private void LoadDirtyRooms() { DataSet dsDirtyRooms = new RoomDAO().SelectAllDirtyRooms(Master.CurrentCompany.CompanyId); dsDirtyRooms.Tables[0].PrimaryKey = new DataColumn[] { dsDirtyRooms.Tables[0].Columns["RoomId"] }; Session[Constants.SESSION_DIRTYROOMS] = dsDirtyRooms; if (dsDirtyRooms.Tables[0].Columns.Contains("CleanedDate") == false) { dsDirtyRooms.Tables[0].Columns.Add("CleanedDate", Type.GetType("System.DateTime")); } gvDirtyRooms.DataSource = (DataSet)Session[Constants.SESSION_DIRTYROOMS]; gvDirtyRooms.DataBind(); }