'member' : must be a member of serializable class or struct; 'class/struct' is not marked as __serializable
For a member to be marked as __transient, the class must be marked as __serializable.
The following sample generates C3256:
#using<mscorlib.dll> __gc class X { // The follow line resolves the error. // __gc __serializable class X { __transient int A; // C3256 }; void main() { };