You may want to introduce a processing screen to select the files of interest and then act on those files.

I once used the following code to extract files from the database and dump to a folder on the server.  You would need to modify for your purposes, but it gives some insight into how to get files.

#region ExportAttachments
public static void ExportAttachments(Guid? fromNoteID, string outFolder)
{
	UploadFileMaintenance upload = PXGraph.CreateInstance<UploadFileMaintenance>();

	PXResultset<NoteDoc> list = GetFiles(fromNoteID);
	foreach (NoteDoc doc in list)
	{
		PX.SM.FileInfo sourceFile = upload.GetFile((Guid)doc.FileID);

		if (!Directory.Exists(outFolder)) Directory.CreateDirectory(outFolder);

		string pathOfFile = Path.GetDirectoryName(outFolder) + "\\" + sourceFile.Name;
		File.WriteAllBytes(pathOfFile, sourceFile.BinData);
		PXTrace.WriteInformation(pathOfFile);
	}
}
#endregion

#region GetFiles
public PXResultset<NoteDoc> GetFiles(Guid? noteID)
{
	var list = SelectFrom<NoteDoc>
		.Where<NoteDoc.noteID.IsEqual<@P.AsGuid>>
		.View.Select(this, noteID);
	return list;
}
#endregion

Notice how files are linked to objects such as items throuhg NoteDoc.  From NoteDoc, you get the file via GetFile in the UploadFileMaintenance graph by FileID stored in a PX.SM.FileInfo object.  From that object, the actual file data is contained within the BinData field.

@Brian Stevens Thanks for the insight.

It seems the ExportAttachments doesn’t like the GetFile non-static method and if I make the GetFile static am not able to pass the Base graph to select statement. Was there a trick to make this work?

Also, don’t you possibly have the processing screen code handy so that I modify it instead of rewriting it?

I extracted the code for GetFiles from the graph I had it in.  It was intended to be code samples, so you’d need to tweak it.

Try this.  I simply added a parameter to pass a graph and adjusted accordingly.

#region ExportAttachments
public static void ExportAttachments(Guid? fromNoteID, string outFolder)
{
	UploadFileMaintenance upload = PXGraph.CreateInstance<UploadFileMaintenance>();

	PXResultset<NoteDoc> list = GetFiles(upload, fromNoteID);
	foreach (NoteDoc doc in list)
	{
		PX.SM.FileInfo sourceFile = upload.GetFile((Guid)doc.FileID);

		if (!Directory.Exists(outFolder)) Directory.CreateDirectory(outFolder);

		string pathOfFile = Path.GetDirectoryName(outFolder) + "\\" + sourceFile.Name;
		File.WriteAllBytes(pathOfFile, sourceFile.BinData);
		PXTrace.WriteInformation(pathOfFile);
	}
}
#endregion

#region GetFiles
public static PXResultset<NoteDoc> GetFiles(PXGraph graph, Guid? noteID)
{
	var list = SelectFrom<NoteDoc>
		.Where<NoteDoc.noteID.IsEqual<@P.AsGuid>>
		.View.Select(graph, noteID);
	return list;
}
#endregion

This is my processing screen, with some names changed.

using PX.Data;
using System;

namespace MyNamespace
{
    public class CUSTMyFileProcess : PXGraph<CUSTMyFileProcess>
    {
        #region Filters
        public PXCancel<CUSTMyItem> Cancel;
        public PXProcessing<CUSTMyItem> Items;
        #endregion

        #region Constructor
        public CUSTMyFileProcess()
        {
            Items.SetProcessCaption("Export");
            Items.SetProcessAllCaption("Export All");
            Items.SetProcessDelegate<CUSTMyItemEntry>(
            delegate (CUSTMyItemEntry graph, CUSTMyItem item)
            {
                try
                {
                    graph.Clear();
                    graph.Export(item, true);
                }
                catch (Exception e)
                {
                    PXProcessing<CUSTMyItem>.SetError(e);
                }
            });
        }
        #endregion

        #region Overridden Properties
        public override bool IsDirty => false;
        #endregion

    }
}

@Brian Stevens really appreciated