Document Object

    public class Document
    {
        
        private string docID;
        private string docType;
        private DateTime docCreated;
        private DateTime docUpdated;
        private string docCreatedBy;
        private string docUpdatedBy;
        private DocumentData d;
        public Document()
        {
            d = new DocumentData();
        }
        [BsonId]
        public ObjectId Id { get; set; }
        public string DocID
        {
            get
            {
                return this.docID;
            }
            set
            {
                try
                {
                    this.docID = value;
                    if (this.docID == "")
                    {
                        throw new Exception("DocumentID empty.");
                    }
                }
                catch (Exception e)
                {
                    throw new Exception(e.Message.ToString());
                }
            }
        }
        public string DocType
        {
            get
            {
                return this.docType;
            }
            set
            {
                try
                {
                    this.docType = value;
                    if (this.docType == "")
                    {
                        throw new Exception("DocumentType empty.");
                    }
                    switch (value)
                    {
                        case "Invoice": 
                            break;
                        default:
                            throw new Exception("Document type invalit or not found.");
                            break;
                    }

                }
                catch (Exception e)
                {
                    throw new Exception(e.Message.ToString());
                }


            }
        }
        //[BsonDateTimeOptions(DateOnly = true)]
        public DateTime DocCreated
        {
            get
            {
                return this.docCreated;
            }
            set
            {
                this.docCreated = value;
            }
        }
        //[BsonDateTimeOptions(DateOnly = true)]
        public DateTime DocUpdated
        {
            get
            {
                return this.docUpdated;
            }
            set
            {
                this.docUpdated = DateTime.Now;
            }
        }
        public string DocumentUpdatedBy
        {
            get
            {
                return this.docUpdatedBy;
            }
            set
            {
                this.docUpdatedBy = value;
            }
        }
        public string DocCreatedBy { get; set; }
        public IList<DFile> Files { get; set; }
        public void Save()
        {
            //Insert New Document Here.
 
            
            d.Save(this);
            
        }
        public void Add()
        {
            d.Add(this);
        }
        public void Update()
        {
            //Update Document Here.
        }
        public void FindByDocID(String DocID)
        {
            d.FindByDocID(DocID);
        }
        public void MergeFiles(Document doc)
        {
            //this.Files = this.Files.Concat(doc.Files).;
            foreach(DFile file in doc.Files)
            {
                this.Files.Add(file);
            }
            
        }
    }
    public class DFile
    {
        private string fileName;
        private ObjectId fileLocation;
        private DateTime fileCreatedDate;
        private DateTime fileUploadedDate;
        private ObjectId id;
        [BsonId(IdGenerator = typeof(ObjectIdGenerator))]
        public ObjectId Id 
        { 
            get 
            { 
                
                return this.id; 
            } 
            set 
            {
                ObjectId id = new ObjectId();
                this.id = id; 
            } 
        }
        public string FileName
        {
            get
            {
                return this.fileName;
            }
            set
            {
                this.fileName = value;
            }
        }
        public ObjectId FileLocation 
        {
            get
            {
                return this.fileLocation;
            }

            set
            {
                if (this.fileLocation == null)
                {
                    throw new Exception("File Location is empty.");
                }
                else
                {
                    this.fileLocation = value;
                }
            }
        }
        //[BsonDateTimeOptions(DateOnly = true)]
        public DateTime FileCreatedDate
        {
            get
            {
                return this.fileCreatedDate;
            }
            set
            {
                this.fileCreatedDate = value;
            }
        }
        //[BsonDateTimeOptions(DateOnly = true)]
        public DateTime FileUploadedDate
        {
            get
            {
                return this.fileUploadedDate;
            }
            set
            {
                this.fileUploadedDate = DateTime.Now;
            }
        }
        
    }