Review of the free version of Delphi. Delphi Free Review Build Multi-Platform Applications

In early May of this year, Borland Software Corporation, a well-known manufacturer of development tools and middleware, announced a new, sixth version of Delphi, a tool for rapid development of Windows applications, which has long been the leading product of this company and is still very popular in our country. In this article, we'll take a quick look at what's new in this product compared to the previous version. We assume that the readers are familiar with previous versions of Delphi; for those who are not familiar with this product, we can recommend referring to the books on previous versions - there are more than enough of them published in Russian.

What's new in the development environment

All open component packages are now displayed in the project manager. This can be convenient when writing components: in the process of testing them, you can work simultaneously with both a project intended for testing components and a package that contains the component under test.

A new element has appeared in the development environment - the Object TreeView, which displays the hierarchy of application components in terms of their belonging to each other (Fig. 1). In the object tree, you can perform drag-and-drop operations, moving child components to other containers, and these changes are synchronously displayed in the form editor.

Note that components that do not have key properties defined are marked with question marks in the object tree, which immediately attract attention. In addition, the object tree also displays implicitly created components (Fig. 2).

The code editor now has the ability to select view modes using the shortcuts at the bottom of the code editor (the list of available modes depends on the type of application you are creating). In general, in addition to displaying the actual application code, the following display modes are available:

• Diagram - display of connections between data access components like the data module editor from the previous version of Delphi);
• HTML Scrip - displaying HTML and JavaScript code generated by components that are designed to create interactive Web applications (for more details, see the article "Developing Internet Applications Using Borland Delphi and Kylix" in this issue of the journal);
• HTML Resul - displays the HTML code generated when using the HTML template;
• Preview - Displays the generated HTML output as it appears in the client browser (Figure 3).

There is also something new in the object inspector. In particular, if the property value is a component, then it is displayed in a different color, and if you click on it, you can expand the list of its properties. In our opinion, this is a rather convenient innovation (Fig. 4).

The read-only properties are now also displayed in a different color. In addition, you can specify what colors to display in the object inspector - for this purpose, use the Object Inspector Properties dialog (Fig. 5).

The Code Insight and Code Completion tools have also undergone some changes. So, now you can use the Code completion tool in the module interface section, get a list of virtual methods, properties and interface methods, filter the values \u200b\u200bof elements in the list. The appearance of the Code Completion drop-down list has slightly changed: elements of different types are displayed in different colors, a list of parameters appears along with the method name, and the size of the list box can now be changed (Fig. 6).

Note that the new version provides a separate toolbar for creating Web applications (Fig. 7).

Compiler changes

Let's briefly list some of the changes made to the compiler:

• all procedures and functions intended for working with Variant data types have been removed from the System module and moved to the new Variants module. Note that in Delphi 6 you can create your own variant data types - the corresponding classes must inherit from the TcustomVariantType class;
• the Consts.pas module is split into two parts: Consts.pas and RTLConsts.pas;
• the $ IFDEF compiler directive supports the evaluation of expressions using constants, for example: ($ IF Defined (WIN32) and (MyValue\u003e 1)) ... ($ ENDIF)

  Pascal constants can also be used in these expressions, and you can check whether they are declared, for example:

  ($ IF Declared (SomeConst)) ... ($ ENDIF)

• Delphi 6 contains a new inline assembler. Detailed information about it (as well as some other changes made to the compiler) can be found in the product help system.

New in VCL and RTL

The Visual Component Library, as it always happens with the release of the next version of Delphi, has been replenished with new components. Among the components for creating user interfaces for Windows applications, it should be noted:

• TLabeledEdit - a field for entering text with a label (Fig. 8);
• TValueListEditor - a component designed to display a list of pairs of "parameter-value" type, similar to that shown in the object inspector (Fig. 9);
• TComboBoxEx - a combo box that allows you to display graphic images next to text (Fig. 10);
• TColorBox is a combo box for choosing a color (Fig. 11).

Many of the components have acquired additional properties (for example, to indicate how component borders look like BevelEdges, BevelInner, BevelOuter, BevelKind, BevelWidth).

Another innovation in VCL is the ability to use so-called subcomponents as properties, that is, components owned by another component rather than a form. In other words, a property of any component can be a reference to a component, which is either a regular component or a subcomponent. This means that the properties of the subcomponents should now be available in the property list of the owner components, and for this purpose the corresponding changes were made to the object inspector, which were mentioned above.

