I think you are doing a little extra work than you have to...and, as they
say, too much is exactly as wrong as too little ;-)
.
.
P := LstGetSelectionText(List, Selection); { Goood, obtains pointer to the
text }
{ The following line should not be necessary, since a string is directly
returned! }
ListText := MemHandleLock(P);
{ This line is also not neccessary, since you haven't allocated any memory
so you can free it! }
MemHandleFree(P);
.
.
The point is, that after you make the LstGetSelectionText() call, you do
have what you want - the P variable points to the memory where the string is
placed.
For you as a Pascal developer this might be a little unusual, since Pascal
strings are not the same as C strings. I am afraid you will have to get used
to that. What you get as return from that function is a C string, that is,
address in the memory, where the actual text is placed and it is
zero-terminated, as opposed to size-headed.
You may also want to change the P variable type from MemPtr to CharPtr and
eventually typecast when doing the call.
To make sure this is right, do the following:
P := LstGetSelectionText(List, Selection);
FrmCustomAlert(AlertShow, CharPtr(p), '', '');
Depending on how FrmCustomAlert() is done in your Pascal enviornment, you
may have to call a function like PascalString2CString(); I do not know the
exact name, but if FrmCustomAlert() expects Pascal string, then you
obviously have to convert P to it first.
- bobby
> -----Original Message-----
> I am trying to learn about the Popup List and as part of my
> "learning" application, I have a List (ListVarietal - a list
> of varieties of wine :-) !!). When a slection is made, I
> want to put up a Alert box to tell me what was selected -
> just part of learning. Well, I am not sure how to handle the
> strings - even after reading the "Bible". Now, some of my
> Procedures/Functions are slightly different from "C" (I can
> read "C", but I am not a proficient "C" programmer - Delphi
> instead). Below is my
> Event handler, but everything goes South!! I get the message
> that I am trying to access memory that should not be
> accessed. I understand this (thanks to the "Bible"), but I
> do not know how to retrieve the Item and convert it to text
> that can be put into the Alert (once I am comfortable doing
> that, I will put it into an "Edit" field).
>
> procedure PopuptriggerVariety_OnPopSelect(var Handled:
> Boolean; ControlID: UInt16; ControlP: ControlType; ListID:
> UInt16; ListP: ListType; Selection: Int16; PriorSelection: Int16);
> var
> Form: FormPtr;
> List: ListPtr;
> ListIndex: UInt16;
> P: MemPtr;
> ListText: PChar;
> begin
> FrmCustomAlert(AlertShow, 'Here I am!, '', '');
> Form := FrmGetActiveForm;
>
> //From here on I am lost!!!!
>
> //The name of the List is ListVariety
>
> ListIndex := FrmGetObjectIndex(Form, ListVariety);
> List := FrmGetObjectPtr(Form, ListIndex);
> P := LstGetSelectionText(List, Selection);
> ListText := MemHandleLock(P);
>
> MemHandleFree(P);
> Handled := True;
> end;
--
For information on using the Palm Developer Forums, or to unsubscribe, please see
http://www.palmos.com/dev/tech/support/forums/
