Why??

Question

public DataSet GetClass() { SqlConnection myConnection=new SqlConnection(ConfigurationSettings.AppSettings["connectionString"]); SqlDataAdapter countCmd=new SqlDataAdapter("select *,(select count(*) from Class where ParentId=g.SubId) as nCount from Class g",myConnection); DataSet dstClass=new DataSet(); countCmd.Fill(dstClass); return dstClass; } DataBinder.Eval: 'System.Data.DataRowView' does not contain a property with the name nCount. why? Is anybody could help me?