How to: Upcast with safe_cast
An upcast is a cast from a derived type to one of its base classes. This cast is safe and does not require an explicit cast notation. The following sample shows how to perform an upcast with safe_cast and without it.
Example
// safe_upcast.cpp
// compile with: /clr
using namespace System;
interface class A {
void Test();
};
ref struct B : public A {
virtual void Test() {
Console::WriteLine("in B::Test");
}
void Test2() {
Console::WriteLine("in B::Test2");
}
};
ref struct C : public B {
virtual void Test() override {
Console::WriteLine("in C::Test");
};
};
int main() {
C ^ c = gcnew C;
// implicit upcast
B ^ b = c;
b->Test();
b->Test2();
// upcast with safe_cast
b = nullptr;
b = safe_cast<B^>(c);
b->Test();
b->Test2();
}
in C::Test in B::Test2 in C::Test in B::Test2