Newbie having problems with an ArrayList

  • Thread starter Thread starter Abe Frohnman
  • Start date Start date
A

Abe Frohnman

Hello all,

I'm having problems using an ArrayList. The two lines of relevant code
are here:

roomsArray.Add(new Area(roomNumber));

labelRoomNumber.Text = "You're currently building room number " +
(Area)(roomsArray[0]).RoomNum;

When I try to compile this, I get this error message: 'object' does not
contain a definition for 'RoomNum'.

How can I access a method from my Area class when its part of an ArrayList?

Thanks!

~af
 
Abe Frohnman said:
I'm having problems using an ArrayList. The two lines of relevant code
are here:

roomsArray.Add(new Area(roomNumber));

labelRoomNumber.Text = "You're currently building room number " +
(Area)(roomsArray[0]).RoomNum;

When I try to compile this, I get this error message: 'object' does not
contain a definition for 'RoomNum'.

How can I access a method from my Area class when its part of an ArrayList?
Click to expand...

Currently it's being parsed as:

(Area) ( roomsArray[0].RoomNum )

You just need to cast slightly differently:

((Area)(roomsArray[0])).RoomNum
 
So does the dot operator have a higher precedence than casting? In C++
its the other way around.

Jon said:
Abe Frohnman said:
I'm having problems using an ArrayList. The two lines of relevant code
are here:

roomsArray.Add(new Area(roomNumber));

labelRoomNumber.Text = "You're currently building room number " +
(Area)(roomsArray[0]).RoomNum;

When I try to compile this, I get this error message: 'object' does not
contain a definition for 'RoomNum'.

How can I access a method from my Area class when its part of an ArrayList?
Click to expand...


Currently it's being parsed as:

(Area) ( roomsArray[0].RoomNum )

You just need to cast slightly differently:

((Area)(roomsArray[0])).RoomNum
Click to expand...
 
Abe Frohnman said:
So does the dot operator have a higher precedence than casting? In C++
its the other way around.
Click to expand...

To be honest, I've never learned the precedence - I put enough brackets
in to make it absolutely obvious to me where the cast goes, and that's
always enough for the compiler :)
 
In C++ its the other way around.
I think you will find . and -> are higher precedence in C++ as well

Regards
Lee
..
Abe Frohnman said:
So does the dot operator have a higher precedence than casting? In C++
its the other way around.

Jon said:
Abe Frohnman said:
I'm having problems using an ArrayList. The two lines of relevant code
are here:

roomsArray.Add(new Area(roomNumber));

labelRoomNumber.Text = "You're currently building room number " +
(Area)(roomsArray[0]).RoomNum;

When I try to compile this, I get this error message: 'object' does not
contain a definition for 'RoomNum'.

How can I access a method from my Area class when its part of an
Click to expand...
ArrayList?


Currently it's being parsed as:

(Area) ( roomsArray[0].RoomNum )

You just need to cast slightly differently:

((Area)(roomsArray[0])).RoomNum
Click to expand...
Click to expand...
 
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