importId),
ProcessCode = new OptionSetValue((int)ImportFileProcessCode.Internal),
FileTypeCode = new OptionSetValue((int)ImportFileFileTypeCode.Attachment),
RecordsOwnerId = currentUserRef
};
_serviceProxy.Create(importFileAttachment);
}
idx++;
}