[DUG] graphics stops updating

[Matt Comb]

I would consider creating something like a stats object as an intermediary 
between your reading thread and the updating on the main thread. Something 
along the lines of the following.

Update the values that you need in the update events from the read thread, 
then on the mainform have a timer which also reads from this object.

Matt.


type
   TStatOb = class(Tobject)
   private
     fVal1:integer;
     fSC_Val1:tCriticalSection;
     function ReadVal1:integer;
     procedure SetVal1(value:integer);
   public
     constructor create;
     destructor destroy; override;
     property Val1:integer read ReadVal1 write SetVal1;
end;

implementation

{ TStatOb }

constructor TStatOb.create;
begin
    fSC_Val1:=tcriticalsection.create;
end;

destructor TStatOb.destroy;
begin
  fSC_Val1.free;
  inherited;
end;

function TStatOb.ReadVal1: integer;
begin
     fSC_Val1.Enter;
     result:=fval1;
     fSC_Val1.Leave;
end;

procedure TStatOb.SetVal1(value: integer);
begin
     fSC_Val1.Enter;
     fval1:=value;
     fSC_Val1.Leave;
end;


----- Original Message ----- 
From: "Ben Taylor" <to_ben at yahoo.com>
To: "NZ Borland Developers Group - Delphi List" <delphi at ns3.123.co.nz>
Sent: Sunday, June 19, 2005 4:55 PM
Subject: Re: [DUG] graphics stops updating


> hi,
>
> this indicates you are updating your ui from outside the main thread, 
> which is not
> allowed as the vcl is not threadsafe. it is unlikely to be a bug in your 
> audio
> components.
>
> you need to implement a threadsafe mechanism to update your ui, possibly 
> using
> critical sections or thread.synchronize.
>
> sorry, i don't have time to show an example right now.. maybe someone else 
> has a
> block of code to show?
>
> hope that helps,
> b
>
> --- Ross Levis <ross at stationplaylist.com> wrote:
>
>> Hi Ben
>>
>> I added the Assert.  I also had to turn on Asserts in the Compiler
>> options.  Execution stopped at the Assert.  Does this mean a bug in the
>> audio component I'm using?
>>
>> I'm using this excellent free audio component suite for Delphi, Kylix
>> and Lazarus.
>> http://www.compiler4.net/acs/index.html
>>
>> Thanks,
>> Ross.
>>
>> ----- Original Message ----- 
>> From: "Ben Taylor" <to_ben at yahoo.com>
>> To: "NZ Borland Developers Group - Delphi List" <delphi at ns3.123.co.nz>
>> Sent: Sunday, June 19, 2005 4:10 PM
>> Subject: Re: [DUG] graphics stops updating
>>
>>
>> add this to the procedure that updates the components. if it fails, then
>> you have a
>> threading issue.
>>
>> uses windows;
>> ..
>> Assert(GetCurrentThreadId=MainThreadID);
>>
>> otherwise, you'll probably need to show some code..
>>
>> --- Ross Levis <ross at stationplaylist.com> wrote:
>>
>> > The figures are coming from a thread and updating on an event, but
>> > this is not the
>> > problem.  I currently have 7 different controls on the screen showing
>> > the data
>>
>>
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