Visual FoxPro to Visual Basic .NET

529 Pages·2004·6.118 MB·English

by  Pinter, Les

Visual FoxPro to
Visual Basic .NET
Les Pinter
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Contents at a Glance
Introduction....................................................................................................1
1 Differences Between Visual FoxPro and Visual Basic .NET............................5
2 Building Simple Applications in Visual FoxPro and Visual Basic .NET.......79
3 Building a Visual FoxPro Application for SQL Server..................................99
4 AVisual Basic .NET Framework..................................................................135
5 Adding Internet Access...............................................................................161
6 Data Access..................................................................................................227
7 XML.............................................................................................................281
8 Screen Design..............................................................................................325
9 Searching and Filtering...............................................................................385
10 Reporting.....................................................................................................435
Index...........................................................................................................483
Table of Contents
Introduction 1
1 Differences Between Visual FoxPro and Visual Basic .NET 5
A Whole New World ......................................................................................5
The Integrated Development Environment (IDE) ........................................8
Typing Commands in the Command Window ...................................8
The Toolbox ..........................................................................................9
Tab Ordering .......................................................................................11
Projects and Solutions ........................................................................11
Compiler Output Formats ..................................................................13
The Code Window ..............................................................................14
The Document View Window ............................................................14
Bookmarks and Task Lists ...................................................................15
The Server Explorer ............................................................................15
What Can You DOin the IDE? ............................................................16
The Class Browser and Visual Basic .NET’s Class View ......................17
The Object Browser ............................................................................17
The Properties Window ......................................................................17
Getters and Setters Versus ASSIGNandACCESSMethods ...................18
Shortcut Keys ......................................................................................19
The Tools, Options Dialog ..................................................................20
The Task Pane Manager ......................................................................21
The Output Window and Your Application Menu ............................21
Customizing the IDE ..........................................................................22
The Visual Basic .NET Solution Explorer .....................................................22
Intermediate Language .......................................................................24
DLLs ....................................................................................................25
Other Characteristics of a Visual FoxPro Project ...............................25
Using Tables to Store FoxPro Project Components ...........................26
File Types Used in Visual Basic Projects .............................................27
Project Information ............................................................................28
Command Syntax ........................................................................................28
Flow of Control ............................................................................................30
Calling a Function, Procedure, or Method ........................................30
String handling ...................................................................................31
Ending Your Program .........................................................................31
Do...ENDDOand Other Loops in Visual FoxPro .................................31
Loops in Visual Basic .NET ...........................................................32
Conditional Execution in Visual FoxPro ...........................................33
Conditional Execution in Visual Basic .NET .....................................34
Variables, Enums, Arrays, Collections, and Fields ......................................35
Data Types ..........................................................................................35
Variable Scope Declaration in Visual FoxPro .....................................36
Variable Declarations in Visual Basic .NET ........................................38
Enumerations, Arrays, and Collections ..............................................40
Fields ...................................................................................................44
Functions and Subroutines (Procedures) .....................................................44
Function Declarations ........................................................................45
Summary of Visual Basic Declarations ...............................................50
Classes, Namespaces, Properties, and Forms ...............................................51
Instantiating objects in Visual Basic .NET .........................................56
Property Procedures in Visual Basic .NET ..........................................56
Forms ..................................................................................................58
Events ...........................................................................................................58
Events in Visual FoxPro ......................................................................59
Events in Visual Basic .NET ................................................................60
RaiseEvent ..........................................................................................62
How to Declare an Event in a Class ...................................................62
The Form .............................................................................................66
Compiler Directives .....................................................................................70
Data ..............................................................................................................71
Data Binding ................................................................................................74
Error Handling and Debugging ...................................................................75
TRY...CATCH ........................................................................................75
Debugging ...........................................................................................76
FoxPro Debugging Aids ......................................................................76
Visual Basic .NET Debugging Aids .....................................................77
Summary ......................................................................................................77
vi Visual FoxPro to Visual Basic .NET Side by Side
2 Building Simple Applications in Visual FoxPro 79
Building a Simple Application in Visual FoxPro..........................................79
Creating a Simple Form Controls Class Library ................................81
Field Mapping .....................................................................................81
Creating the Form Using Your Subclassed Controls ..........................82
Form Methods ....................................................................................82
Adding the Command Buttons ..........................................................83
Creating a Form Template ..................................................................87
Running the Form ..............................................................................89
Building a Simple Application in Visual Basic .NET ...................................89
Creating a Customers Table ...............................................................89
Designing the Form ............................................................................92
Creating a Dataset ..............................................................................92
Building the Form ..............................................................................93
Form Methods ....................................................................................93
Adding the Command Buttons ..........................................................94
Summary ......................................................................................................97
3 Building a Visual FoxPro Application for SQL Server 99
Why Three-Tier? ..........................................................................................99
Getting Our Test Data Ready ............................................................102
Creating the SQL Database and Loading Your Tables ...............................103
Writing the Sample Application ................................................................107
The Form Template ....................................................................................112
How to Use the FlatFileFormTemplate .........................................116
A Search Form Template ............................................................................117
How to Use the EasySearchTemplate .............................................122
The Data Tier .............................................................................................122
Running the Application ..................................................................133
What’s Next? ..............................................................................................134
4 AVisual Basic .NET Framework 135
Starting the New Windows Application Project .......................................135
The AppScreen Form Properties .......................................................137
Adding a Windows Controls Library .........................................................137
Building Your First Inheritable Form .........................................................141
