How to find out that MailItem object is a new Email or an recieved mail

I am creating an Outlook 2010 Addin,
Now I am giving the feature to open a new email window or an received email.

but I need to figure out that MailItem object is a new email or an Received email object.
could any help me out here

I am this code
 Dim MailItem As Outlook._MailItem
        Dim Application As Outlook.Application
       
        Application = New Outlook.Application()
        For Each inspector In Application.Inspectors
            If TypeOf inspector.CurrentItem Is Outlook.MailItem Then
                MailItem = inspector.CurrentItem
                MailItem.Body += PropertyInfoString
                Exit Sub
            End If
        Next inspector

        MailItem = TryCast(Application.CreateItem(Outlook.OlItemType.olMailItem), Outlook._MailItem)
        If MailItem IsNot Nothing Then
            MailItem.Body += PropertyInfoString
            MailItem.Display(False)
        End If