protected override IDocument OpenCore(string fullFilePath)
        {
            XDocument solutionXML = XDocument.Load(fullFilePath);

            SolutionDocument document = new SolutionDocument(this, solutionXML);
            return document;
        }
        public bool CloseSolution()
        {
            if (!CanDocumentsClose(OpenedDocuments)) { return false; }

            SolutionDoc = null;
            ActiveDocument = null;
            while (OpenedDocuments.Any())
            {
                fileService.RemoveDocument(OpenedDocuments.First());
            }
            return true;
        }