Hello,
May somebody help me?

I'm making a program in Delphi6 and MapPoint2004 and
I used exactly the example in the code found at
http://www.mp2kmag.com/a80--delphi.a....mappoint.html.


function TFMain.Controll_Address(address:string):string;
02 var
03 ret:string;
04 r:FindResults;
05 o:OleVariant;
06 item:location;
07 line, street,city1,city2,region,postalcode:string;
08 country:Olevariant;
09 begin
10 line:=address;
11
......
....
r:=Mapp.ActiveMap.FindAddressResults(street,city1, city2, region, postalcode, country);
20
21
22
23 if r.Count>0 then
24 begin
25 o:=1;
26 item:=r.get_item(o) as location;
27 ret:=
28 item.Get_StreetAddress.Get_Street+','+ ......

WHEN I call the function Get_streetAddress.Get_street or get_city
I have a "Access violation at address 0045FE5C. Read of address 000000.

Thanks

Do you know which line the Access Violation occurs on?

I don't know Delphi but do know some Pascal. It was pre-COM, so I may only be able to provide limited help.
(eg. I don't know how Delphi handles COM objects - releasing them,etc)


Richard

Hi,

Read of address 000000

this means that you try to read at an addrss containing a null pointer. Eventually you can sset the debugger on 'break on exceptions' to see the offending line, or 'search' - 'find error' to go to the address pointer where the exception occure.

Hi Richard,

(eg. I don't know how Delphi handles COM objects - releasing them,etc)

Like in C. Create / destroy is the coder responcability

If the rror is at the last line, it might be because the list of locations probably includes some location objects which do not have their streets setting.

Location have a number of different properties and they are not necessarily all set!
Eg. if the Location object represents a country (and only a country) then none of the other proeprties will be set.

Richard

Hi Richard,

Yes you are right. He must something do as:

Code:

if Item <> nil then
   Item.CallMethod;

or

Code:

if Assigned(Item) then
   Item.CallMethod;

Both are the same.