//工具启动路径
  string toolPath = System.Windows.Forms.Application.StartupPath + "\\邮件小工具.exe";

  string extension = SptdConst.FileExtension;

  string fileType = "Email File";

  string fileContent = "text/plain";
  //获取信息
  Microsoft.Win32.RegistryKey registryKey = Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(extension);

  if (registryKey != null && registryKey.OpenSubKey("shell") != null && registryKey.OpenSubKey("shell").OpenSubKey("open") != null &&
    registryKey.OpenSubKey("shell").OpenSubKey("open").OpenSubKey("command") != null)
  {
    var varSub = registryKey.OpenSubKey("shell").OpenSubKey("open").OpenSubKey("command");
    var varValue = varSub.GetValue("");

    if (Object.Equals(varValue, toolPath + " %1"))
    {
      return;
    }
  }
  //删除
  Microsoft.Win32.Registry.ClassesRoot.DeleteSubKeyTree(extension, false);
  //文件注册
  registryKey = Microsoft.Win32.Registry.ClassesRoot.CreateSubKey(extension);
  registryKey.SetValue("文件类型", fileType);
  registryKey.SetValue("Content Type", fileContent);
  //设置默认图标
  Microsoft.Win32.RegistryKey iconKey = registryKey.CreateSubKey("DefaultIcon");
  iconKey.SetValue("", System.Windows.Forms.Application.StartupPath + "\\logo.ico");
  //设置默认打开程序路径
  registryKey = registryKey.CreateSubKey("shell\\open\\command");
  registryKey.SetValue("", toolPath + " %1");
  //关闭
  registryKey.Close();

//双击启动打开
 //如果原有路径中存在空格，则会分解成多个元素
if (e.Args.Length > 0)
{
   string filePath = String.Join(" ", e.Args.ToArray());
   FileInfo file = new FileInfo(filePath);
   if (file.Exists)
    {
      EmailToolConst.DoubleClickSptdFilePath = file.FullName;
    }
 }