[yunqa.de] Re: License and work

  • From: Delphi Inspiration <delphi@xxxxxxxx>
  • To: yunqa@xxxxxxxxxxxxx
  • Date: Wed, 10 Sep 2008 18:57:10 +0200

Joan Dorrepaal wrote:

>I receive the same exception in my application (when set the
>ClientDataSet.Active property to True in D7). 

Just to be sure we are talking about the same thing, here is what I do in 
Delphi 7:

* Open DISQLite3_World_ClientDataSet.dpr

* Have the DatabaseName of the DISQLite3Database component point to the 
World.db3 database. The application does this during runtime, but you need to 
fill this value during design time.

* Select the ClientDataSet component and switch its Active property to True in 
the Object Inspector. For me, this results in the following error message (see 
attached screenshot as well):

"Access violation at address 4DB1C244 in module 'midas.dll'. Read of address 

As you see, the problem is in midas.dll. Quite a few bugs have been reported 
about midas.dll:


Since Borland did not publish the midas sources there is unfortunately not much 
we can do about it.

>But how then to me to work with your component?

* The problem might not be present for your particular data. My experience 
shows that midas.dll is especially sensitive to long text in WideString format. 
So even if midas has problems with DISQLite3_World_ClientDataSet, it might work 
well with your application's data. I was, for example, able to design 
DISQLite3_ClientDataSet_Grid after filling in the respective properties at 
design time which are otherwise set at runtime.

* Pick a Delphi version that does not exhibit the midas.dll problem. The above 
steps worked fine with Delphi 2007, for example.

* During design-time, fill in the DB controls' DataField properties manually 
instead of using the drop down.

* Set the DB control's properties during runtime.

>How can I load and update data?

Even though midas.dll in D7 shows the above design time problems, D7 can still 
compile DISQLite3_World_ClientDataSet without problems.

Hence the usual data load, modify, and update procedures as implemented in the 
code are working just fine.


Attachment: D7_AV_in_midas.dll.png
Description: PNG image

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