Disco.Services.DocumentTemplateExpressionExtensions.EvaluateOnAttachmentImportExpression C# (CSharp) Method

        public static string EvaluateOnAttachmentImportExpression(this DocumentTemplate dt, IAttachment Data, DiscoDataContext Database, User User, DateTime TimeStamp, List<DocumentUniqueIdentifier> PageIdentifiers)
        {
            if (!string.IsNullOrEmpty(dt.OnImportAttachmentExpression))
            {
                var compiledExpression = dt.OnImportAttachmentExpressionFromCache();
                var evaluatorVariables = Expression.StandardVariables(dt, Database, User, TimeStamp, null);
                evaluatorVariables.Add("PageIdentifiers", PageIdentifiers);
                var result = compiledExpression.EvaluateFirst<object>(Data, evaluatorVariables);
                if (result == null)
                    return null;
                else
                    return result.ToString();
            }
            return null;
        }