{"id":1882,"date":"2015-01-28T04:46:38","date_gmt":"2015-01-27T20:46:38","guid":{"rendered":"http:\/\/blog.qdac.cc\/?p=1882"},"modified":"2015-01-28T17:37:06","modified_gmt":"2015-01-28T09:37:06","slug":"qstring-%e4%b8%ad%e6%99%ba%e8%83%bd%e6%8c%87%e9%92%88%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/blog.qdac.cc\/?p=1882","title":{"rendered":"QString \u4e2d\u667a\u80fd\u6307\u9488\u5b9e\u73b0"},"content":{"rendered":"<p>\u5728 Delphi \u4e2d\u8981\u5b9e\u73b0\u667a\u80fd\u6307\u9488\uff0c\u5b9e\u9645\u4e0a\u662f\u4e00\u4e2a\u633a\u9ebb\u70e6\u7684\u4e8b\u3002QString.pas \u5355\u5143\u7684 TQPtr \u5c01\u88c5\u4e86\u4e00\u4e2a\u667a\u80fd\u6307\u9488\u7684\u5b9e\u73b0\uff0c\u5b83\u548c\u4e00\u822c\u7684\u667a\u80fd\u6307\u9488\u5b9e\u73b0\u4e00\u6837\uff0c\u5229\u7528\u4e86\u63a5\u53e3\u7684\u81ea\u52a8\u7ba1\u7406\u7279\u6027\u3002\u6211\u4eec\u5148\u770b\u4e00\u4e0b\u5b83\u7684\u58f0\u660e\uff1a<\/p>\n<pre class=\"lang:delphi decode:true \">  IQPtr = interface(IInterface)\r\n    function Get: Pointer;\r\n  end;\r\n\r\n  TQPtrFreeEvent=procedure (AData:Pointer) of object;\r\n  TQPtrFreeEventG=procedure (AData:Pointer);\r\n  {$IFDEF UNICODE}\r\n  TQPtrFreeEventA=reference to procedure (AData:Pointer);\r\n  {$ENDIF}\r\n  TQPtr = class(TInterfacedObject, IQPtr)\r\n  private\r\n    FObject: Pointer;\r\n    FOnFree:TQPtrFreeEvent;\r\n    {$IFDEF UNICODE}\r\n    FOnFreeA:TQPtrFreeEventA;\r\n    {$ENDIF}\r\n  public\r\n    constructor Create(AObject: Pointer); overload;\r\n    destructor Destroy; override;\r\n    class function Bind(AObject: TObject): IQPtr;overload;\r\n    class function Bind(AData:Pointer;AOnFree:TQPtrFreeEvent):IQPtr;overload;\r\n    class function Bind(AData:Pointer;AOnFree:TQPtrFreeEventG):IQPtr;overload;\r\n    {$IFDEF UNICODE}\r\n    class function Bind(AData:Pointer;AOnFree:TQPtrFreeEventA):IQPtr;overload;\r\n    {$ENDIF}\r\n    function Get: Pointer;\r\n  end;<\/pre>\n<p>\u5728\u8fd9\u91cc\uff0c\u6211\u4eec\u4e3b\u8981\u7528\u5229\u7528\u5176\u4e2d\u7684\u7c7b\u51fd\u6570 Bind \u6765\u5b8c\u6210\u5bf9\u8c61\u6216\u5176\u5b83\u7c7b\u578b\u7684\u6307\u9488\u5230\u63a5\u53e3\u7684\u5c01\u88c5\u3002<\/p>\n<p>TQPtr \u5185\u90e8\u5b9e\u73b0\u4e86\u5bf9 TObject \u7c7b\u578b\u7684\u81ea\u52a8\u91ca\u653e\u5904\u7406\uff0c\u4f46\u5bf9\u4e8e\u7ed3\u6784\u4f53\u6216\u8005\u8bf4\u662f\u8bb0\u5f55\uff0c\u7531\u4e8e\u590d\u6742\u7684\u7ed3\u6784\u4f53\u5305\u542b\u4e86\u6210\u5458\u7684\u91ca\u653e\u7b49\u989d\u5916\u7684\u64cd\u4f5c\uff0c\u800c\u7ed3\u6784\u4f53\u4e5f\u6ca1\u6709\u6790\u6784\u51fd\u6570\u6765\u5b8c\u6210\u8fd9\u4e00\u5207\uff0c\u6240\u4ee5\u9700\u8981\u63d0\u4f9b\u4e00\u4e2a\u91ca\u653e\u51fd\u6570\u6765\u51b3\u5b9a\u5982\u4f55\u91ca\u653e\u8fd9\u4e2a\u6307\u9488\u6307\u5411\u7684\u6570\u636e\u3002\u8fd9\u91cc\u6709\u4e09\u4e2a\u91cd\u8f7d\u5206\u522b\u5bf9\u5e94\u7c7b\u6210\u5458\u51fd\u6570\u3001\u5168\u5c40\u51fd\u6570\u548c\u533f\u540d\u51fd\u6570\u7248\u672c\uff0c\u6211\u4eec\u4ee5\u5176\u4e2d\u4e00\u4e2a\u7248\u672c\u4e3a\u4f8b\u6765\u6f14\u793a\u8fd9\u4e00\u70b9\u3002<\/p>\n<p>\u9996\u5148\uff0c\u8c03\u7528 TQPtr.Bind \u6765\u8fd4\u56de\u4e00\u4e2a IQPtr \u63a5\u53e3\uff0c\u5bf9\u4e8e\u7c7b\u7684\u5b9e\u4f8b AObject\uff0c\u6211\u4eec\u53ea\u9700\u8981\u5982\u4e0b\u4ee3\u7801\u5373\u53ef\uff1a<\/p>\n<pre class=\"lang:delphi decode:true\">var\r\n  IObj:IQPtr;\r\nbeegin\r\nIObj:=TQPtr.Bind(AObject);\r\nend;<\/pre>\n<p>\u5bf9\u4e8e\u8bb0\u5f55\u7c7b\u578b\u6307\u9488 MyRecordPtr \uff08\u5047\u8bbe\u7c7b\u578b\u662f PMyRecord\uff09\uff0c\u6211\u4eec\u9700\u8981\u63d0\u4f9b\u4e00\u4e2a\u91ca\u653e\u51fd\u6570\uff1a<\/p>\n<pre class=\"lang:delphi decode:true \">var\r\n IRec:IQPtr;\r\nbegin\r\nIRec:=TQPtr.Bind(MyRecordPtr,\r\n  procedure (AData:Pointer)\r\n  begin\r\n  Dispose(PMyRecord(AData));\r\n  end);\r\nend;<\/pre>\n<p>\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5728\u4f7f\u7528\u65f6\uff0c\u600e\u4e48\u5c06\u5b83\u8f6c\u6362\u56de\u5bf9\u8c61\u6216\u8bb0\u5f55\u6307\u9488\u5462\uff1f\u5047\u8bbe\u6211\u4eec\u5c06\u4e0a\u9762\u7684IObj\u7ed9\u4e00\u4e2a\u51fd\u6570 Foo \u505a\u4e3a\u53c2\u6570\uff1a<\/p>\n<pre class=\"lang:delphi decode:true \">function Foo(IObj:IQPtr);\r\nvar\r\n  AObj:TObject;\r\nbegin\r\nAObj:=IObj.Get;\r\n...\r\nend;\r\n<\/pre>\n<p>\u5bf9\u4e8e\u8bb0\u5f55\uff0c\u6211\u4eec\u8bb0\u5f55\u7684\u4ee3\u7801\u548c\u4e0a\u9762\u51e0\u4e4e\u6ca1\u6709\u533a\u522b\uff1a<\/p>\n<pre class=\"lang:delphi decode:true \">function Foo(IRec:IQPtr);\r\nvar\r\n  ARec:PMyRecord;\r\nbegin\r\nARec:=IRec.Get;\r\n...