A very large .VBP - Visual Basic 6.0 project for those who are only familiar with the .vbproj extension :)

17. September 2011 16:36 by jpena in General  //  Tags: , , , , , , ,   //   Comments (0)

I just came back from executing a Ready assessment for a company in Minnesota, where I analyzed 740,000 lines of code in a VB6 application, of which 660,000 belonged to a single Visual Basic project (.vbp).  This is actually the largest single .vbp I have seen so far, beating the previous record of about 500,000 lines of code held by an European company.  We have migrated plenty of applications that contain 1+ million lines of code, but they are usually distributed across many .vbp’s.

Though unusual, single vbp’s of this size are perfectly manageable from a migration standpoint, and here are some things that can be done to deal with them:

  • Ensure that the migration computer has at the very minimum, 3GB of RAM. 
  • Look for customization opportunities before you start migrating the code.  Customizing the VBUC for this specific VBP can reduce manual effort drastically.
  • When making manual changes, start with a small team until you get the project to compile, especially if migrating to VB.NET as the compiler has a maximum of build errors that it can show at any given time. 
  • Once the application compiles, increase the team size and go for Visual Equivalence by distributing the different forms and user controls across your developers.

Dealing with Crystal Reports

13. September 2011 03:43 by jpena in General  //  Tags: , , , , ,   //   Comments (0)

Crystal Reports was one of the most popular reporting engines in VB6, and still holds a strong market presence with its .NET version.  However, the object model in the .NET version of Crystal has changed so dramatically from the VB6 days that automating this conversion is not be cost-effective in most cases.  These are the options when dealing with Crystal Reports in an application to be migrated to .NET:

  • Use COM Interop: we have successfully migrated many applications with Crystal Reports through COM Interop.  However, this only works when the report objects are populated using Crystal’s own querying engine (for example, sending a SQL string to Crystal so it can retrieve the data directly from the database), instead of providing an already-populated RecordSet as a data source for the report.  This is because once the application is ported to .NET, its RecordSets will become ADO.NET DataSets (or Helper Classes inheriting from DataSet), which will not be compatible with the legacy version of Crystal.  This can be fixed this by disabling the conversion of ADO to ADO.NET, but this is not desirable in most enterprise applications, and may compromise future maintainability and enhancements.
  • Replace with Crystal .NET or another .NET-compatible reporting engine: this is also a popular option among our clients, as it removes the legacy Crystal component.  On the other hand, this replacement is manual and will require adjustments to the report layout, if converting to the .NET version of Crystal, or even a rewrite of the reports if migrating to other engines.