Coding the Form Class .....................................................................144
Programming with Class ..........................................................................146
Automating Data Access ..................................................................147
Loading the List Box and Displaying a Record When Clicked ......150
Utility Routines ...............................................................................153
Contents vii
ClickEvent Code for the Form’s Buttons .................................................154
How the Button Code Works ...........................................................155
How to Use This Template ...............................................................158
Summary ....................................................................................................159
5 Adding Internet Access 161
ASP and Database Development ...............................................................161
Internet Access in Visual FoxPro 7 ............................................................164
Installing Web Connection ..............................................................164
Building Your Application ................................................................165
The Main Program ............................................................................166
TheStandardFormClass Template .............................................................169
The Internet Server ...........................................................................170
How Web Connection works ...........................................................171
Writing Web Connection Functions .........................................................173
Passing Parameters ............................................................................173
An XML Primer .................................................................................177
The Customer Form ..........................................................................178
Introducing the Server ...............................................................................180
TheSEND2DBFandSEND2SQLFunctions ............................................192
Database Design Still Matters ...........................................................194
Modifying the Data Tier to Add Internet Data Access ..............................194
Building XML Web Services with Visual FoxPro 8 ....................................208
XML Web Services in Visual Basic .NET ....................................................213
A Main Form for the Sample Application ........................................213
Building a Web Service for the Sample Application ........................214
Changes to the CONFIG.WEBFile .......................................................215
Web Service Functions ......................................................................215
How It Works ....................................................................................216
Adding References to the Web Service to Your Client ..............................217
Code for the Windows Application to Use the Web Service ...........219
How It Works ....................................................................................220
The EditCustomer Form ...................................................................221
How It Works ....................................................................................223
Using Remoting Instead of Web Services .........................................224
Summary ....................................................................................................224
viii Visual FoxPro to Visual Basic .NET Side by Side
6 Data Access 227
Data Access in Visual FoxPro Before Visual FoxPro 8 ...............................228
The DBF Format ................................................................................228
Creating a Table ................................................................................229
Using Local Tables (DBFs) ................................................................229
Aliases ...............................................................................................230
Cursors ..............................................................................................231
Supporting Cast ................................................................................231
Buffering ...........................................................................................232
Indexes ..............................................................................................233
Database Containers ..................................................................................233
Local Views .......................................................................................235
Remote Views ...................................................................................235
SQL Pass-Through .............................................................................235
Connections and Connection Strings ..............................................236
SQLExec() .........................................................................................237
Other SQL Commands .....................................................................237
The Upsizing Wizard ........................................................................239
New Features in Visual FoxPro 8 ...............................................................239
TheCursorAdapterClass .................................................................239
TheXMLAdapterClass .......................................................................247
FoxPro Data Access Notes and Comments ......................................254
Data Access in Visual Basic .NET ...............................................................254
Disconnected Data Access ................................................................254
Connections .....................................................................................255
Data Adapters ...................................................................................256
Datasets .............................................................................................261
Typed Datasets ..................................................................................262
The Data Form Wizard .....................................................................263
The Generated Code .........................................................................268
Data Binding .....................................................................................271
XML Web Services ............................................................................274
How to Use the Web Service ............................................................277
Summary ....................................................................................................279
7 XML 281
The Structure of XML ................................................................................282
Encoding ...........................................................................................284
Namespaces .......................................................................................284
Contents ix
Data Models: XDR and XSD .............................................................285
Examples of XML .............................................................................285
Representation of Complex Structures ......................................................287
Hierarchical XML .......................................................................................290
The Document Object Model ....................................................................293
Commands to Move Data Between a Table and XML ..............................295
CursorToXML() ..................................................................................295
XMLToCursor() ..................................................................................299
How FoxPro Implements XML ..................................................................302
Using XML to Read Other Types of Data .........................................302
Receiving XML Files Directly ...........................................................303
Importing XML into Visual Basic .NET .....................................................304
Direct Access to SQL Server with XML ............................................304
Using the XML DOM to Call a Web Service ....................................306
Using the XML DOM to Validate Documents .................................308
XMLUpdateGrams ...............................................................................309
DiffGramsin Visual FoxPro 8 ...........................................................312
The Visual FoxPro CursorAdapter ....................................................314
Creating a CursorAdapter to Read XML ..........................................316
Reading XML into a Visual Basic .NET Dataset ........................................320
The Visual FoxPro XMLAdapter .........................................................320
Using XML and Data Islands to Reduce Server Load ................................321
Data Islands ......................................................................................321
Related Technologies: XPATH and XSLT ...................................................323
Extensible Style Sheet Transformations (XSLT) .........................................324
Summary ....................................................................................................324
8 Screen Design 325
The Base Control Classes ...........................................................................325
Creating the Startup Screen for Your Application ....................................327
The Startup Screen for Your Visual FoxPro Application ..................328
The Startup Screen for Your Visual Basic .NET Application ............328
Creating Menus ..........................................................................................330
The FoxPro Menu .............................................................................330
The Visual Basic .NET MainMenuControl .........................................331
Traversing the Controls in a Form ...................................................332
Subclassing Controls ..................................................................................332
Subclassing the FoxPro Screen Controls ..........................................332
Using Your Subclassed FoxPro Controls ..........................................333
Subclassing the Screen Controls in Visual Basic .NET .....................335