How to pass data between one Window to one view in WPF?

Hi all of you,

When I run my app the first thing is launching my Window Logon where the user can do logon against my rdbms, fine till here. I would need to pass data to my main view from this window but I do not how, 'cause I am trying to assign one value to one public class member but it does not appear in the list of methods and properties:

	MasterGIT.????????	instead of MasterGIT.mUserConnected = User

Code-behind Logon Window:

 Private Sub Endavant_Click(sender As Object, e As RoutedEventArgs)

       Try

            Exit Sub

           If Not existeLogin() Then

                WpfMessageBox.Show("El Usuario o la contraseña introducida es incorrecta", "GIT", WpfMessageBoxButton.OK, WpfMessageBoxImage.Error)


                limpia()
     

           End If
   
       Catch ex As Exception

        End Try

	MasterGIT.????????	
        Me.DialogResult = True
        
	
    End Sub

Code behind for MasterGIT (View):

 Public _mUserConnected As String

    Public Property mUserConnected() As String
        Get
            Return _mUserConnected
        End Get
        Set(ByVal value As String)
            _mUserConnected = value
        End Set
    End Property
  Public Sub New()

        Me.InitializeComponent()

        CultureManager.UICulture = Thread.CurrentThread.CurrentCulture
        mVentana3 = New Logon_GIT()

        If mVentana3.ShowDialog() = True Then

        Else

        End If

    End Sub

Thanks for any hint,

Primary platform is Windows 7 Ultimate 64 bit along with VS 2012/Sql2k8 for WPF and SilverLight stuff