 |
BorlandTalk.com
Borland discussion newsgroups
|
| View previous topic :: View next topic |
| Author |
Message |
Guest
|
 Posted: Thu Mar 08, 2007 10:31 pm Post subject: how to pass a record to a component? |
 |
|
hi, i have a question,
if i try to run the following code i get the error "Left side cannot
be assigned to".
i understand that this has something to do with the usage of TypeA.
My question is, how can you pass records to components? because,
apparently, the following approach does not work.
thank you all in advance,
Type TypeA=record
some_int:integer;
some_real:real;
end;
Type TypeB = class(TComponent)
private
PrivateA: array of TypeA;
function GetA(index:integer):TypeA;
procedure SetA(index:integer;value:TypeA);
public
procedure SetLengthA(i:integer);
property A[i:integer]:TypeA read GetA write SetA;
end;
procedure TypeB.SetLengthA(i:integer);
begin
setlength(PrivateA,i);
end;
function TypeB.GetA(index:integer):TypeA;
begin
result:=PrivateA[index];
end;
procedure TypeB.SetA(index:integer;value:TypeA);
begin
PrivateA[index]:=value;
end;
procedure TForm1.Button1Click(Sender: TObject);
var B: TypeB;
begin
B:=TypeB.create(nil);
B.SetLengthA(3);
B.A[1].some_int:=5; // <----------- this causes the error !
end; |
|
| Back to top |
|
 |
ils
Guest
|
| Posted: Mon Mar 12, 2007 3:50 pm Post subject: Re: how to pass a record to a component? |
|
|
On 8 อมา, 19:31, Poetj...@gmail.com wrote:
| Quote: | hi, i have a question,
if i try to run the following code i get the error "Left side cannot
be assigned to".
i understand that this has something to do with the usage of TypeA.
My question is, how can you pass records to components? because,
apparently, the following approach does not work.
thank you all in advance,
Type TypeA=record
some_int:integer;
some_real:real;
end;
Type TypeB = class(TComponent)
private
PrivateA: array of TypeA;
function GetA(index:integer):TypeA;
procedure SetA(index:integer;value:TypeA);
public
procedure SetLengthA(i:integer);
property A[i:integer]:TypeA read GetA write SetA;
end;
procedure TypeB.SetLengthA(i:integer);
begin
setlength(PrivateA,i);
end;
function TypeB.GetA(index:integer):TypeA;
begin
result:=PrivateA[index];
end;
procedure TypeB.SetA(index:integer;value:TypeA);
begin
PrivateA[index]:=value;
end;
procedure TForm1.Button1Click(Sender: TObject);
var B: TypeB;
begin
B:=TypeB.create(nil);
B.SetLengthA(3);
B.A[1].some_int:=5; // <----------- this causes the error !
end;
|
1. use pointer to record TTypeA like
type
PTypeA = ^TTypeA;
2. use "array of PTypeA" instead of "array of TTypeA"
3. don't forget to allocate memory for all elements of that array |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
