BindAPI

BindAPI is a small framework for Delphi to bind virtually any property or field among classes without few code lines: just decorate your class with some attributes and run your app. You can use BindAPI with any library. See the Quick Guide for more detailed information.

Current version is 0.9.0.0 Alpha. Some improvements will be released in next weeks to obtain a more complete framework.

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Use

BindAPI is aimed to create prototypes, demo, POC and small applications.

You can bind any property method or field to a source just adding some attributes and registering involved classes.

unit fBindApiSimpleDemo;

interface

uses
  ...,
  plBindAPI.Attributes, plBindAPI.CoreBinder, plBindAPI.AutoBinder,
  plBindAPI.ClassFactory;
type
  {Bind an instance of this class to an instance of TTestController}
  [BindClass(True, 'TTestController')]
  {The value of the property edtSame.Text is read from TTestController.TestObject.IntProp}
  [BindMemberFrom('edtSame.Text', 'TestObject.IntProp')]
  {The following bind is disabled (first parameter is False)}  
  [BindMemberFrom(False, 'edtTarget2.Text', 'LowerText')]
  {Bind an instance of this class to an instance of TTestController and the value is converted by TTestController.DoubleOf}
  [BindMemberTo(True, 'speValue.Value', 'DoubleValue', 'DoubleOf')]
  {Bind the event btnTest.OnClick to the procedure TTestController.TestEventBind}
  [BindMethod(True, 'btnTest.OnClick', 'TestEventBind')]
  TfrmBindApiSimpleDemo = class(TForm)
    ...
    {The value of speValue.Value is sent to TTestController.TestObject.IntProp}
    [BindMemberTo('Value', 'TestObject.IntProp')]
    speValue: TSpinEdit;
    ...
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
 public
    {This form's property recives its value from TTestController.UpperText}
    [BindMemberFrom('.', 'UpperText')]
    property UpperText: string read GetUpperText write SetUpperText;
    {You can bind any property or field with two or more elements}
    [BindMemberTo(True, '.', 'NewValue')]
    [BindMemberTo('.', 'DoubleValue', 'DoubleOf')]
    property Value: Integer read GetValue write SetValue;
    ...

implementation

uses
  plBindAPI.BindManagement;

procedure TfrmBindApiSimpleDemo.FormCreate(Sender: TObject);
begin
  {Remember: if the bound class is not a singleton, the binder is
   responsible of its destruction}
  TplBindManager.Bind(Self);
end;

procedure TfrmBindApiSimpleDemo.FormDestroy(Sender: TObject);
begin
  TplBindManager.Unbind(Self);
end;

...

end.

The Business Logic is in another unit:

unit Test.Controller;

interface

uses
  ..., 
  plBindAPI.ClassFactory;

type

  TTestController = class(TInterfacedObject) {or any other class}
  public
    function DoubleOf(const NewValue, OldValue: TValue): TValue
  ... 
  end;

implementation
  function TTestController.DoubleOf(const NewValue, OldValue: TValue): TValue
  begin
    case NewValue.Kind of
      tkInteger:
        Result := NewValue.AsInteger * 2;
      tkInt64:
        Result := NewValue.AsInt64 * 2;
      tkFloat:
        Result := NewValue.AsType<Double> * 2
      else
        Result := 0;
    end;
  end;
  ...

initialization
  {Just add this line:}
  TplClassManager.RegisterClass(TTestController, [Singleton]);

That's all. You can also bind two elements manually. See demo and test apps for other examples.

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Features

• A small but effective set of attributes for binding.
• No need to rewrite existing libraries, just add attributes in your form and classes.
• Can bind almost any field, property and methods of a class supported by RTTI. At present, support for indexed properties is not complete.
• Support of qualified names.
• Compatible with MVC, MVP, MVVM - just select your source and target classes to implement your architecture.
• A couple of type conversion is automatically supported.
• You can use a function to test, convert or manipulate a value.

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New in 0.9.0.0 Beta version {#LastVersion}

• The 0.9.0.0 Beta version branch is the working branch from Dec. 19, 2024.
• Full support for indexed properties.
• New test cases.

New in 0.9.0.0 Alpha version

It is a full rewrite of 0.8 version in order to simplify the interface of attributes and objects

New features:

• Full code documentation
• A new set of live templates helps you enter attributes - just copy them in your code_templates\Delphi folder.
• The new static class TPlRTTIUtils contains some useful procedures and functions to work with RTTI.
• Better support for records
• Attributes can read indexed properties values (support for write them is wip)

Main Changes:

• Attributes was renamed in consistent way. See the [ChangeLog](.\Doc\Version 0.9 changes.md) for more information.

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Roadmap

• 0.9.0: complete test case for implemented methods.
• 0.9.1: More demo covering the full potential of BindAPI.
• 0.9.2: A message-based system to manage registered objects destruction.
• 0.9.3: First demo for Android.
• 0.9.4: Code optimization.
• 0.9.5: Visual tools for monitoring binding status.
• 0.9.6: Interfaces definition.
• 0.9.7: ...
• 0.9.8: ...
• 0.9.9: ...

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To be continued...

Future releases will include:

• Full support for collections and array
• Best support for records
• A bit of documentation (as soon as possible, of course)
• More and more test cases
• FreePascal support (as 3.x version with full support for RTTI will be released)
• Android support
• Better management of interval in thread, maybe introducing a timer
• Hopefully, a tool to create bound classes skeltons from attributes

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Warning

BindAPI has been tested only with Delphi 12.1 CE. BindAPI is a previerw release and under active development. Although it is quite mature, it requires more and more tests before any use in real production environments.