The TActionList component in one of the previous Delphi versions made it much easier to create user interfaces for applications. Delphi 6 adds new components to work with TAction objects - TActionManager (for storing a collection of Taction objects; Fig. 12), TToolActionBar and TMainMenuActionBar (interface elements designed to provide the user with access to the functionality described in TAction objects).

Note that you can create menu items in the TMainMenuActionBar component and buttons on toolbars created using the TtoolActionBar components by transferring the corresponding objects using the drag-and-drop method from the TActionManager component property editor. Delphi 6 also contains an impressive set of standard TAction components.

Several new properties and events have appeared for the TTreeView, TMenuItem, TListView, TCheckListBox, THeaderControl, TDateTimePicker, TDBLookupListBox, TDBLookupComboBox, TDBComboBox, TDBListBox, TOpenDialog, TListView, TScreen TComponentList, TClassList, TCollection, TStack, TQueue, TObjectStack, and TObjectQueue. Several new classes have also appeared, eg. TCustomListControl, THashedStringList)

Properties of type Interface can now be published if there is at least one component that implements this interface.

Other changes in the VCL and RTL include the presence of some new functions for working with date and time, a couple of new functions for working with dynamic arrays, several new standard colors, including clMoneyGreen - gray-green like a dollar (oh, those Americans who consider your country is the navel of the earth and the center of the universe!). Note also that many functions for working with Variant data now call not Windows API functions, but functions from the Variants.pas module - this was done to support multi-platform application development.

Database Applications: What's New?

Delphi 6 introduces a new universal data access mechanism - dbExpress. To use it in applications, Delphi 6 contains data access components and database drivers that implement the interfaces of this universal data access mechanism using the client API of the corresponding server DBMS. Delphi 6 delivery set includes dbExpress drivers for InterBase, Oracle, DB2, MySQL. The dbExpress drivers are one DLL, and they are usually the only one required when shipping client applications that use dbExpress. DbExpress was developed by Borland but is open source, so you can create dbExpress drivers for your applications as needed.

All of these features set dbExpress apart from the BDE library traditionally used in Delphi and the only supported universal data access engine before Delphi 5 introduced ADO component-level support. BDE, being a descendant of the Paradox Engine library, has retained many of the features of the desktop database access mechanism that cannot always be successfully applied when working with server-side DBMS. We can say that by now the question of replacing the universal data access mechanism with a more relevant modern needs has already ripened, especially since such a mechanism still needed to be developed when creating Kylix - the Linux version of Delphi (you can find an article about Kylix in this issue of the journal ).

However, BDE is still supported in Delphi 6, so there is no need to rewrite legacy applications that use this data access mechanism yet.

Due to the fact that Delphi now supports three generic data access mechanisms: BDE, ADO, and dbExpress, the component palette has been reorganized somewhat (Figure 13).

Note that in Delphi 6 there is no MIDAS page in the component palette (and the term MIDAS itself has been deprecated). Components for distributed applications have been moved to the new DataSnap page, which also contains several new components (Figure 14).

The main components of dbExpress data access include:

• TSQLConnection is a component that provides a connection to the database and interacts directly with the dbExpress driver;
• TSQLDataSet - a client dataset that implements the functionality of a unidirectional cursor (the dbExpress library itself allows you to create only a unidirectional cursor, since it does not buffer data in the client application);
• TSQLQuery, TSQLStoredProc, and TSQLTable are client datasets that also implement unidirectional cursor functionality and are designed primarily for compatibility with their respective BDE components in legacy applications that replace the BDE with dbExpress.

If you need to edit the data obtained with dbExpress, you can use the TClientDataSet or TSQLClientDataSet components. Delphi 6 has three new classes to implement client datasets cached in the client application's RAM: TBDEClientDataSet, TSQLClientDataSet, TIBClientDataSet, which are descendants of the new base class TСustomClientDataset, intended for use with different data access mechanisms.

The TClientDataSet component has gained several additional properties related to handling trailing spaces in string data, accessing data packets in XML format, changing the data access component, and choosing a data source. In addition, several components have appeared that allow you to convert client datasets to XML and vice versa.

