Jump to content

Search the Community

Showing results for tags 'class'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Delphi Questions and Answers
    • Algorithms, Data Structures and Class Design
    • VCL
    • FMX
    • RTL and Delphi Object Pascal
    • Databases
    • Network, Cloud and Web
    • Windows API
    • Cross-platform
    • Delphi IDE and APIs
    • General Help
    • Delphi Third-Party
  • C++Builder Questions and Answers
    • General Help
  • General Discussions
    • Embarcadero Lounge
    • Tips / Blogs / Tutorials / Videos
    • Job Opportunities / Coder for Hire
    • I made this
  • Software Development
    • Project Planning and -Management
    • Software Testing and Quality Assurance
  • Community
    • Community Management

Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


Delphi-Version

Found 2 results

  1. Hi there, here are the steps that lead to the problem: 1. from the IDE, create a "console application" 2. from MMX code explorer, click on the "Add Class" button, and add the proposed class 3. state the class is added at the wrong place in the IDE editor (cf attached picture)
  2. Hi, I'm experimenting some interface design and came up with the following: I would like to query a BaseClass instance if it supports a given interface, without freeing the class! As the example below, my great grand child class can support an interface, but I don't want to include the class definition ( great grand child class ) in the Base class.. So, by defining interfaces, I can write exactly what I want: TMyFrame = Class( TBaseFrame, {SupportedInterfaces}) In the code below procedure TForm22.Button1Click(Sender: TObject); begin if Supports( fBaseFrameClass, ISupportTask ) then (fBaseFrame as ISupportTask).CheckTask; end; No matter what overload Support method I call, fBaseFrame is freed once the method exits. Is there a way to know if my class instance supports an interface and call the corresponding method without messing ref counting and free the class instance prematurely? unit frm.main; interface uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls; type ISupportTask = Interface ['{3F785F20-7C44-4163-B55C-5EA267C7204E}'] function CheckTask : Boolean; end; ISupportList = Interface ['{9B7D95E1-DA96-475A-9A1C-910CAF99E5F5}'] function ListCount : Integer; End; ISupportItem = Interface ['{ACADFA2F-3500-4ACB-8049-F49FAC38EFB2}'] function SaveItem : Boolean; End; TBaseFrame = Class( TInterfacedObject ) protected fDummy : Boolean; End; TBaseFrameClass = Class of TBaseFrame; TMyFrame = Class( TBaseFrame, ISupportTask, ISupportList, ISupportItem ) public function CheckTask : Boolean; function ListCount : Integer; function SaveItem : Boolean; destructor Destroy; override; End; TForm22 = class(TForm) Button1: TButton; procedure Button1Click(Sender: TObject); procedure FormCreate(Sender: TObject); procedure FormDestroy(Sender: TObject); private { Private declarations } fBaseFrameClass : TBaseFrameClass; fBaseFrame : TBaseFrame; public { Public declarations } end; var Form22: TForm22; implementation {$R *.dfm} procedure TForm22.Button1Click(Sender: TObject); begin if Supports( fBaseFrameClass, ISupportTask ) then (fBaseFrame as ISupportTask).CheckTask; end; { TMyFrame } function TMyFrame.CheckTask: Boolean; begin Result := True; end; destructor TMyFrame.Destroy; begin fDummy := True; inherited; end; function TMyFrame.ListCount: Integer; begin Result := 42; end; function TMyFrame.SaveItem: Boolean; begin Result := False; end; procedure TForm22.FormCreate(Sender: TObject); begin fBaseFrameClass := TMyFrame; fBaseFrame := fBaseFrameClass.Create; end; procedure TForm22.FormDestroy(Sender: TObject); begin fBaseFrame.Free; end; end.
×