Version Issues for Value Types Nested in Native Types (C++/CLI)

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Consider a signed (strong name) assembly component used to build a client assembly. The component contains a value type that is used in the client as the type for a member of a native union, a class, or an array. If a future version of the component changes the size or layout of the value type, the client must be recompiled.

Create a keyfile with sn.exe (sn -k mykey.snk).

Example

The following sample is the component.

// nested_value_types.cpp  
// compile with: /clr /LD  
using namespace System::Reflection;  
[assembly:AssemblyVersion("1.0.0.*"),   
assembly:AssemblyKeyFile("mykey.snk")];  
  
public value struct S {  
   int i;  
   void Test() {  
      System::Console::WriteLine("S.i = {0}", i);  
   }  
};  

Example

This sample is the client:

// nested_value_types_2.cpp  
// compile with: /clr  
#using <nested_value_types.dll>  
  
struct S2 {  
   S MyS1, MyS2;  
};  
  
int main() {  
   S2 MyS2a, MyS2b;  
   MyS2a.MyS1.i = 5;  
   MyS2a.MyS2.i = 6;  
   MyS2b.MyS1.i = 10;  
   MyS2b.MyS2.i = 11;  
  
   MyS2a.MyS1.Test();  
   MyS2a.MyS2.Test();  
   MyS2b.MyS1.Test();  
   MyS2b.MyS2.Test();  
}  

Output

S.i = 5  
S.i = 6  
S.i = 10  
S.i = 11  

Comments

However, if you add another member to struct S in nested_value_types.cpp, (for example, double d;) and recompile the component without recompiling the client, the result is an unhandled exception (of type System.IO.FileLoadException).

See Also

Managed Types (C++/CLI)