On the day fixed, the court shall enter the default of all persons interested in the property described who have not appeared; and unless sufficient cause to the contrary be shown, shall appoint 3 disinterested persons as court commissioners whose duty it shall be to determine whether it is necessary to take for public use or benefit the property described in the petition and, if so, to appraise the damages to be paid as compensation for such taking. The commissioners shall not be residents of the area to be served by the improvement for which the property is to be taken. The court shall fix the time and place for the first meeting of the court commissioners and require their attendance; it may also authorize the court commissioners to adjourn their meeting from time to time not later than a day to be named, and shall fix the time for filing their report. After the appointment of court commissioners, no discontinuance shall be filed and no order of discontinuance may be entered, except upon payment by the county of the expenses of the proceeding and reasonable attorney fees of all parties in interest who have appeared in the proceedings under the order of the court.