Here is an example:<\/p>\n
\r\n\/\/ foo.private.h\r\n#pragma once\r\n\r\npartial ref class foo \/\/ <- here the partial keyword is used\r\n{\r\nprivate:\r\n int _id;\r\n Platform::String^ _name;\r\n};\r\n<\/pre>\n\r\n\/\/ foo.public.h\r\n#pragma once\r\n#include \"foo.private.h\"\r\n\r\nref class foo \/\/ <- partial keyword is not used here\r\n{\r\npublic:\r\n int GetId();\r\n Platform::String^ GetName();\r\n};\r\n<\/pre>\n\r\n\/\/ foo.cpp\r\n#include \"pch.h\"\r\n#include \"foo.public.h\"\r\n\r\nint foo::GetId() {return _id;}\r\nPlatform::String^ foo::GetName {return _name;}\r\n<\/pre>\nWhat happens when you add a new page to a C++ Metro style application? The wizard generates three files: a XAML file and a header and cpp file as the code behind. Let's say the page is called MainPage. In this case the three files are MainPage.xaml (code below is a dummy example), MainPage.xaml.h and MainPage.xaml.cpp.<\/p>\n
\r\n<UserControl x:Class=\"DemoApp.MainPage\"\r\n xmlns=\"http:\/\/schemas.microsoft.com\/winfx\/2006\/xaml\/presentation\"\r\n xmlns:x=\"http:\/\/schemas.microsoft.com\/winfx\/2006\/xaml\"\r\n xmlns:d=\"http:\/\/schemas.microsoft.com\/expression\/blend\/2008\"\r\n xmlns:mc=\"http:\/\/schemas.openxmlformats.org\/markup-compatibility\/2006\"\r\n mc:Ignorable=\"d\"\r\n d:DesignHeight=\"768\" d:DesignWidth=\"1366\">\r\n\r\n <StackPanel Name=\"firstPanel\">\r\n <Button Name=\"firstButon\" \/>\r\n <\/StackPanel>\r\n \r\n<\/UserControl>\r\n<\/pre>\n\r\n\/\/\r\n\/\/ MainPage.xaml.h\r\n\/\/ Declaration of the MainPage.xaml class.\r\n\/\/\r\n\r\n#pragma once\r\n\r\n#include \"pch.h\"\r\n#include \"MainPage.g.h\"\r\n\r\nnamespace DemoApp\r\n{\r\n public ref class MainPage\r\n {\r\n public:\r\n MainPage();\r\n ~MainPage();\r\n };\r\n}\r\n<\/pre>\n\r\n\/\/\r\n\/\/ MainPage.xaml.cpp\r\n\/\/ Implementation of the MainPage.xaml class.\r\n\/\/\r\n\r\n#include \"pch.h\"\r\n#include \"MainPage.xaml.h\"\r\n\r\nusing namespace Windows::UI::Xaml;\r\nusing namespace Windows::UI::Xaml::Controls;\r\nusing namespace Windows::UI::Xaml::Data;\r\nusing namespace DemoApp;\r\n\r\nMainPage::MainPage()\r\n{\r\n InitializeComponent();\r\n}\r\n\r\nMainPage::~MainPage()\r\n{\r\n}\r\n<\/pre>\nYou can notice that the objects firstPanel<\/em> and firstButton<\/em> are not defined in the header for MainPage and second, MainPage.xaml.h includes MainPage.g.h. So what is this? This is a designer generated file, which together with MainPage.g.cpp completes the definition of the MainPage ref class. These files are not generated until you start a build. After you do that you can find them in the output folder (Debug or Release for instance). This is how they look:<\/p>\n\r\n#pragma once\r\n\/\/------------------------------------------------------------------------------\r\n\/\/ This code was generated by a tool.\r\n\/\/\r\n\/\/ Changes to this file may cause incorrect behavior and will be lost if\r\n\/\/ the code is regenerated.\r\n\/\/------------------------------------------------------------------------------\r\n\r\nnamespace Windows {\r\n namespace UI {\r\n namespace Xaml {\r\n namespace Controls {\r\n ref class StackPanel;\r\n ref class Button;\r\n }\r\n }\r\n }\r\n}\r\n\r\nnamespace DemoApp\r\n{\r\n partial ref class MainPage : public Windows::UI::Xaml::Controls::UserControl, \r\n public Windows::UI::Xaml::Markup::IComponentConnector\r\n {\r\n public:\r\n void InitializeComponent();\r\n void Connect(int connectionId, Platform::Object^ pTarget);\r\n\r\n private:\r\n Windows::UI::Xaml::Controls::StackPanel^ firstPanel;\r\n Windows::UI::Xaml::Controls::Button^ firstButon;\r\n };\r\n}\r\n<\/pre>\n\r\n\/\/------------------------------------------------------------------------------\r\n\/\/ This code was generated by a tool.\r\n\/\/\r\n\/\/ Changes to this file may cause incorrect behavior and will be lost if\r\n\/\/ the code is regenerated.\r\n\/\/------------------------------------------------------------------------------\r\n#include \"pch.h\"\r\n\r\n#include \"MainPage.xaml.h\"\r\n\r\n\r\nusing namespace Windows::Foundation;\r\nusing namespace Windows::UI::Xaml;\r\nusing namespace Windows::UI::Xaml::Controls;\r\nusing namespace Windows::UI::Xaml::Markup;\r\nusing namespace MyDemoApplication1;\r\n\r\nvoid MainPage::InitializeComponent()\r\n{\r\n \/\/ Call LoadComponent on ms-resource:\/\/DemoApp\/Files\/MainPage.xaml\r\n Windows::UI::Xaml::Application::LoadComponent(this, ref new Windows::Foundation::Uri(\"ms-resource:\/\/DemoApp\/Files\/MainPage.xaml\"));\r\n\r\n \/\/ Get the StackPanel named 'firstPanel'\r\n firstPanel = safe_cast<Windows::UI::Xaml::Controls::StackPanel^>(static_cast<IFrameworkElement^>(this)->FindName(\"firstPanel\"));\r\n\r\n \/\/ Get the Button named 'firstButon'\r\n firstButon = safe_cast<Windows::UI::Xaml::Controls::Button^>(static_cast<IFrameworkElement^>(this)->FindName(\"firstButon\"));\r\n\r\n}\r\n\r\nvoid MainPage::Connect(int connectionId, Platform::Object^ pTarget)\r\n{\r\n}\r\n<\/pre>\nThe following image illustrates the grouping of these files:
\n![\"\"](\"\/blog\/wp-content\/uploads\/2011\/10\/cpppartialclass.png\" "\\"C++\/CX")
\nMainPage.xaml is a XAML files, which can be edited both by the designer or manually by the developer (basically with the designer is still the developer that models the UI). The other files are C++\/CX files. MainPage.xaml.h and MainPage.xaml.cpp are the files the developer writes, while MainPage.g.h and MainPage.g.cpp are edited by the designer. Do not modify the code in these files, because you could either mess up the designer, or all your changes would get lost when the file is regenerated.<\/p>\n