RTTI и атрибуты

// Проследите фактическое поведение RttiVisibility.
program RttiVisibility;
{$APPTYPE CONSOLE}
uses System.Rtti;
type
  TSample = class
  private
    FHidden: Integer;
  published
    property Visible: Integer read FHidden write FHidden;
  end;
var
  Ctx: TRttiContext;
  Prop: TRttiProperty;
begin
  Ctx := TRttiContext.Create;
  try
    Prop := Ctx.GetType(TSample).GetProperty('Hidden');
    if Assigned(Prop) then
      Writeln(Prop.Name)
    else
      Writeln('missing');
  finally
    Ctx.Free;
  end;
end.

// Определите реальную гарантию в RttiIntegration.
program RttiIntegration;
{$APPTYPE CONSOLE}
uses System.Rtti, System.SysUtils;
function ReadProperty(Instance: TObject; const Name: string): TValue;
var
  Ctx: TRttiContext;
  P: TRttiProperty;
begin
  Ctx := TRttiContext.Create;
  try
    P := Ctx.GetType(Instance.ClassType).GetProperty(Name);
    if not Assigned(P) then
      raise EPropertyError.CreateFmt('Property %s is absent', [Name]);
    Result := P.GetValue(Instance);
  finally
    Ctx.Free;
  end;
end;
begin end.

// Отделите правило языка от удачного запуска RttiCache.
program RttiCache;
{$APPTYPE CONSOLE}
uses System.Rtti;
type
  TSample = class
  private
    FName: string;
  published
    property Name: string read FName write FName;
  end;
var
  Ctx: TRttiContext;
  Prop: TRttiProperty;
  I: Integer;
begin
  Ctx := TRttiContext.Create;
  try
    for I := 1 to 100000 do
      Prop := Ctx.GetType(TSample).GetProperty('Name');
    Writeln(Prop.Name);
  finally
    Ctx.Free;
  end;
end.

// Отделите правило языка от удачного запуска TValueInvoke.
program TValueInvoke;
{$APPTYPE CONSOLE}
uses System.Rtti;
type
  TCalc = class
    function Add(A, B: Integer): Integer;
  end;
function TCalc.Add(A, B: Integer): Integer;
begin
  Result := A + B;
end;
var
  Ctx: TRttiContext;
  M: TRttiMethod;
  Obj: TCalc;
begin
  Ctx := TRttiContext.Create;
  try
    Obj := TCalc.Create;
    try
      M := Ctx.GetType(TCalc).GetMethod('Add');
      Writeln(M.Invoke(Obj, [1, '2']).AsInteger);
    finally
      Obj.Free;
    end;
  finally
    Ctx.Free;
  end;
end.

// Отделите правило языка от удачного запуска AttributeMetadata.
program AttributeMetadata;
{$APPTYPE CONSOLE}
uses System.Rtti;
type
  RequiredAttribute = class(TCustomAttribute);
  TModel = class
  private
    FName: string;
  published
    [Required]
    property Name: string read FName write FName;
  end;
begin end.