本講題將對C++/CLI做一個概觀性的介紹。 在C++/CLI之前，.NET平台上的C++開發方案，多半只能選擇採用Managed C++。無可諱言的，Managed C++本身存在一些改善的空間，諸如：語法的優雅與寫作的流暢、對泛型程式設計的支援等等。然而，在著名的C++語言大師Stan Lippman及Herb Shtter加入VC++的團隊中時，重新制定後的C++/CLI卻讓這些問題得到了解決的方案。在Visual Studio 2005中，完全支援C++標準的C++/CLI加入了新語法及語義，針對.NET環境提供了最直接的支援。 有了C++/CLI，原先標準的C++能力不僅不會受損，而C++/CLI中的標準擴充，也使得C++在.NET平台上獲得額外的加持。C++/CLI有了.NET的加持，一舉具備了reflection及垃圾回收的能力。.NET所提供的標準類別庫，也都可為其所用。再加上C++/CLI混合了unmanaged及managed兩種執行環境，更使得C++/CLI具備更多效率的空間，同時能夠開發系統層級的應用程式。 有了C++/CLI，在.NET平台上的C++程式員如同取得一把新的寶劍。

1. C++/CLI 概觀 王建興 qing@cs.nthu.edu.tw (Email/MSN) 2007/1/25

4. 在 C++/CLI 出現前， .NET 上的 C++ 程式員恐怕只有一個字可以形容 悶

8. 好消息是… .Net 上的 C++ 程式員不用再悶了

12. C++/CLI 的目標就是 無接縫式的整合 Unmanaged 及 Managed Code

15. C++ 與 CTS 型別的對應 N/A Boolean bool N/A Double long double N/A Double double N/A Single float UInt64 Int64 __int64 UInt32 Int32 long int UInt32 Int32 int, __int32 UInt16 Int16 short int Byte Sbyte char CTS Unsigned Type CTS Signed Type C++ Type

21. 不同的兩種物件生成及運用模式 *Kate Gregory, “Moving C++ Applications to the Common Language Runtime”   Use Native Heap    Use Managed Heap   Use Stack ^ and % always * and & never Verifiability d elete delete Free gcnew new Allocate % & Reference ^ * Pointer / Handle Managed Native

25. Tracking Reference 的效應 array<String^>^ arr = gcnew array<String^>(3); int i = 0; for each(String^% s in arr) s = gcnew String(i++.ToString()); for each(String^ s in arr) Console::WriteLine(s); 執行結果： 0 1 2 array<String^>^ arr = gcnew array<String^>(3); int i = 0; for each(String^ s in arr) s = gcnew String(i++.ToString()); for each(String^ s in arr) Console::WriteLine(s); 執行結果：

30. Why SuppressFinalize? public class FileStream : Stream { public override void Close() { // Clean up this object: flush data and close file … // There is no reason to Finalize this object now GC.SuppressFinalize(this); } protected override void Finalize() { Close(); // Clean up this object: flush data and close file } // Rest of FileStream methods go here … } *http://www.codeproject.com/managedcpp/cppclidtors.asp 如果程式員自行呼叫了 Close() ， 但 GC 又呼叫了 Finalize() 便會引發 Close() 被叫用兩次

31. 自動進行的 Disposal { SqlConnection conn(connString); } constructor 會被呼叫 destructor 會被自動呼叫 { SqlConnection ^pConn = gcnew SqlConnection(connString); } constructor 會被呼叫 之後就要等待 GC 動作了

34. 陣列的初始化 array<String^>^ strarr = gcnew array<String^> {“String1&quot;, “String2&quot;}; array<String^>^ strarr2 = {“String1&quot;, “String2&quot;}; array<Object^,2> ^ objarr = {{“String1&quot;, 1}, {“String2&quot;, 2}};

36. Property 的語法 ref class UserAccount { public: property String^ ID { String^ get(){return id;} virtual void set(String^ value){id = value;} } private: String^ id; }; 就和 C# 的定義方式類似

37. Index Property 的語法 ref class OnlineUserList{ public: property UserAccount^ User[int] { UserAccount^ get(int idx){return (UserAccount^) alUser[idx];} } OnlineUserList() { alUser = gcnew System::Collections::ArrayList(); } // … private: System::Collections::ArrayList ^alUser; };

