问Python4Delphi -用TPyDelphiWrapper.WrapInterface包装delphi接口中的错误
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Stack Overflow用户

提问于 2021-10-13 05:24:49

回答 1查看 270关注 0票数 0

我使用Python3.8和Delphi 10.4.2。

我正在尝试使用Python4Delphi的组件通过一个Python访问一些在Delphi中定义的接口。

在设计时，我将TPythonEngine、TPythonModule和TPyDelphiWrapper组件添加到项目的VCL表单中。

因此，我定义了3个接口，分别由3个类实现，如下所示

type
  IPerson = interface (IUnknown)
    ['{1D21B5B6-25DE-4884-8BDB-8E2D9A239D64}']
    function GetName : string;
    procedure SetName ( value : string );
    property Name: string read GetName write SetName;   
    function GetSurname: string;
    procedure SetSurname(value : string);
    property Surname : string read GetSurname write SetSurname;    
    function GetInfo : string;
  end;

  ICustomer = interface (IPerson)
    ['{8742364C-33E8-4FF4-86FB-C19AF67A735B}']
    function GetCustomerNumber : string;
    procedure SetCustomerNumber ( value : string );
    property CustomerNumber : string read GetCustomerNumber write SetCustomerNumber;
  end;

  ISupplier = interface ( IPerson )
    ['{420FFF78-92DE-4D7E-9958-FDA95748EEB7}']
    function GetSupplierNumber : string;
    procedure SetSupplierNumber ( value : string );
    property SupplierNumber : string read GetSupplierNumber write SetSupplierNumber;
  end;

  TPerson = class ( TInterfacedObject , IPerson)
  private
    FName : string;
    FSurname : string;    
    function GetName : string;
    procedure SetName ( value : string );    
    function GetSurname: string;
    procedure SetSurname(value : string);

  public
    property Surname : string read GetSurname write SetSurname;
    property Name: string read GetName write SetName;    
    function GetInfo : string; virtual;
  end;


  TCustomer = class ( TPerson , ICustomer)
  private
    FCustomerNumber : string;
    function GetCustomerNumber : string;
    procedure SetCustomerNumber ( value : string);

  public    
    property CustomerNumber : string read GetCustomerNumber write SetCustomerNumber;
    function GetInfo: string; override;
  end;


  TSupplier = class ( TPerson , ISupplier)
  private
    FSupplierNumber : string;
    function GetSupplierNumber : string;
    procedure SetSupplierNumber ( value : string );

  public
    property SupplierNumber : string read GetSupplierNumber write SetSupplierNumber;
    function GetInfo : string; override;
  end;

在表单的Create方法中，我定义了3个变量，每个变量对应3个接口，通过PyDelphiWrapper，我在3个不同的Python变量中将它们传递给Python模块。

procedure TFrmTestInterface.FormCreate(Sender: TObject);
var
  LPerson : IPerson;
  LCustomer : ICustomer;
  LSupplier : ISupplier;
  Py: PPyObject;
begin

  LPerson := TPerson.Create;
  LCustomer := TCustomer.Create;
  LSupplier := TSupplier.Create;

  LPerson.Name := 'Pippo';
  LPerson.Surname := 'Rossi';

  LCustomer.Name := 'Pluto';
  LCustomer.Surname := 'Verdi';

  LSupplier.Name := 'Paperino';
  LSupplier.Surname := 'Bianchi';


  Py := PyDelphiWrapper1.WrapInterface(TValue.From(LPerson));
  PythonModule1.SetVar('delphi_person', Py);
  GetPythonEngine.Py_DecRef(Py);

  Py := PyDelphiWrapper1.WrapInterface(TValue.From(LCustomer));
  PythonModule1.SetVar('delphi_customer', Py);
  GetPythonEngine.Py_DecRef(Py);

  Py := PyDelphiWrapper1.WrapInterface(TValue.From(LSupplier));
  PythonModule1.SetVar('delphi_supplier', Py);
  GetPythonEngine.Py_DecRef(Py);

end;

在运行时，变量被正确地解释，但是每次我试图访问接口中定义的属性之一时，我总是得到相同的错误。

这是我试图运行的Python脚本：

from delphi_module import delphi_person, delphi_customer, delphi_supplier 

print('type(delphi_person) = ', type(delphi_person)) 
print('type(delphi_customer) = ', type(delphi_customer)) 
print('type(delphi_supplier) = ', type(delphi_supplier)) 

print(delphi_person.Name)

我所犯的错误

回溯(最近一次调用)：AttributeError中的文件""，第7行:获取属性"Name“中的错误。错误:未知属性

类型(.)命令对这三个变量正确运行。

如果没有使用接口类型的3个变量，而是将每个变量声明为类类型，使用PyDelphiWrapper.Wrap方法，一切都可以正常工作！

procedure TFrmTestInterface.FormCreate(Sender: TObject);
var
  LPerson : IPerson;
  LCustomer : ICustomer;
  LSupplier : ISupplier;
  Py: PPyObject;
begin

  LPerson := TPerson.Create;
  LCustomer := TCustomer.Create;
  LSupplier := TSupplier.Create;

  LPerson.Name := 'Pippo';
  LPerson.Surname := 'Rossi';

  LCustomer.Name := 'Pluto';
  LCustomer.Surname := 'Verdi';

  LSupplier.Name := 'Paperino';
  LSupplier.Surname := 'Grandi';


  Py := PyDelphiWrapper1.Wrap(LPerson, TObjectOwnership.soReference);
  PythonModule1.SetVar('delphi_person', py);
  GetPythonEngine.Py_DECREF(py);

  Py := PyDelphiWrapper1.Wrap(LCustomer, TObjectOwnership.soReference);
  PythonModule1.SetVar('delphi_customer', py);
  GetPythonEngine.Py_DECREF(py);

  Py := PyDelphiWrapper1.Wrap(LSupplier, TObjectOwnership.soReference);
  PythonModule1.SetVar('delphi_supplier', py);
  GetPythonEngine.Py_DECREF(py);

end;