Outlook 2007 vsto add-in. Get email sender address

Here I am presenting a method that can be used to get sender's email address by passing an email item as a reference. The method it self will decide weather the sender's email address type is SMTP or Exchange. If it is Exchange, it will convert the email address into SMTP. Here is the code.

    internal static string GetSenderEmailAddress(ref Outlook.MailItem oM)
    {
        Outlook.PropertyAccessor oPA = null;
        Outlook.AddressEntry oSender = null;
        Outlook.ExchangeUser oExUser = null;

        string SenderID;
        string senderEmailAddress;

        try
        {                
            if (oM.SenderEmailAddress.Contains("@") && oM.SenderEmailAddress.Contains(".com")) //Handing smtp email addresses
            {
                senderEmailAddress = oM.SenderEmailAddress;
            }
            else //Handing exchange email addresses
            {
                // Create an instance of PropertyAccessor 
                oPA = oM.PropertyAccessor;
                // Obtain PidTagSenderEntryId and convert to string 
                SenderID = oPA.BinaryToString(oPA.GetProperty("http://schemas.microsoft.com/mapi/proptag/0x0C190102"));
                // Obtain AddressEntry Object of the sender 
                oSender = Globals.ObjNS.GetAddressEntryFromID(SenderID);

                oExUser = oSender.GetExchangeUser();
                senderEmailAddress = oExUser.PrimarySmtpAddress;
            }
            Debug.DebugMessage(3, "OutlookHelper : GetSenderEmailAddress() : Completed");
            return senderEmailAddress;
        }
        catch (Exception ex)
        {
            MessageBox.Show( ex.Message);
            return null;
        }
        finally
        {
            if (oExUser != null) Marshal.ReleaseComObject(oExUser);
            if (oSender != null) Marshal.ReleaseComObject(oSender);
            if (oPA != null) Marshal.ReleaseComObject(oPA);
        }
    }

In Outlook 2007 you can do it like this:

private string GetSmtpAddress(Outlook.MailItem oItem)
{
    Outlook.Recipient recip;
    Outlook.ExchangeUser exUser;
    string sAddress;

    if (oItem.SenderEmailType.ToLower() == "ex")
    {
        recip = Globals.ThisAddIn.Application.GetNamespace("MAPI").CreateRecipient(oItem.SenderEmailAddress);
        exUser = recip.AddressEntry.GetExchangeUser();
        sAddress = exUser.PrimarySmtpAddress;
    }
    else
    {
        sAddress = oItem.SenderEmailAddress.Replace("'", "");
    }
    return sAddress;
}