The TUpdateSQL component has also undergone some changes: now it can be used not only with BDE datasets, but also with other datasets; you can also use several of these components when caching data using client datasets. It should be noted that client datasets, which appeared in Delphi 3 only as a means of caching data in the presentation layer of distributed applications, gradually became the main mechanism for working with databases in all applications, regardless of their architecture. However, this was to be expected - after all, many developers have been using them for this very purpose for a long time.

To support client datasets in distributed applications, two new components have been created: TSharedConnection, which allows a client application to access multiple remote data modules on the same server, and TLocalConnection, for use with data providers that are contained in the same application as the client dataset.

When discussing database support in Delphi 6, one cannot help but dwell on ADO support. Unfortunately, nothing new has appeared here - neither a query editor, even remotely resembling SQL Builder, nor bug fixes in the help file (for example, in the list of methods of the TADOStoredProc component there is still no reference to ExecProc - one of the most important methods of this component); as before, there is no OLAP support, except for the presence of DecisionCube components, which still do not work with ADO sources; there is no component-level support for the new objects introduced in ADO 2.5 and 2.6. It seems that ADO support in Delphi has received little attention this year. But such annoying little things can make someone think about the fact that there are other development tools ...

XML support

Delphi 6 supports the creation of applications that use XML documents and allow them to be integrated into database applications. In particular, this product contains several different tools for working with XML documents:

• components and interfaces for working with XML documents in applications;
• XML Data Binding wizard that generates classes to represent a specific XML document;
• components and utilities for converting XML documents into data packages and vice versa, including the XML Mapping Tool (Figure 15).

The new version allows you to work with XML documents in the same way as with regular databases. Support for using XML in database applications relies on components that convert data packets to XML documents and vice versa. To use these components, you must define the appropriate rules for converting XML to data packets and vice versa, which is done using the XML Mapping Tool. After defining the transformation rules (saved in a file), you can either convert the XML document to a client dataset, or work with it like a database, reading the data and saving the editing results in it.

New tools for creating Internet applications

The tools for creating Internet applications have undergone significant changes in the new version of Delphi. Now Delphi supports Web services and writing clients for them using SOAP, creating applications for Apache and much more (you can also read about what's new in the tools for creating Web applications in Delphi 6 in the article "Developing Internet Applications using Borland Delphi and Kylix ").

CORBA support

Three years after the VisiBroker acquisition, Delphi finally includes the IDL2PAS compiler for building CORBA servers and clients. It can be used to generate code for stub and skeleton objects in Pascal (until now, VisiBroker users could generate the corresponding code only in C ++ and Java, which excluded full CORBA support in Delphi - early CORBA support was based on using COM for this purpose ). The IDL2PAS compiler is available through the Tools | Regenerate CORBA IDL files menu item in the Delphi development environment.

Delphi's full CORBA support means that you can now create client applications for CORBA servers built with other development tools and programming languages \u200b\u200b(such as C ++ or Java), as well as for CORBA-enabled application servers (mainly Borland Application Server ; see the article in this issue of the journal).

Building multi-platform applications

The Delphi 6 package contains another component library, Borland Component Library for Cross-Platform (CLX), designed for use on both Windows and Linux (see the Borland Kylix article for details). Many of the CLX components and classes have the same names as their corresponding VCL components and classes, and have overlapping property, event, and method lists. CLX can be used to create source-compatible Kylix applications.

To create an application portable to Linux, select File | New | CLX application from the development environment menu. After that, the palette of components will change: it will display the components available in the CLX.

It should be borne in mind that today there are not many RAD tools that allow you to create multi-platform applications - especially those based on compilers.

Instead of a conclusion

The development of application building and data exchange technologies seems to be difficult to stop. If you ignore this fact, it will be difficult to survive in a competitive environment, especially for tool manufacturers.

We made sure that Delphi 6 is certainly an interesting and noteworthy product, and the innovations that are present in it mainly reflect the current trends in the development of the industry: this product has support for Web services, SOAP, XML data exchange, full CORBA support and even multi-platform support. Progress is clearly noticeable compared to the previous version, in which there were, perhaps, not so many innovations: ADO support, some changes in distributed computing technology, changes in COM support - and that's, actually, that's all ... to argue that the best results (from the point of view of the desire to purchase a product) are caused by the release of new versions more than once a year according to the calendar, as it was before, namely at the moment when new technologies, standards, platforms appear, which developers need support.

