sending outlook email

[miry2j]

I am trying to write a dll to send email with a hook to outlook.
The problem I am having is with the attachments. In my test app if I put in the To, Subject and the attachment. It will send me the email. If I leave out the attachment in the test app I get an exception null reference. Not sure how to go about sending the email whether it has the attachment or not.
Any help would be appreciated. Here is my code for my email class:

Imports Outlook
 
Public Class Email
    Private mOutLookApp As Outlook.Application
    Private mNameSpace As Outlook.NameSpace
    Private mItem As Outlook.MailItem
    Private strAttach As String
 
    Public Event emailUpdate(ByVal status As String, ByVal code As Integer)
    Public Event emailSubject(ByVal status As String, ByVal cod As Integer)
 
    'mNameSpace.Logon(, , False, True)
 
    Private mMailSubject As String
    Private mMailTo As String
    Private mMailAttachment As String
 
 
 
    Public Sub New()
 
        mOutLookApp = New Outlook.Application
        mNameSpace = mOutLookApp.GetNamespace("MAPI")
        
    End Sub
 
 
 
    Public Property MailSubject() As String
        Get
            Return mMailSubject
        End Get
        Set(ByVal MailSubject As String)
            
            mMailSubject = MailSubject
        End Set
    End Property
    Public Property MailTo() As String
        Get
            Return MailTo
        End Get
        Set(ByVal MailTo As String)
           
            mMailTo = MailTo
        End Set
    End Property
    Public Property MailAttachment() As String
        Get
            Return MailAttachment
        End Get
        Set(ByVal MailAttachment As String)
            
            mMailAttachment = MailAttachment
        End Set
    End Property
 
    Public Function SendAttachment() As Boolean
        If mMailAttachment <> "" Then
            'send attachment
            Return True
        End If
    End Function
 
 
 
    Public Function SendMail() As Integer
        Try
            If mMailTo = "" Then
                RaiseEvent emailUpdate("mail to address is blank", -125)
                Return -1
            Else
            End If
            If mMailSubject = "" Then
                RaiseEvent emailSubject("mail subject is blank", -135)
                Return -1
            Else
            End If
            If mMailAttachment = "" Then
                mItem.Send()
            End If
 
 
            Dim t As New System.Threading.Thread(AddressOf SendMailThread)
            t.Start()
            Return 1
        Catch ex As System.Runtime.InteropServices.COMException
            Return -1
 
        End Try
 
 
    End Function
 
    Private Sub SendMailThread()
 
        Try
            mItem = mOutLookApp.CreateItem(0)
            mItem.To = mMailTo
            mItem.Subject = mMailSubject
            If mItem.Attachments.Add(mMailAttachment) Is Nothing Then
                mItem.Send()
                System.Windows.Forms.MessageBox.Show("success, email  sent")
            Else
 
                mItem.Attachments.Add(mMailAttachment)
                mItem.Send()
                System.Windows.Forms.MessageBox.Show("success, email and attachment sent")
            End If
 
        Catch ex As System.Runtime.InteropServices.COMException
            MsgBox("error mail not sent")
 
        End Try
 
    End Sub
 
End Class

Here is the code in my test app. All my test app is a form with a button.

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        gobjemail.MailTo = txtTo.Text
        gobjemail.MailSubject = txtSubject.Text
        gobjemail.MailAttachment = txtAttachment.Text
        gobjemail.SendMail()
        
    End Sub
 
    Private Sub gobjemail_emailUpdate(ByVal status As String, ByVal code As Integer) Handles gobjemail.emailUpdate
        MsgBox("email update")
    End Sub
 
    Private Sub gobjemail_emailSubject(ByVal status As String, ByVal code As Integer) Handles gobjemail.emailUpdate
        MsgBox("email subject")
    End Sub
 
End Class