> AMP wrote:
> > I have a List that adds members in the following fashion:
> > for (int i = StartingPortNumber; i < (UsablePorts +
> > StartingPortNumber); i++)
> >     {
> >         string PortName = "Com" + i;
> >         AllPorts.Add(new SerialPort(PortName));
> >     }
>
> > At some point I want to acess a particular member by refereing to the
> > PortName.
> > Can I do that with IndexOf?
>
> No. That's because .IndexOf() can only look for a particular SerialPort, not
> a SerialPort with a particular name. Because you don't store the reference
> to the SerialPort you created anywhere other than in the list itself, you
> can't look for it. If you create two SerialPort objects with the same port
> names, they are still two different objects.
>
> > I am asking(and not trial and error) because,as of right now the I am
> > not connected to the ports to experiment.
>
> There are three ways, one that works in this specific case and two that work
> generally.
>
> The specific solution is that there's a one-to-one correspondence between
> indexes and port names in this case. So if you're looking for "Com13", all
> you have to do is take .Substring(3), convert it to an integer, subtract
> StartingPortNumber, and there you go. Easy as pie! But not very stable.
>
> One non-specific solution that doesn't break when this assumption no longer
> holds is to go through the list and check for each SerialPort whether it has
> the name you're looking for. "AllPorts.Find(port => port.PortName ==
> myPortName)" will do it. "AllPorts.Find(delegate(SerialPort port) { return
> port.PortName == myPortName; })" if you're still stuck with C# 2.0.
>
> The most general solution is to use a Dictionary (or a SortedList or
> SortedDictionary), which can simply map port names to ports. This lookup
> does not require searching through the entire list every time, so it scales
> much better (that said, most systems have a limited number of serial ports,
> so it won't matter much in this particular case). SortedList and
> SortedDictionary are special Dictionaries that allow you to still access
> members by index. So for example:
>
>    SortedList<string, SerialPort> AllPorts = new SortedList<string,
> SerialPort>();
>    for (int i = StartingPortNumber; i < (UsablePorts + StartingPortNumber);
> i++) {
>      string PortName = "Com" + i;
>      AllPorts.Add(PortName, new SerialPort(PortName));
>    }
>
>    ...
>
>    SerialPort com13 = AllPorts["Com13"]; // or AllPorts.TryGetValue(...)
>    SerialPort com14 = AllPorts.Values[14 - StartingPortNumber];
>
> Of course, you don't have to use names if you know they all begin with "Com"
> anyway:
>
>    Dictionary<int, SerialPort> AllPorts = new Dictionary<int, SerialPort>();
>    for (int i = StartingPortNumber; i < (UsablePorts + StartingPortNumber);
> i++) {
>      AllPorts.Add(i, new SerialPort(PortName));
>    }
>
>    ...
>
>    SerialPort com13 = AllPorts[13];
>
> --
> J.