RttiMethod Invoke (invalid class typecast)

[Davide Visconti 5]

type
  TMyClass = class
  public
    procedure Run;
  end;

  TMyTool = class
  public
    MyClass: TMyClass;
    constructor Create;
  end;

...
var
  MyTool: TMyTool;

procedure TFrmMain.FormCreate(Sender: TObject);
begin
  MyTool := TMyTool.Create;
end;
procedure TFrmMain.Btn1Click(Sender: TObject);
var
  LCtx             : TRttiContext;
  LType1           : TRttiType;
  LField1          : TRttiField;
  LNestedType1     : TRttiType;
  LRttiInstanceType: TRttiInstanceType;
  LMeth            : TRttiMethod;
begin
  LCtx         := TRttiContext.Create;
  LType1       := LCtx.GetType(MyTool.ClassType);
  LField1      := LType1.GetField('MyClass');
  LNestedType1 := LCtx.GetType(LField1.FieldType.Handle);
  LMeth        := LNestedType1.GetMethod('Run');
  // LMeth.Invoke(MyTool.MyClass, []);  		// <-- ok
  LMeth.Invoke(LNestedType1.AsInstance, []);	// <-- fail
end;

 

I get "invalid class typecast" I understand where is the problem but I don't know how to resolve it.

I have to call the method "MyClass.Run" through RTTI.

Can you help me please?

Any suggestion will be appreciated.

Thank you.

 

 

[Davide Visconti 5]

This work.

Do you have any suggestions?

procedure TFrmMain.Btn1Click(Sender: TObject);
var
  LCtx             : TRttiContext;
  LType1           : TRttiType;
  LField1          : TRttiField;
  LNestedType1     : TRttiType;
  LRttiInstanceType: TRttiInstanceType;
  LMeth            : TRttiMethod;
  LObj             : TObject;
begin
  LCtx         := TRttiContext.Create;
  LType1       := LCtx.GetType(MyTool.ClassType);
  LField1      := LType1.GetField('MyClass');
  LObj         := LField1.GetValue(MyTool).AsObject;
  LNestedType1 := LCtx.GetType(LField1.FieldType.Handle);
  LMeth        := LNestedType1.GetMethod('Run');
  // LMeth.Invoke(MyTool.MyClass, []); // ok
  // LMeth.Invoke(LNestedType1.AsInstance.ClassInfo, []); // fail
  LMeth.Invoke(LObj, []);
end;

 

[Kryvich 165]

procedure Run is a method of object, not a class method. So you need an object instance to call the method.

[Davide Visconti 5]

Yes of course.

Thanks @Kryvich