Delphi使用RTTI获取属性的默认值
it1352
帮助1人
问题说明
如果我有这样的类：
TServerSettings = class(TSettings)
strict private
FHTTPPort : Integer;
published
property HTTPPort : Integer read FHTTPPort write FHTTPPort default 80;
end;
如何获取默认值属性使用RTTI的 HTTPPort 属性
How can I get the default attribute of the HTTPPort property using RTTI?
正确答案
#1
像这样：
{$APPTYPE CONSOLE}
uses
System.TypInfo;
type
TMyClass = class
strict private
FMyValue: Integer;
published
property MyValue: Integer read FMyValue default 42;
end;
var
obj: TMyClass;
PropInfo: PPropInfo;
begin
obj := TMyClass.Create;
PropInfo := GetPropInfo(obj, 'MyValue');
Writeln(PropInfo.Default);
end.
请注意，像它一样的类，就像你的问题一样，是坏的。创建实例时，系统不会自动将属性初始化为其默认值。您需要为此类添加一个构造函数。
Note that the class as it stands, just as is so for that in your question, is broken. The system will not automatically initialise properties to their default value when an instance is created. You would need to add a constructor to this class to do that.
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