38. Refernece Type 允許單一繼承多重實作 ref class R abstract {}; public ref class R2 : R, IClone, IComparable, IDisposable, IEnumerable { }; 所有 reference type 都繼承自 System::Object 最多繼承一個類別，但可以實作多個介面

39. Exception Handling try { throw gcnew Exception(&quot;qing&quot;); } catch(System::Exception^ e) { Console::WriteLine(e->StackTrace); }

41. 在 VS 2005 中選擇編譯模式

42. 編譯模式之間的關連性 Native CLR Code Data Machine Code CLR Data / Types Native Data / Types MSIL Code Mixed C++ /clr Native C++ Verifiable C++ /clr:safe Pure C++ /clr:pure

44. 決定 Managed/Unmanaged 的交界處 C++ managed C++ CRT, STL, etc One call to foo() Hundreds of calls C# or C++ managed C++ CRT, STL, etc One call to foo() Hundreds of calls C# C++ CRT, STL, etc Hundreds of calls C++ One call to foo() One call * Kate Gregory, “ Moving C++ Applications to the Common Language Runtime”

45. C++/CLI 支援 Template template<typename T1, typename T2> class NativeData { public: NativeData(T1 t1) { m_t1 = t1; } void DoStuff(T2 t2) { //... } private: T1 m_t1; }; *http://www.codeproject.com/managedcpp/cppcligenerics.asp

46. Tempalte 採用 Lazy Constraint (1/2) template<typename T> class Native { public: void Start(int x) { T* t = new T(); t->Bark(x); t->WagTail(); delete t; } }; 如何確定 t 有 Bark() 及 WagTail() 兩 methods 呢？ *http://www.codeproject.com/managedcpp/cppcligenerics.asp

47. Tempalte 採用 Lazy Constraint (2/2) Native<NativeDog> d1; d1.Start(100); Native<NativePig> d2; d2.Start(100); 引發編譯器錯誤： error C2039: 'Bark' : is not a member of 'NativePig' *http://www.codeproject.com/managedcpp/cppcligenerics.asp

48. C++/CLI 支援 Generics generic<typename T1, typename T2> ref class GenericData { public: GenericData(T1 t1) { m_t1 = t1; } void DoStuff(T2 t2) { //... } private: T1 m_t1; }; *http://www.codeproject.com/managedcpp/cppcligenerics.asp

49. Generics 採用 Subtype Constraints (1/3) generic<typename T> where T:IDog ref class GenRef { public: void Start(int x) { T t = Activator::CreateInstance<T>(); t->Bark(x); t->WagTail(); delete safe_cast<Object^>(t); } }; 透過限制 T 必須實作的介面來進行約束 *http://www.codeproject.com/managedcpp/cppcligenerics.asp

50. Generics 採用 Subtype Constraints (2/3) ref class ClrDog : IDog { public: virtual void Bark(int Loudness) { Console::WriteLine(&quot;ClrDog::Bark {0}&quot;,Loudness); } virtual void WagTail() { Console::WriteLine(&quot;ClrDog::WagTail&quot;); } }; *http://www.codeproject.com/managedcpp/cppcligenerics.asp

51. Generics 採用 Subtype Constraints (3/3) GenRef<ClrDog^> g1; g1.Start(100); *http://www.codeproject.com/managedcpp/cppcligenerics.asp

52. 使用 Reference Types 於 Template template<typename T> class CLR { public: void Start(int x) { T^ t = gcnew T(); t->Bark(x); t->WagTail(); delete t; } }; CLR<ClrDog> g2; g2.Start(100)

53. 將 Template 宣告為 Reference Type template<typename T> ref class CLR2 { public: void Start(int x) { T^ t = gcnew T(); t->Bark(x); t->WagTail(); delete t; } }; CLR 2 <ClrDog> g 3 ; g 3 .Start(100) Console::WriteLine(g3.GetType()->Name); 執行結果： ClrDog::Bark 100 ClrDog::WagTail CLR2<ClrDog>

54. Generics Functions generic<typename T> where T:IDog void DoAll(T t) { t->Bark(0); t->WagTail(); } *http://www.codeproject.com/managedcpp/cppcligenerics.asp

60. Thanks