.DelegateTo not available any longer In Spring4D?

[Pio Pio]

Hello,

Another question, sorry. Am I wrong or the construct "Container.RegisterType<IMyInterface, TMyClass>.DelegateTo(" is not available any longer.

If so what this is replaced with ?

Many thanks

Alberto

[Adam Siwoń]

You could use:

Container.RegisterType<TMyClass>(ActivatorDelegate).Implements<IMyInterface>;

[Anders Gustavsson]

Not needed at all. Just put the function there! 

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[Alberto Paganini]

Hi Both and thank you for your answer, firstly.

Hi Anders,

If I use Container.RegisterType<TMyClass>; how can I link TMyClass to IMyInterface?

Hi Adam,

I have amended ActivatorDelegate into TActivatorDelegate but I get the following error

Container.RegisterType<TMyClass>(TActivatorDelegate).Implements<IMyInterface>;

[DCC Error] uRegistrations.pas(106): E2232 Interface 'TActivatorDelegate' has no interface identification

Where am I doing wrong here?

Many thanks

Alberto

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[Adam Siwoń]

Hi,

I have no idea what is wrong in your code. Here is small example which works in my code:

type
  IMyInterface = interface(IInvokable)
    ['{419BF7C5-A87F-4FC9-AB37-2D475B1A5E6D}']
    procedure Test;
  end;

  TMyClass = class(TInterfacedObject, IMyInterface)
  public
    procedure Test;
  end;

procedure TMyClass.Test;
begin
end;

function Create_TMyClass: TMyClass;
begin
  Result := TMyClass.Create;
end;

procedure RegisterInContainer;
begin
  GlobalContainer.RegisterType<TMyClass>(Create_TMyClass).Implements<IMyInterface>;
  GlobalContainer.Build;
end;

[Anders Gustavsson]

Container.RegisterType<IMyIntetface, TMyClass>

.function: TMyClass 

begin 

  Result :=.... 

end;

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[Dominik Vorreiter]

Stefan Glienke answered it here: https://groups.google.com/g/spring4d/c/AHG1Et8rWgw

You can pass the delegate directly to the RegisterType<>() function as an argument.

[Pio Pio]

Hello everybody and thanks for your answers.

What if I had the following construct

  Container.RegisterType<IMyInterface, TMyClass>('ABC')(
    function:  TMyClass
    begin
      result :=  TMyClass.Create
    end);

What is the new syntax?

Many thanks again

Alberto

[Pio Pio]

Hello,

I made a few attempts  and  the following code compiles:

Container.RegisterType<IMyInterface, TMyClass>('ABC').AsCustom(

function: TMyClass
begin
result := TMyClass.Create
end
);

but, is it correct?

Many thanks

Alberto

[Pio Pio]

Hello,

One more step.

I have updated the syntax of the several Container.RegisterType I have in the registration file as per my previous message and the application compiles.

I ran it and I got the error message "EcontainerException Container has changed registration information - Build required" when the second RegisterType was executed.
At this stage, I have added Container.Build after the first RegisterType and that was the source

procedure RegisterTypes(Container: TContainer);
begin
  Container.RegisterType<IMyFirstInterface, TMyFirstClass>(
    function: TMyFirstClass
    begin
      result := TMyFirstClass.Create(nil);
    end).AsSingleton(TRefCounting.True);

  Container.Build;
  Container.RegisterType<IMySecondIterface, TMySecondClass>('ABC').AsCustom(TMySecondClass.Create(nil, Container.Resolve
    <IMyFirstInterface>)).AsSingleton; //EIntfCastError Interface not supported

  ...
end;

this time I have a "EIntfCastError Interface not supported" error message when the application tries to execute the second RegisterType

The following is the Interface declaration:
  IMainDM = interface
    ['{CA5F2949-F634-40A6-8E82-222F52FB4B5D}']
    methods....
  end;


What else should I change to progress now?

Many thanks
Alberto

[Stefan Glienke]

The code you provide in the activator callback is completely pointless because that is what the container does.

Providing such a callback is only necessary if the container will not be able to construct the instance because it is fetched some something ouf of control for the container.

[Pio Pio]

Hello,

I have looked again into all the suggestions and realised what everybody was telling me. I have amended the registration of all the classes with the following syntax and it works now:

  IMyFirstInterface = interface
    ['{1179C0D0-F340-43C2-A004-970F466CA513}']
//methods
  end;
  IMySecondInterface = interface
    ['{654076DA-377D-45DF-9A5F-E571E58AE116}']
//methods
  end;

  TMyFirstClass = class(TInterfacedObject, IMyFirstInterface)
    // methods
  end;
  TMySecondClass = class(TInterfacedObject, IMySecondInterface)
    // methods
  end;

  procedure RegisterInContainer;
  begin
    GlobalContainer.RegisterType<TMyFirstClass>(
function: TMyFirstClass
    begin
      result := TMyFirstClass.Create;
    end).Implements<IMyFirstInterface>;

    GlobalContainer.RegisterType<TMySecondClass>(
    function: TMySecondClass
    begin
      result := TMySecondClass.Create(Container.Resolve<IMyFirstInterface>);
    end).Implements<IMySecondInterface>('ABC');

...
GlobalContainer.Build;
  end;



Thank you very much to everyone!

[Stefan Glienke]

The use of the activator callbacks is unnecessary. The container knows how to call constructors.

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[Dr Kristau]

I'm still confused as to the syntax to replace .DelegateTo in the case of constructor injection, as in the example here.

What can I use to replace these calls?

  GlobalContainer.RegisterType<string>('name').DelegateTo(
                                   function: string
                                   begin
                                     Result := GetLocalUsername;
                                   end
                                   );
  GlobalContainer.RegisterType<string>('occupation').DelegateTo(
                                   function: string
                                   begin
                                     Result := 'plumber';
                                   end
                                   );

  GlobalContainer.RegisterType<integer>('age').DelegateTo(
                                   function: integer
                                   begin
                                     Result := Random(100);
                                   end
                                   );

Thank you!

[Stefan Glienke]

You pass the delegate as the first parameter to RegisterType.