扫描所有类对于给定的自定义属性 [英] Scan all classes for a given custom attribute

问题描述

我在寻找扫描所有加载的类包含自定义属性，如果可能的话类的方式，不使用的RegisterClass（）。

I'm looking for a way of scanning all loaded classes for classes which contain a custom attribute, if possible, without using RegisterClass().

推荐答案

首先，你必须创建 TRttiContext ，然后用得到所有加载的类 getTypes 。后，您可以通过 TypeKind = tkClass 过滤器类型;
下一步是枚举属性，并检查是否有您的属性;

at first you have to create TRttiContext, then get all loaded classes using getTypes. after that you can filter types by TypeKind = tkClass; next step is to enumerate attributes and check if it has your attribute;

属性和测试类delcaration：

attribute and test-class delcaration:

unit Unit3;

interface
type
    TMyAttribute = class(TCustomAttribute)
    end;

    [TMyAttribute]
    TTest = class(TObject)

    end;

implementation

initialization
    TTest.Create().Free();  //if class is not actually used it will not be compiled

end.

，然后找到它：

program Project3;
{$APPTYPE CONSOLE}

uses
  SysUtils, rtti, typinfo, unit3;

type TMyAttribute = class(TCustomAttribute)

     end;

var ctx : TRttiContext;
    t : TRttiType;
    attr : TCustomAttribute;
begin
    ctx := TRttiContext.Create();

    try
        for t  in ctx.GetTypes() do begin
            if t.TypeKind <> tkClass then continue;

            for attr in t.GetAttributes() do begin
                if attr is TMyAttribute then begin
                    writeln(t.QualifiedName);
                    break;
                end;
            end;
        end;
    finally
        ctx.Free();
        readln;
    end;
end.

输出 Unit3.TTest

通话的RegisterClass注册一类的流媒体系统....一旦类被注册，就可以装载或组件流媒体系统保存。

Call RegisterClass to register a class with the streaming system.... Once classes are registered, they can be loaded or saved by the component streaming system.

所以，如果你不需要的组件流的（只要找到一些属性类），没有必要的RegisterClass

so if you don't need component streaming (just find classes with some attribute), there is no need to RegisterClass

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