Nevertheless, it should be noted that not all modern technologies are yet supported in Delphi. For example, there is no hint of support for Microsoft .NET, and this is in a situation where the version of Delphi for Windows (an operating system created, as you know, by the same Microsoft company) remains one of the most popular and best-selling Borland products. Borland managers say they are just waiting for the appropriate operating system. Of course, they know better. And it is up to us to decide whether we are ready to wait with them.

ComputerPress 6 "2001

The BizSnap Web Services development platform simplifies the development and integration of business-to-business (B2B) applications by building Web Services based on SOAP / XML standards and providing interconnection tools to integrate the product manufacturer's business with the business of its suppliers and customers. companies.

The WebSnap Web Application Development Platform provides development speed, efficiency, and reliability.

The DataSnap platform enables developers to create high-performance, multi-tier solutions that access data through middle-tier software that can be integrated with any of your business partners' applications.

BizSnap
Providing Web Services Integration

Delphi BizSnap is a powerful Web Services development platform. BizSnap simplifies the exchange, transformation, and manipulation of XML documents, making your business applications flexible and extensible for the next wave of e-business. Delphi fully complies with industry standards, which means it can adequately respond to the rapidly changing requirements of modern business. Delphi allows you to work closely with the various applications of your channel partners using platforms such as .Net and BizTalk from Micorsoft, ONE from Sun Microsystems.

WebSnap
Accelerate Web Application Development

WebSnap is a complete web application development platform for Delphi using the most advanced Rapid Application Development (RAD) tools. Tools included with WebSnap, such as the debug Web server, make it easier to debug and test applications. The ability to tightly integrate WebSnap applications into corporate Web sites, portals developed using well-known tools such as DreamWeaver and FrontPage, as well as support for server-side scripting in JavaScript, VBScript, and other languages \u200b\u200ballow you to leverage existing Web application developments.

DataSnap
Providing Web-Enabled Mid-Range Application Development

Delphi DataSnap leverages all existing distributed data processing standards such as SOAP, XML, COM, CORBA and TCP / IP tools to simplify the integration of existing systems with new e-business applications. These standards allow Delphi applications to interact with any business process or Web service from your partners. DataSnap provides high-performance access to database management systems such as DB2, Informix, InterBase, MS SQL Server, Oracle and Sybase.

DataSnap optimizes the number of connections and data flows between clients and database servers by centralizing data access and updates among all e-business processes and applications, and also allows applications to scale based on changes in the amount of data processed.

Name: Delphi 6 - Object Pascal Programming.

The book is a guide to programming in the Delphi 6 environment. It covers the entire process of creating a program: from developing an algorithm and a dialog box to debugging and creating a help system. The material includes a number of topics that, as a rule, remain outside the scope of books addressed to novice programmers: processing symbolic information, using dynamic structures, working with files, creating a help system. The issues of working with graphics, multimedia and databases are considered. The description of the animation creation process in Macromedia Flash 5, the creation of the help system using the Microsoft HTML Help Workshop program is given.
The book is notable for the ease of presentation, a large number of illustrative examples and is addressed to students, high school students and all those studying programming in an educational institution or on their own. The accompanying diskette contains examples of the programs in the book.

