Getting error "Use of unassigned local variable"

Question

I have one functionality where i am having three modes based on that modes i am displaying my database records in my view for that i am using following code but i am getting following error

Use of unassigned local variable 'result'

this is my controller code

public PartialViewResult _LaundryBookingPart(DateTime? From, DateTime? To, int mode)
{
    List<RoomLaundryvw> result;
    if (mode == (int)ItemTypesEnum.LaundryGuest)
    {
        result = db.Query<RoomLaundryvw>($"Select rm.RoomID,rm.RoomNo,g.GuestID,g.GuestName,ln.LaundryID,it.ItemName,ln.PickDate,ln.ServiceKind,ln.DropQty,ln.DropDate from Laundry ln " +
        "inner join Items it on ln.ItemId = it.ItemId " +
        "inner join Rooms rm on ln.RoomID = rm.RoomID " +
        "left join Reservation_Guest rg on rg.ReservationID = ln.ReservationID " +
        $"left join Guests g on g.GuestID = rg.GuestID").ToList();
    }

    if (mode == (int)ItemTypesEnum.LaundryStaff)
    {
        result = db.Query<RoomLaundryvw>("Select au.RealName as GuestName from Laundry ln INNER JOIN AspNetUsers au ON ln.UserId = au.Id").ToList();
    }

    if (mode == (int)ItemTypesEnum.Linen)
    {
        result = db.Query<RoomLaundryvw>("Select rm.RoomID,rm.RoomNo,g.GuestID,it.ItemName,g.GuestName from Laundry ln " +
                 "inner join Items it on ln.ItemId = it.ItemId " +
                 "inner join Rooms rm on ln.RoomID = rm.RoomID " +
                 "left join Reservation_Guest rg on rg.ReservationID = ln.ReservationID " +
                 "left join Guests g on g.GuestID = rg.GuestID ").ToList();
    }
    return PartialView(result);
}

I am getting red line with above error.

Please help me with this.

@RobertHarvey It's relevant because it could leave a better solution by having a default case instead of a cascading elif chain — Maximilian Burszley, Feb 08 '19 at 15:26
`List result = null;` or `List result = Enumerable.Empty();` — Heretic Monkey, Feb 08 '19 at 15:26
@RobertHarvey i am getting this error Use of unassigned local variable 'result' — kunals, Feb 08 '19 at 15:26
@TheIncorrigible1: Else-if allows for a default case. He doesn't even have that. — Robert Harvey, Feb 08 '19 at 15:26
Just initialize `result` to `null` to keep the compiler happy. You know that there is no case in which `result` will not be assigned, but the compiler doesn't do enough flow analysis to know that. — Flydog57, Feb 08 '19 at 15:27
@Flydog57 How do you know there is no case? What in the above code guarantees that one of the `if` blocks will be run? — Kenneth K., Feb 08 '19 at 15:27
@KennethK. No, I don't know, but I'm assuming that the OP does. I'm using "you" in the impersonal. I hit cases like this all the time. If you look at my code, you will occasionally see variables that I might normally leave unassigned, assigned to a default with a comment saying "//keeping the compiler happy" — Flydog57, Feb 08 '19 at 15:28
@TheIncorrigible1 i don't have a default case i want to show that view for default case — kunals, Feb 08 '19 at 15:29
@Flydog57 Sounds completely safe for the coders that maintain this six months from now. /s — Kenneth K., Feb 08 '19 at 15:29

score 0 · Accepted Answer · answered Feb 08 '19 at 15:26

0

The problem is that you never specify a default value for result.

IE: It is possible for none of your If statements to execute and initialize the result variable.

answered Feb 08 '19 at 15:26

Tyler Sells

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Getting error "Use of unassigned local variable"

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