获取/设置使用RTTI的子属性 [英] Get/Set sub properties ussing RTTI

问题描述

鉴于以下代码片段，使用 GetPropValue（MyComponent，'MySubComponent.Prop1'）引发了EPropertyError异常。
如何使用GetPropValue / SetPropValue检索或设置SubProperties的值？

Given the following code snippet below, using GetPropValue(MyComponent,'MySubComponent.Prop1') raises an EPropertyError exception. How can I retrieve or set the values of SubProperties using GetPropValue / SetPropValue?

Type
  TMySubComponent = class(TInterfacedPersitent)
  private
    FProp1: Integer;
  published
    property Prop1: integer read FProp1 write FProp1;
  end;

  TMyComponent = class(TCompoent)
  private
    FMySubComponent : TMySubcomponent; 
  published
    property MySubComponent: TMySubComponent read FMySubComponent write FMySubComponent ;
  end;

推荐答案

不支持您在问题中使用的点符号

The dot notation you used in your question is not supported.

您需要获取SubComponent的值，然后对各个属性执行Set和Get。

You need to get the Value of the SubComponent, then perform the Set and Get on the individual properties.

var
  C: TRttiContext;
  MyComp : TMyComponent;
  MyCompType : TRttiInstanceType;
  MySubCompType : TRttiInstanceType;
  MySubComponentValue : TValue;
begin
  MyComp := TMyComponent.create(Self); 
  ...
  // RTTI.Pas Method
  MyCompType :=  c.GetType(TMyComponent.ClassInfo) as TRttiInstanceType;
  MySubCompType := c.GetType(TMySubComponent.ClassInfo) as TRttiInstanceType;
  MySubComponentValue := MyCompType.GetProperty('MySubComponent').GetValue(MyComp);

  if Not MySubComponentValue.IsEmpty then
  begin
      MySubCompType.GetProperty('Prop1').SetValue(MySubComponentValue.AsObject,43);
  end;

 //TypInfo.pas Method
 SubComp := GetObjectProp(MyComp,'MySubComponent');
 if Assigned(SubComp) then
 begin
    SetPropValue(SubComp,'Prop1',5);
    prop1Value := GetPropValue(SubComp,'Prop1');
 end;

end;

TypInfo.pas方法仅适用于已发布的属性，您可以使用RTTI获取公共属性.pas方法。

The TypInfo.pas method will only work with published properties, you can get the public properties with the RTTI.pas method.

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