XML Schema Reader Writer Plugin for VS 2005/2008

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration.Install;
using System.IO;
using System.Xml;


namespace PostInstaller
{
    [RunInstaller(true)]
    public partial class PostInstaller : Installer
    {
        public PostInstaller()
        {
            InitializeComponent();
            this.BeforeUninstall += new InstallEventHandler(PostInstaller_BeforeUninstall);
        }

        void PostInstaller_BeforeUninstall(object sender, InstallEventArgs e)
        {
            string vsCfgInstallPath = GetVsAddInPath("8.0");
            if( vsCfgInstallPath != null )
            {
                if (File.Exists(vsCfgInstallPath))
                    File.Delete(vsCfgInstallPath);
            }

            vsCfgInstallPath = GetVsAddInPath("9.0");
            if (vsCfgInstallPath != null)
            {
                if (File.Exists(vsCfgInstallPath))
                    File.Delete(vsCfgInstallPath);
            }
        }

     
        public override void Install(IDictionary savedState)
        {
            System.Diagnostics.Process[] process = System.Diagnostics.Process.GetProcessesByName("devenv");
            if( null != process && process.Length > 0)
                throw new InstallException("Instance of visual studio was detected, all instances must be closed before installation");

            if (null == GetVsAddInPath("9.0") && null == GetVsAddInPath("8.0") )
                throw new InstallException("Visual studio 2005/ 2008 installation wasn't found");
                
            base.Install(savedState);

            // get the source directory of the installation from the default context parameters
            string TheAssemblyPath = this.Context.Parameters["assemblypath"];
            TheAssemblyPath = Path.GetDirectoryName(TheAssemblyPath) + Path.DirectorySeparatorChar;

            SavePluginCfgFile(TheAssemblyPath);
        }


        static string GetVsAddInPath(string vsVersion)
        {
            string regKey = string.Format(@"HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\{0}", vsVersion);
            string vsCfgPath = (string)Microsoft.Win32.Registry.GetValue(regKey, "VisualStudioLocation", null);

            if (vsCfgPath == null) return null;//VS not installed

            
            vsCfgPath = vsCfgPath + Path.DirectorySeparatorChar + "Addins";
            if (!Directory.Exists(vsCfgPath))
                Directory.CreateDirectory(vsCfgPath);
            
            vsCfgPath += Path.DirectorySeparatorChar + "XmlSchemaAddon.AddIn";
            return vsCfgPath;
        }

        static void SavePluginCfgFile(string installPath)
        {
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load( new MemoryStream(Properties.Resources.XmlSchemaAddon) );
            string strValue = xmlDoc.DocumentElement["Addin"]["Assembly"].InnerText;
            xmlDoc.DocumentElement["Addin"]["Assembly"].InnerText = installPath + strValue;

            //saving as VS 2008 plugin

            string cfgFilePath = GetVsAddInPath("9.0");
            if (null != cfgFilePath )
            {
                foreach (XmlElement child in xmlDoc.DocumentElement.ChildNodes)
                {
                    if (child == null || 0 != string.Compare(child.Name, "HostApplication", true))
                        continue;

                    child["Version"].InnerText = "9.0";
                }
                xmlDoc.Save(cfgFilePath);
            }                  

            //saving as VS 2005 plugin

            cfgFilePath = GetVsAddInPath("8.0");
            if( null != cfgFilePath )
            {
                foreach (XmlElement child in xmlDoc.DocumentElement.ChildNodes)
                {
                    if (child == null || 0 != string.Compare(child.Name, "HostApplication", true))
                        continue;

                    child["Version"].InnerText = "8.0";
                }
                xmlDoc.Save(cfgFilePath);
            }            
        }
    }


   
}