how to attach a pdf to a record using code

Local to the server or local to the user?

I could be wrong, but I don’t believe code running server side will be able to accomplish this. Aside from possibly using JavaScript (I cannot confirm this), I don’t think you will be able to accomplish this without having the user choose a file.

That’s not to say you can’t go about it in a different way than what you’ve snipped above. Just that you’ll need to do something similar. I have a feeling this is not what you were hoping though.

I have the following code:

namespace PX.Objects.SO
{
    public class SOShipmentEntry_Extension : PXGraphExtension<SOShipmentEntry>
    {
        #region Event Handlers

        public PXAction<PX.Objects.SO.SOShipment> ApiTracking;

        [PXButton(CommitChanges = true)]
        [PXUIField(DisplayName = "Tracking")]
        protected void apiTracking()
        {
            PXTrace.WriteWarning("PROCESSING 1");

            // Create a BQL command to select SO shipments
            BqlCommand command = new Select<SOShipment>();

            // Create a view for querying SO shipments
            PXView shipmentView = new PXView(Base, true, command);

            // Create a PXAdapter adapter with the shipments view
            PXAdapter adapter = new PXAdapter(shipmentView);

            foreach (SOShipment shipment in adapter.Get<SOShipment>())
            {
                PXTrace.WriteWarning("PROCESSING 2");

                // Get the path of the pre-existing PDF file
                string filePath = @"C:\Path\To\DownloadedFiles\downloadedFile4.pdf";

                // Check if the file exists at the specified path
                if (File.Exists(filePath))
                {
                    PXTrace.WriteWarning("PROCESSING 3");

                    // Create a FileInfo object for the PDF file
                    PX.SM.FileInfo file = new PX.SM.FileInfo(filePath, null, File.ReadAllBytes(filePath));

                    // Check that the objects are not null before calling AttachFile
                    if (Base.Caches[typeof(SOShipment)] != null && shipment != null && file != null)
                    {
                        try
                        {
                            PXTrace.WriteWarning("PROCESSING 4");

                            // Attach the PDF file to the current shipment
                            PXNoteAttribute.AttachFile(Base.Caches[typeof(SOShipment)], shipment, file);

                            PXTrace.WriteWarning("PROCESSING 5");
                        }
                        catch (Exception ex)
                        {
                            // Handle any exception that occurs during AttachFile
                            PXTrace.WriteError($"Error attaching PDF file: {ex.Message}");
                        }
                    }
                    else
                    {
                        // Handle the case where any object is null
                        PXTrace.WriteWarning("Error: One of the required objects is null.");
                    }
                }
                else
                {
                    // Handle the case where the file is not found at the specified path
                    PXTrace.WriteWarning($"PDF file not found at path: {filePath}");
                }
            }
        }
    }
}

but I get an error in this part of the code
  // Attach the PDF file to the current shipment PXNoteAttribute.AttachFile(Base.Caches[typeof(SOShipment)], shipment, file);

The messages shown reach PROCESSING 4 and then show the error
the mistake is :
Error attaching PDF file: Nullable object must have a value.

@vardan22 - But the whole point here is that he's writing server side code attempting to access a file client side. I don't see how that's going to work. I don't think the file will ever be found.