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using System;
using System.Runtime.InteropServices;

namespace NAddIn
{
    [ClassInterface(ClassInterfaceType.AutoDual)]
    public class Functions
    {
        public Functions()
        {
        }
        
        public double Add2(double v1, double v2)
        {
            return v1 + v2;
        }

        [ComRegisterFunctionAttribute]
        public static void RegisterFunction(System.Type t)
            

        {
            Microsoft.Win32.Registry.CurrentUser.CreateSubKey(
                "CLSID\\{" + t.GUID.ToString().ToUpper() + "}\\Programmable");
        }

        [ComUnregisterFunctionAttribute]
        public static void UnregisterFunction(System.Type t)
        {
            Microsoft.Win32.Registry.CurrentUser.DeleteSubKey(
                "CLSID\\{" + t.GUID.ToString().ToUpper() + "}\\Programmable");
        }
    }
}					

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using System;
using System.Runtime.InteropServices;
using Microsoft.Win32;
using System.IO;

namespace NAddIn
{
    [ClassInterface(ClassInterfaceType.AutoDual)]
    public class Functions
    {
        public Functions()
        {
        }
        
        public double Adddbl(double v1, double v2)
        {
            return v1 + v2;
        }

        [ComRegisterFunctionAttribute]
        public static void RegisterFunction(System.Type t)
        {
            string guidPath = String.Format("CLSID\\{{{0}}}", t.GUID.ToString().ToUpper());
            string mscoreePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.System), "mscoree.dll");
            string inprocServer32Path = String.Format("{0}\\{1}", guidPath, "InprocServer32");
            string programmablePath = String.Format("{0}\\{1}", guidPath, "Programmable");

            RegistryKey key = Registry.ClassesRoot.OpenSubKey(inprocServer32Path, true);

            key.SetValue("", mscoreePath);

            Registry.ClassesRoot.CreateSubKey(programmablePath);
        }
        [ComUnregisterFunctionAttribute]
        public static void UnregisterFunction(System.Type t)
        {
            string guidPath = String.Format("CLSID\\{{{0}}}", t.GUID.ToString().ToUpper());
            string inprocServer32Path = String.Format("{0}\\{1}", guidPath, "InprocServer32");
            string programmablePath = String.Format("{0}\\{1}", guidPath, "Programmable");

            RegistryKey key = Registry.ClassesRoot.OpenSubKey(inprocServer32Path, true);
            key.SetValue(String.Empty, string.Empty);

            Registry.ClassesRoot.DeleteSubKey(programmablePath);
        }

    }
}