\r\nend;<\/pre>\n<p>OK\uff0c\u8fd9\u5c31\u662f QString \u63d0\u4f9b\u7684\u667a\u80fd\u6307\u9488\u5c01\u88c5\u7684\u5b9e\u73b0\u3002<\/p>\n<p>\u6709\u4eba\u5bfb\u6c42\u57fa\u4e8e\u6cdb\u578b\u7684\u667a\u80fd\u6307\u9488\u5b9e\u73b0\uff0c\u5b9e\u9645\u4e0a\u57fa\u4e8e\u6cdb\u578b\u4e0d\u662f\u4e0d\u53ef\u4ee5\uff0c\u4f46\u5c31\u53ea\u80fd\u5bf9\u5bf9\u8c61\u8fdb\u884c\u7ba1\u7406\u4e86\uff0c\u800c\u4e0a\u9762\u53ef\u4ee5\u5bf9\u7ed3\u6784\u6216\u5176\u5b83\u81ea\u5df1\u5206\u914d\u7684\u6307\u9488\u8fdb\u884c\u7ba1\u7406\u3002<\/p>\n<p>\u4e0b\u9762\u63d0\u4f9b\u4e00\u4e2a\u57fa\u4e8e\u6cdb\u578b\u7684\u7b80\u5355\u5b9e\u73b0\uff1a<\/p>\n<pre class=\"lang:delphi decode:true\">...\r\n  ISmartPtr&lt;PType:class&gt;=interface\r\n    function Get:PType;\r\n  end;\r\n  TSmartPtr&lt;PType:class&gt;=class(TInterfacedObject,ISmartPtr&lt;PType&gt;)\r\n  protected\r\n    FObject:PType;\r\n  public\r\n    constructor Create(AObj:PType);overload;\r\n    destructor Destroy;override;\r\n    function Get:PType;\r\n  end;\r\n...\r\n{ TSmartPtr&lt;PType&gt; }\r\n\r\nconstructor TSmartPtr&lt;PType&gt;.Create(AObj: PType);\r\nbegin\r\ninherited Create;\r\nFObject:=AObj;\r\nend;\r\n\r\ndestructor TSmartPtr&lt;PType&gt;.Destroy;\r\nbegin\r\nif Assigned(FObject) then\r\n  FreeAndNil(FObject);\r\ninherited;\r\nend;\r\n\r\nfunction TSmartPtr&lt;PType&gt;.Get: PType;\r\nbegin\r\nResult:=FObject;\r\nend;<\/pre>\n<p>\u8fd9\u6837\u5c31\u662f\u5f3a\u7c7b\u578b\u7684\u4e86\uff0c\u7528\u6cd5\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n<pre class=\"lang:delphi decode:true\">var\r\n  IList:ISmartPtr&lt;TStringList&gt;;\r\nbegin\r\nIList:=TSmartPtr&lt;TStringList&gt;.Create(TStringList.Create);\r\nIList.Get.Add('Hello,world');\r\nend;\r\n<\/pre>\n<p>\u5404\u53d6\u6240\u9700\u5427\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728 Delphi \u4e2d\u8981\u5b9e\u73b0\u667a\u80fd\u6307\u9488\uff0c\u5b9e\u9645 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[8,9,21],"tags":[305],"class_list":["post-1882","post","type-post","status-publish","format-standard","hentry","category-delphi","category-qdac","category-misc","tag-305"],"views":4641,"_links":{"self":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/1882","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1882"}],"version-history":[{"count":4,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/1882\/revisions"}],"predecessor-version":[{"id":1887,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/1882\/revisions\/1887"}],"wp:attachment":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1882"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1882"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1882"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}