IndexViewer.SitecoreSearcher.GetQuery C# (CSharp) Method

        private QueryBase GetQuery(QueryInfo qi)
        {
            if (String.IsNullOrEmpty(qi.SearchString) ||
                String.IsNullOrEmpty(qi.FieldName) ||
                Index == null)
            {
                return null;
            }

            QueryBase query = null;

            switch (qi.QueryType)
            {
                case "FieldQuery":
                    query = new FieldQuery(qi.FieldName, qi.SearchString);
                    break;

                default:
                    query = new FullTextQuery(qi.SearchString);
                    break;
            }

            return query;
        }