BasePages.PageBaseMaster.GetSortDirection C# (CSharp) Method

        public string GetSortDirection(string sortExpression)
        {
            if (ViewState[sortExpression] == null)
                ViewState[sortExpression] = "Asc";
            else
                ViewState[sortExpression] = ViewState[sortExpression].ToString() == "Desc" ? "Asc" : "Desc";

            return ViewState[sortExpression].ToString();
        }