Access outlook application

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Microsoft.Office.Core;
using OutlookApp = Microsoft.Office.Interop.Outlook;

namespace Shreeram
{
    class ClsSend
    {
        
        public void BillSend()
        {
            Email outlookEmail = new Email();
            outlookEmail.Message.BodyFormat = Microsoft.Office.Interop.Outlook.OlBodyFormat.olFormatPlain;
            outlookEmail.Message.Importance = Microsoft.Office.Interop.Outlook.OlImportance.olImportanceHigh;
            string dir = Application.StartupPath;
            string path = string.Format(@"{0}\{1}", dir, "Bill.pdf");
            outlookEmail.Message.Subject = string.Format("Bill: {0}", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"));
            outlookEmail.Message.Attachments.Add(path, OutlookApp.OlAttachmentType.olByValue, 1, "Bill.pdf");
            outlookEmail.Show();
        }
    }
    public class Email
    {
        /// 

        /// Gets the current instance of Outlook
        /// 

        OutlookApp.Application _outlookInstance = new Microsoft.Office.Interop.Outlook.Application();
        private OutlookApp.MailItem _message;
        public OutlookApp.MailItem Message
        {
            get
            {
                return this._message;
            }
            set
            {
                this._message = value;
            }

        }

        /// 


        /// Constructor, gets current outlook instance

        /// and creates a blank email message

        /// 


        public Email()
        {
            Initialize();
        }
        private void Initialize()
        {

            // create a blank email

            _message = (OutlookApp.MailItem)_outlookInstance.CreateItem(OutlookApp.OlItemType.olMailItem);
            // wire up the write event for logging
            _message.Write += new Microsoft.Office.Interop.Outlook.ItemEvents_10_WriteEventHandler(Message_Write);

        }
        /// 

        ///  Used for logging after the end user presses the send
        ///  button in Outlook.  If you need to log the email that was
        ///  sent to a web service or something else, fill this in.  This is
        ///  called after the email is sent via Outlook.
        /// 

        /// 

        void Message_Write(ref bool Cancel)
        {

            // ADD LOGGING HERE IF YOU NEED IT
        }
        /// 

        /// Displays the outlook screen and shows the email message.
        /// 

        public void Show()
        {
            _message.Display(false);
        }

    }
}