Compare List with string LINQ

DataTable dtOpenVacancy = ViewState["vwOpenVacancy"] as DataTable;

                var allData = dt3.AsEnumerable().Where(p => p.Field<string>("institute") != null);

 allData.Where(a => dtOpenVacancy.AsEnumerable().Select(q => q.Field<string>("disciplinename")).Contains( a.Field<string>("discipline")) && dtOpenVacancy.AsEnumerable().Select(q => q.Field<string>("institutename")).Contains(a.Field<string>("institute"))  && dtOpenVacancy.AsEnumerable().Select(q => q.Field<int>("cadreid")).Contains(int.Parse( ddlCadreType.SelectedItem.Value))).Count();

reference:- https://stackoverflow.com/questions/14257360/linq-select-objects-in-list-where-exists-in-a-b-c