Question

I have downloaded opensource delphi twain component (TDelphiTwain).
The interesting thing is, that when placed and saved on the form it creates bad dfm entry for itself.

  object DelphiTwain: TDelphiTwain
    OnSourceDisable = DelphiTwainSourceDisable
    OnSourceSetupFileXfer = DelphiTwainSourceSetupFileXfer
    TransferMode = ttmMemory
    SourceCount = 0
    Info.MajorVersion = 1
    Info.MinorVersion = 0
    Info.Language = tlDanish
    Info.CountryCode = 1
    Info.Groups = [tgControl, tgImage, tgAudio, MinorVersion]
    Info.VersionInfo = 'Application name'
    Info.Manufacturer = 'Application manufacturer'
    Info.ProductFamily = 'App product family'
    Info.ProductName = 'App product name'
    LibraryLoaded = False
    SourceManagerLoaded = False
    Left = 520
    Top = 136
  end

The problem is with the line:

   Info.Groups = [tgControl, tgImage, tgAudio, MinorVersion]

There are only three possible elements:

tgControl, tgImage and tgAudio

It adds MinorVersion everytime I Save the form.
When the app is run I get the error that there is invalid property for Info.Groups.
When i rmeove the bad part manually and without leaving dfm file the app starts ok.

I looked in the internet and there was one inquire regarding these strange issue, unfortunately it hasn’t been resolved.

I think that there is some sort of memory corruption. In the post in teh internet, strange signs were displayed …

Has anyone worked with that component or could give me some hint how this could be fixed?

Answer 1

The error seems to be in TTwainIdentity.GetGroups where result is not initialized. You can try to change the code by replacing

Include(Result, tgControl);

with

Result := [tgControl]; 

You have to recompile the package to make this change work inside the IDE.