public void AddFiles(params string[] files)
        {
            foreach (var file in files)
            {
                var job = new SignJobViewModel(file);
                if (job.IsInvalid)
                {
                    continue;
                }

                job.Close = new RelayCommand(x => Jobs.Remove(job), x=>!job.IsBusy);
                job.Sign = new RelayCommand(x =>
                            {
                                Task.Factory
                                    .StartNew(() =>
                                    {
                                        Thread.Sleep(50);
                                        job.State = SignJobState.Signing;
                                        DocumentSigner.For(job.FileType).Sign(job.InputFile, job.OutputFile, ActiveCert);
                                    })
                                    .ContinueWith(task =>
                                    {
                                        job.Error = task.Exception.InnerException.Message;
                                        job.State = SignJobState.Failed;
                                    }, TaskContinuationOptions.OnlyOnFaulted)
                                    .ContinueWith(task => job.State = SignJobState.Signed, TaskContinuationOptions.OnlyOnRanToCompletion);
                            }, x => job.IsReady && ActiveCert != null);
                Jobs.Add(job);
                //if (job.IsReady)
                //{
                //    job.Sign.Execute(null);
                //}
            }
        }
        public void AddFiles(params string[] files)
        {
            foreach (var file in files)
            {
                var job = new SignJobViewModel(file);
                if (job.IsInvalid)
                {
                    //TODO:explain why, don't just fail so silently
                    continue;
                }
                job.Close = new RelayCommand(x => Jobs.Remove(job));
                job.Sign = new RelayCommand(x =>
                {
                    var cert = ActiveCert;
                    if (cert != null)
                    {
                        var signTask = Task.Factory.StartNew(() =>
                        {
                            job.State = SignJobState.Signing;
                            job.OutputFile = GetOutputNameSafe(job.InputFileName);
                            DocumentSigner.For(job.FileType)
                                          .Sign(job.InputFile, job.OutputFile, cert);
                        });

                        signTask.ContinueWith(task =>
                        {
                            job.Error = task.Exception.InnerException.Message;
                            job.State = SignJobState.Failed;
                        }, TaskContinuationOptions.OnlyOnFaulted);

                        signTask.ContinueWith(task =>
                        {
                            job.State = SignJobState.Signed;
                        }, TaskContinuationOptions.OnlyOnRanToCompletion);
                    }
                });

                Jobs.Add(job);
                if (job.IsReady)
                {
                    job.Sign.Execute(null);
                }
            }
        }