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

by VB Migration Partner on Sep 26, 2010

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