Content
Foreword
Delphi - what is it?
About this book
Introduction
Beginning of work
First project
The form
Components
Event and event procedure
Code editor
Hint system
reference system
Project structure
Saving the project
Compilation
Errors
Warnings and hints
Running the program
Runtime errors
Alteration
Final application setup
Creating a unique icon for the application
Transferring an application to another computer
Chapter 1. Basics of programming
Program
Stages of program development
Determining program requirements
Algorithm development
Coding
Debugging
Testing
Algorithm and program
Compilation
Object Pascal programming language
Data type
Integer type
Real type
Character type
String type
Boolean type
Variable
Constants
Numeric constants
String and character constants
Boolean constants
Named constant
Assignment statement
Expression
Expression type
Executing an assignment statement
Standard functions
Arithmetic functions
Type conversion functions
Using functions
Data input
Input from the input window
Input from edit field
Output of results
Output to the message box
Output to a dialog box field
Procedures and functions
Procedure structure
Function structure
Recording program instructions
Programming style
Chapter 2. Object Pascal Control Structures
Condition
Choice
IF statement
CASE statement
Cycles
FOR statement
WHILE statement
REPEAT statement
GOTO instruction
Chapter 3. Symbols and strings
String Characters
String operations
LENGTH function
DELETE procedure
POS function
COPY function
Chapter 4. Console application
Instructions WRITE WRITELN
READ and READLN instructions
Creating a console application
Chapter 5. Arrays
Array declaration
Array operations
Array output
Array input
Using the StringGrid component
Using the Memo component
Finding the minimum (maximum) element of an array.
Searching an array for a given element
Simple search algorithm
Binary search method
Sorting an array
Sorting by direct selection
Sort by exchange method
Multidimensional arrays
Errors when using arrays
Chapter 6. Procedures and functions
Function
Function declaration
Using the function
Procedure
Procedure declaration
Using the procedure
Reuse of functions and procedures
Module creation
Using the module
Chapter 7. Files
File declaration
File purpose
Output to file
Opening a file for output
File open errors
Closing the file
Sample program
Input from file
Opening a file
Reading data from a file
Reading numbers
Reading lines
End of file detection
Chapter 8. Programmer-defined data types
Enumerated type
Interval type
Recording
Record announcement
WITH statement
Input and output of records to a file
Outputting a record to a file
Record input from file
Dynamic data structures
Pointers
Dynamic variables
Ordered list
Adding an item to the list
Removing an item from the list
Chapter 9. Introduction to Object Oriented Programming
Class
An object
Method
Encapsulation and Object Properties
Inheritance
Protected and Private Directives
Polymorphism and virtual methods
Delphi Classes and Objects
Chapter 10. Delphi graphics capabilities
Canvas
Pencil and brush
Pencil
Brush
Text output
Methods for drawing graphic primitives
Line
Broken line
Circle and ellipse
Arc
Rectangle
Polygon
Sector
Dot
Displaying illustrations
Bitmaps
Animation
Base point method
Using bitmaps
Loading a bitmap from a program resource
Creating a resource file
Connecting a resource file Viewing "cartoon"
Chapter 11. Delphi multimedia capabilities
Animate component
MediaPlayer component
Play sound
Sound recording
Watching videos and animations
Animation creation
Chapter 12. Recursion The concept of recursion Program examples
File search
Hilbert curve
Finding a way
Finding the shortest path
Chapter 13. Debugging a program
Error classification
Preventing and Handling Errors
Debugger
Trace the program
Program breakpoints
Adding a breakpoint
Changing breakpoint characteristics
Removing a breakpoint
Observing variable values
Chapter 14. reference system
Help Document File
Help system creation
Using the help system
Html
Help
Workshop
Preparation of reference information
Using Microsoft Word Editor
Using HTML Help Workshop
Create a help file
Compilation
Displaying help information
Chapter 15. Sample programs
Knowledge Testing System
Requirements for the program
Test file
Application form
Illustration output
Load test file
Program text
Improvement of the program
Minesweeper game 2001
rules
Data presentation
Application form
Beginning of the game
A game
reference Information
Information about the program
Listings
Chapter 16. Programmer component
Choosing a base class
Creating a component module
Component module testing
Installing a component
Component resources
Installation
Component installation errors
Component testing
Removing a component
Customizing the component palette
Chapter 17. Databases Database classification
Local database
Remote database
Database structure
Database Model in Delphi
Database alias
Database creation
Directory creation
Create an alias
Creating a table
Database management program
Access to the data file (table)
Database browsing
Form mode
Table mode Fetching information from a database Dynamically created aliases
Transferring the database management program to another computer
Conclusion
Appendix 1. Pascal language (quick reference)
Reserved words and directives
Module structure
Basic data types
Strings
Array
Recording
Selection instructions
If statement
Case statement
Cycles
For statement
Repeat statement
While statement
Unconditional jump
GoTo instruction
Function declaration
Procedure declaration
Standard functions and procedures
Appendix 2. Windows character encoding
Appendix 3. Presentation of information in a computer
Decimal and binary numbers
computer memory
Appendix 4. Recommended Further Reading
Appendix 5. Floppy disk description
Subject index

If you want to develop applications faster than in Visual Basic, and at the same time not approach the problem too complex, as in C ++, then Delphi is just for you.

