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 (C# Reference) and as (C# Reference).

Example

// 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

See Also

Other Resources

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