C# Array.FindAll

private void Form1_Load(object sender, EventArgs e)
{
Room room1 = new Room("001", "name");
Room room2 = new Room("002", "name");
Room room3 = new Room("003", "name");

Room[] rooms = { room1, room2, room3 };

Room[] room_re = Array.FindAll<Room>(rooms, ifRoom);

foreach (Room item in room_re)
{
Console.WriteLine(item.roomid);
}

}

public bool ifRoom(Room r)
{
if(r.roomid == "001")
{
return true;
}
else
{
return false;
}
}
}

public class Room
{
public string roomid;
public string roomname;

public Room(string rooid, string roomname)
{
this.roomid = roomid;
this.roomname = roomname;
}
}