Borland continues to develop, and here is the new Delphi 6 package. It is the fastest Windows developer and application builder, and now supports all of the most common WEB features and servers. With Delphi 6, individual or corporate users can create next generation e-business packages and applications quickly and easily.
Delphi 6 is a powerful, highly productive application development tool. He helps to complete any project in the shortest possible time. This application builder provides you with powerful, state-of-the-art, standardized utilities to control and refine your business data.
Delphi 6 now provides Linux compatibility, and supports database programming for Access, DB2, Dbase, FoxPro, InterBase, Informix, MS SQL, MySQL, MyBase, Oracle, Paradox, and Sybase.
Delphi 6 has new features and changes in the following areas: IDE, Internet, XML, Compiler, COM / Active X, Database support, CORBA, Actions, Custom Variants, VCL units and features, RTL units and features, Cross-platform development, Translation tools, Deployment changes, Help system extensibility.
However, some changes are not available in separate versions of Delphi 6.
Let's consider what features the integrated development environment Delphi 6 Enterprise Edition has.
After starting Delphi, the following windows will open in front of you (Figure 1).
You can see that a new element has appeared above the object inspector - this is the Object TreeView. Located in the top-left corner of the IDE, the TreeView is a tree diagram that shows the logical relationship between visual and non-visual components on a form.
The TreeView is synchronized with the Object Inspector and the Form Designer so that if you select a component and change it in any of the three tools (Form, Object Inspector, or TreeView object), the changes are reflected in the other two tools.
The TreeView object has some characteristics, let's look at them. It's located above the Object Inspector, and if you've hidden it, it appears when you press Alt + Shift + F11 or select View | Object TreeView.
The TreeView object displays both visual and non-visual components.
The toolbar includes a delete command and up and down buttons that work for the composite properties of components. For example, if you added a dataset component, you can select a value from a population.
Additionally, each component placed on the form is represented by its own image, for example, the parent component or child component, visual component or non-visual component are displayed differently (Figure 2).
If you activate a component in the Object TreeView, then it is activated on the form and the Object Inspector.
A right-click opens a pop-up menu with editing commands, the position of the component on the form (front or background), hiding the Object TreeView, etc. (Figure 3).
The Code Editor window has a standard page with an embedded Code Explorer window. In addition, there is an additional Diagram page.
The Charts page in the Code Editor provides visual tools for creating a chart to show relationships among visual and non-visual components. A diagram is a documentation tool that illustrates relationships in a diagrammatic manner and allows you to add comments to the diagram. Components do not appear on the Diagrams page until you drag them from the Object TreeView (Figure 4).
You can select many components from the TreeView and drag them onto the Charts page at the same time.
The left side of the Charts page has an editing element where you can type a title and description for each chart you create. At the top, there is a combo box to move to the next diagram.
At the top of the page is a Toolbar of buttons for connecting the blocks you place to create a diagram.
You can create a chart for each data module, forms that are added to your project.

It is one of the most successful products in Borland's line of IDEs (which began as Borland Delphi and is currently 10.1 Berlin). The program is intended primarily for developing applications in the client-server architecture. The main modules Delphi 7 produces are .exe and .dll. The visual design environment of the program takes on many routine functions for preparing the application. By doing this, it speeds up the creation time of the application and improves its quality. In many respects, the Borland C ++ Builder product has similar parameters, but instead of Pascal, it uses the C ++ language.

Delphi advantages and disadvantages

Application development time is much lower than when working in similar programs;
+ high performance in a compact volume;
+ the created application has minimum requirements for PC resources;
+ the ability to build the capacity of the program through plug-in modules;
+ as well as the ability to create such modules in the Delphi environment itself;
+ harmonious hierarchy of objects;
- the large size of some of the final applications and programs;
- impossibility to use other standard UI;
- lack of flexibility and originality: for any program executed in Delphi, one can understand that it is executed in Delphi.

Key features

• creation of applications and application programs in the Delphi language;
• launching and debugging programs in Delphi language;
• creation of cross-platform reports Rave Reports;
• work in the modeling environment ModelMaker;
• development of WEB-applications;
• editing, debugging and launching WEB applications;
• visualization, integration and reengineering;
• built-in manuals for basic functions;
• the ability to use ready-made design patterns;
• using the modules.exe and.dll.