Solved

pointers, OLEVariant, Arrays of OLEVariant

Posted on 2001-09-13
4
1,443 Views
Last Modified: 2011-10-03
Can anybody point me to any documents which clearly explains how to use pointers with OLEVariant and Arrays of OLEVariant. I am being passed parameters of these types from a Server and need to extract the data that is being passed to my program. I am finding it all very confusing.

Thanks.
0
Comment
Question by:JohnMcGill
4 Comments
 
LVL 9

Accepted Solution

by:
ITugay earned 100 total points
ID: 6479481
Hi JohnMcGill,

you can use typecasting to convert pointer to integer and back.

var
  V: OLEVariant;
  T: TEdit;

begin
  V := Integer(Edit1);

  TEdit(Integer(V)).Text := 'some text';
end;

----
Igor.
0
 
LVL 14

Assisted Solution

by:AvonWyss
AvonWyss earned 100 total points
ID: 6479560
Arrays passed along in OLE automation are often pointers to so-called safe arrays (PSafeArray). These are arrays of OLE-compatible variants (OLEVariant). If you get a pointer to a safe array, you can quickly convert it to a OLEVariant array and vice-versa:

function SafeArrayToVariant(SaveArray: PSafeArray): OleVariant;
begin
    TVarData(Result).VType:=varArray;
    TVarData(Result).VArray:=PVarArray(SaveArray);
end;

The other way around goes like this:

function VariantToSafeArray(const Arr: OleVariant): PSafeArray;
begin
   Assert(TVarData(Arr).VType=varArray);
   Result:=PSafeArray(TVarData(Arr).VArray);
end;

[...]
var
    Strings: OleVariant;
    Temp: PSafeArray;
[...]
    {I assume that Temp holds the PSafeArray)
    Strings:=SafeArrayToVariant(Temp);  

And when it is in the Variant, you can just use it like a normal Pascal array...:

   Edit1.Text:=Strings[0];  

Hope this helps!
0
 
LVL 17

Expert Comment

by:geobul
ID: 9307969
No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:

split points between ITugay and AvonWyss

Please leave any comments here within the next seven days.

PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!

Thanks,

geobul
EE Cleanup Volunteer
0

Featured Post

3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

In this tutorial I will show you how to use the Windows Speech API in Delphi. I will only cover basic functions such as text to speech and controlling the speed of the speech. SAPI Installation First you need to install the SAPI type library, th…
Hello everybody This Article will show you how to validate number with TEdit control, What's the TEdit control? TEdit is a standard Windows edit control on a form, it allows to user to write, read and copy/paste single line of text. Usua…
This Micro Tutorial will teach you how to censor certain areas of your screen. The example in this video will show a little boy's face being blurred. This will be demonstrated using Adobe Premiere Pro CS6.
Along with being a a promotional video for my three-day Annielytics Dashboard Seminor, this Micro Tutorial is an intro to Google Analytics API data.

803 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question