Basta! 2010 - VB6 Migration: Tips, Traps, and Techniques

Francesco Balena – Code Architects, Italy VB6 Migration: Tips, Traps, and Techniques

Me.About the Programming Microsoft Visual Basic series MSDN Regional director, Italy VB Migration Partner www.vbmigration.com

Code Architects Visual Studio Industry Partner ( VSIP ) the only Microsoft ISVNXT partner specialized in conversion and modernization of VB6 apps customers in Europe, United States & Canada, Australia and Asia dozens of millions of lines of code migrated official Microsoft Case study published on Microsoft.com, ERP system of about 1M lines of code

migration FAQs why migrating to .NET migrating vs. porting vs. extending using conversion tools the C# alternative

“ language impedance”  data types  type-char suffix  Array lower bounds  Optional params  As New variables  Byval argument passing  Defxxx  array rank  missing As  As Any parameters  block variables  date as double  array assignments  callbacks in Declare  As New arrays  UDT initialization  Variants  default parameterless members  Gosub  On Goto/GoSub  Byref ParamArray  Fixed-length strings  UDT assignments  byte-oriented string functions  enum/number conversions  IsMissing  Empty value  Null propagation  VarPtr, ObjPtr, StrPtr  class termination  IDisposable objects  default members in late-binding  OLE control  Line and Shape controls  control arrays  graphic methods  ScaleMode property  DrawMode property  DAO and RDO data-binding  ADO data-binding  ADO data-bound classes  DataEnvironment  VBControlExtender object  PropertyPages  UserDocuments  “classic” drag-and-drop  OLE drag-and-drop  Extender and Ambient properties  DDE  WebClasses  DHTML Pages  Sub Main in DLLs  SingleUse classes  Global classes  COM+ components  class persistence  Print and Printers  App, Screen, Forms objects  ActiveX EXEs  popup menus 

“ language impedance” (UW)

“ language impedance” (VBMP)

hidden traps strings parameter passing math operations collections fields ... and a lot more

concepts parser and code analyzer pre/post processing migration pragmas code generation engine support library code analysis & refactoring

concepts (in 75 minutes) parser and code analyzer pre / post processing migration pragmas code generation engine support library code analysis & refactoring

before migrating... use array with Lbound = 0 avoid Variants, if possible late binding Null propagation create wrapper methods file I/O graphics data access Windows API calls (As Any, VarPtr, StrPtr) remove unused and unreachable code

support library many VB6 methods are missing or don’t preserve functional equivalence CDate, IsDate, IsObject Str, StrConv AscB, ChrB, LeftB, MidB, RightB, ... MsgBox, InputBox FileDateTime, Dir VarType, TypeName IsMissing, IsEmpty, IsNull DoEvents SavePicture, LoadPicture ...

post-processing process the output from UW leverage existing upgrade warnings can‘t replace a real parser, but it’s enough for many common issues

post-processing examples library methods DoEvents Controls.Add UDT initialization fixed-length strings inside UDT default methods in late-binding mode

migration pragmas similar to compiler directives special remarks with '## prefix '## ArrayBounds ForceZero project, file, method, variable scope '## project:ConvertGosubs True '## myvar.InferType convert-test-fix methodology

migration pragmas examples ExcludeStatement InsertStatement ReplaceStatement AutoNew AutoDispose ReplaceCurrentFile IncludeFile

refactoring with PostProcess Not x Is y  x IsNot y Dim x As Short : x = 1  Dim x As Short = 1 Dim x As Short: For x = 1  For x As Short = 1 While…End While  Do…Loop If x = True Then  If x Then If x = False Then  If Not x Then If bool1 And bool2  If bool1 AndAlso bool2 … If bool1 Or bool2  If bool1 OrElse bool2 … more details here: www.vbmigration.com/blog

VB Migration Partner VB6 project groups all VB6 keywords (except VarPtr, ObjPtr, StrPtr) advanced code analysis and refactoring 70+ VB6 controls, drag-and-drop, popup menus graphic methods, user-defined ScaleMode null propagation in expressions (the VB6Variant type) ADO, DAO, RDO data-binding try-catch, gosubs, nested Ifs, type inference ADODB -> ADO.NET migration (ADOLibrary) pragmas & convert-test-fix methodology

VB6 migration: tips, traps, and tricks knowledge base, videos, code samples, articles, links, and resources at www.vbmigration.com slides available at www.slideshare.net/VBMigrationPartner blog www.vbmigration.com/blog LinkedIn Group on VB6 Migration www.linkedin.com/groups?gid=3074090 Facebook Fan Page on VB6 Migration facebook.com/FrancescoBalenaOnVB6Migration

Get free advice Each VB6 application is different and creates unique challenges in the migration to .NET. To learn more about your VB6 applications, run VB6 Analyzer on your source code and send us the generated text file. You will receive a detailed report on your VB6 applications and how VB Migration Partner can help you to quickly and effectively migrate it to .NET. www.vbmigration.com/getfreeadvice.aspx

Basta! 2010 - VB6 Migration: Tips, Traps, and Techniques

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