Firing events from a unmanaged function

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C++/CLI

unmanaged

I am trying to fire an event from a unmanaged function using a pointer to managed object

I get the following error.
error C3767: 'ShashiTest::test::OnShowResult::raise': candidate function(s) not accessible
How ever I can call regular function ShowMessage without any issue.

#pragma once
	#using<mscorlib.dll>
	#using<system.windows.forms.dll> 

	using namespace System;
	using namespace System::ComponentModel;
	using namespace System::Collections;
	using namespace System::Diagnostics;
	using namespace System::Windows::Forms;

	namespace ShashiTest {

		public delegate void ShowResult(System::String^);
		public ref class test
		{
			
		public:
			event ShowResult^ OnShowResult;
			test(void)
			{		
				
			};
			void ShowMessage()
			{
				MessageBox::Show("Hello World");
			}
			

		};
		class ManagedInterface
		{
		public:
			gcroot<test^> m_test;
			ManagedInterface(){};
			~ManagedInterface(){};	

			void ResultWindowUpdate(std::string ResultString);

		};
	}
	void ShashiTest::ManagedInterface::ResultWindowUpdate(std::string ResultString)
	{
		if(m_test)
		{
			System::String ^result = gcnew system::String(ResultString.c_str());
			m_test->OnShowResult(result);
		}
	}</system.windows.forms.dll></mscorlib.dll>