How to: Implement is and as C# Keywords (C++/CLI)

 

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The latest version of this topic can be found at How to: Implement is and as C# Keywords (C++/CLI).

This topic shows how to implement the functionality of the is and as C# keywords in Visual C++.

For more information, see is and as.

// CS_is_as.cpp  
// compile with: /clr  
using namespace System;  
  
interface class I {  
public:  
   void F();  
};  
  
ref struct C : public I {  
   virtual void F( void ) { }  
};  
  
template < class T, class U >   
Boolean isinst(U u) {  
   return dynamic_cast< T >(u) != nullptr;  
}  
  
int main() {  
   C ^ c = gcnew C();  
   I ^ i = safe_cast< I ^ >(c);   // is (maps to castclass in IL)  
   I ^ ii = dynamic_cast< I ^ >(c);   // as (maps to isinst in IL)  
  
   // simulate 'as':  
   Object ^ o = "f";  
   if ( isinst< String ^ >(o) )  
      Console::WriteLine("o is a string");  
}  

o is a string  

Interoperability with Other .NET Languages (C++/CLI)

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