Document approval workflow system

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using DocumentBaseLibrary;
using DocumentCore.Bll;
using System.Workflow.Runtime;
using System.Workflow.Activities;
using System.Workflow.Runtime.Hosting;
using DocumentWorkflow;
using System.Threading;

namespace DocumentUserApplication
{
    public partial class frmMain : Form
    {
        DocumentService _service = new DocumentService();
        WorkflowRuntime _workflowRuntime;
        public frmMain()
        {
            InitializeComponent();
            this._workflowRuntime = InitWorkflowRuntime();
        }

        private WorkflowRuntime InitWorkflowRuntime()
        {
            // Get a new workflow runtime
            WorkflowRuntime wr = new WorkflowRuntime();
            wr.WorkflowCompleted += new EventHandler<WorkflowCompletedEventArgs>(wr_WorkflowCompleted);
            wr.WorkflowTerminated += new EventHandler<WorkflowTerminatedEventArgs>(wr_WorkflowTerminated);
            wr.WorkflowIdled += new EventHandler<WorkflowEventArgs>(wr_WorkflowIdled);

            // Add the external data service
            ExternalDataExchangeService dataService = new ExternalDataExchangeService();
            wr.AddService(dataService);

            // Add custom HelpDesk service
            
            dataService.AddService(this._service);
            this._service.SentToWorkflow += new EventHandler<DocumentEventArguments>(_service_SentToWorkflow);

            // Add system SQL state service
            SqlWorkflowPersistenceService stateService = new SqlWorkflowPersistenceService(
                PersistanceServiceSettings.ConnectionString);
            wr.AddService(stateService);

            // Start
            wr.StartRuntime();
            return wr;
        }

        void _service_SentToWorkflow(object sender, DocumentEventArguments e)
        {
            MessageBox.Show(string.Format("Document {0}, was successfuly sent to the workflow", e.Document), "confirmation", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            
        }

        void wr_WorkflowIdled(object sender, WorkflowEventArgs e)
        {
            MessageBox.Show(string.Format("Workflow in Idle state, with workflow instance={0}",e.WorkflowInstance.InstanceId), "confirmation", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            ThreadPool.QueueUserWorkItem(UnloadInstance, e.WorkflowInstance);
            
        }

        void wr_WorkflowTerminated(object sender, WorkflowTerminatedEventArgs e)
        {
            MessageBox.Show(string.Format("Workflow is terminated, with workflow instance={0}", e.Exception.Message), "confirmation", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            
        }

        void wr_WorkflowCompleted(object sender, WorkflowCompletedEventArgs e)
        {
            MessageBox.Show(string.Format("Workflow is completed, with workflow instance={0}", e.WorkflowInstance.InstanceId), "confirmation", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            
        }

        private void frmMain_FormClosed(object sender, FormClosedEventArgs e)
        {
            Application.Exit();
        }

        private void frmMain_Load(object sender, EventArgs e)
        {
            PopulateCategory();
        }

        private void PopulateCategory()
        {
        this.cmbCategory.DataSource=Enum.GetValues(typeof(Category));
        }

        private void btnCreateDocument_Click(object sender, EventArgs e)
        {
            if (ValidateForm())
            {
                Document _document = new Document();
                _document.Category = (Category)this.cmbCategory.SelectedItem;
                _document.Title = this.txtTitle.Text.Trim();
                _document.Description = this.txtDescription.Text.Trim();
                _document.Depositor = User.CurrentUser.UserName;
                _service.CreateDocument(_document);
                ConfirmSuccess();
            }
            else {
                MessageBox.Show("Please complete, the form's fields", "Validation, Error", MessageBoxButtons.OK
                           , MessageBoxIcon.Error);
            }
        }

        private bool ValidateForm()
        {
            if (string.IsNullOrEmpty(this.txtTitle.Text.Trim())) return false;
            if (string.IsNullOrEmpty(this.txtDescription.Text.Trim())) return false;
            return true;
        }

        private void ConfirmSuccess()
        {
            MessageBox.Show("Document, was successfuly created", "confirmation", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            ClearForm();
        }

        private void ClearForm()
        {
            this.txtDescription.Text = string.Empty;
            this.txtTitle.Text = string.Empty;
            this.cmbCategory.SelectedIndex = 0;

        }

        private void btnViewAllDocuments_Click(object sender, EventArgs e)
        {
           this.dgrdDocuments.DataSource=this._service.GetCreatedDocuments(User.CurrentUser.UserName);
        
        }

        private void btnViewOpenDocuments_Click(object sender, EventArgs e)
        {
            this.dgrdDocuments.DataSource = this._service.GetCreatedDocuments(User.CurrentUser.UserName, DocumentBaseLibrary.Status.Open);

        }

        private void btnInWorkflow_Click(object sender, EventArgs e)
        {
            this.dgrdDocuments.DataSource = this._service.GetCreatedDocuments(User.CurrentUser.UserName, DocumentBaseLibrary.Status.InWorkflow);

        }

        private void btnApproved_Click(object sender, EventArgs e)
        {
            this.dgrdDocuments.DataSource = this._service.GetCreatedDocuments(User.CurrentUser.UserName, DocumentBaseLibrary.Status.Approved);

        }
        int _documentID = default(int);
        private void submitToWorkflowToolStripMenuItem_Click(object sender, EventArgs e)
        {
              _documentID=  int.Parse(dgrdDocuments.CurrentRow.Cells["ID"].Value.ToString());
           DialogResult result=   MessageBox.Show("Are you sure that you want submit document to workflow", "confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
           Document doc = null;
            if (result == DialogResult.Yes)
           {
               doc = _service.GetDocumentByID(this._documentID);
               if (doc.Status != DocumentBaseLibrary.Status.Open)
               {
                   MessageBox.Show(string.Format("This document {0} is not in Open state", doc), "Error", MessageBoxButtons.OK
                       , MessageBoxIcon.Error);
                   return;
               }

               SubmitToWorkflow(doc);
           }
                        
        }

        private void SubmitToWorkflow(Document document)
        {
            // Fill the Parameters collection for this instance of the workflow
            Dictionary<string, object> parameters = new Dictionary<string, object>();
            parameters.Add("Depositor", User.CurrentUser);

            parameters.Add("Document", document);

            // Get the type of the workflow
            Type type = typeof(DocumentWorkflow.DocumentWorkflow);

            // Start the workflow instance
            WorkflowInstance inst = _workflowRuntime.CreateWorkflow(type, parameters);

            inst.Start();
              
        }

        private void deleteToolStripMenuItem_Click(object sender, EventArgs e)
        {
            _documentID = int.Parse(dgrdDocuments.CurrentRow.Cells["ID"].Value.ToString());
            DialogResult result = MessageBox.Show("Are you sure that you want to delete  document to workflow", "confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
            Document doc = null;
            if (result == DialogResult.Yes)
            {
                doc = _service.GetDocumentByID(this._documentID);
                if (doc.Status != DocumentBaseLibrary.Status.Open)
                {
                    MessageBox.Show(string.Format("This document {0} is not in Open state", doc), "Error", MessageBoxButtons.OK
                        , MessageBoxIcon.Error);
                    return;
                }

                this._service.DeleteDocument(doc);
            }
        }
        // Perform the unload (persist and dispose)
        static void UnloadInstance(object workflowInstance)
        {
            ((WorkflowInstance)workflowInstance).TryUnload();
        }
    }
}