DUVIDA WCF

<ServiceContract()> _
Public Interface IService

    <OperationContract()> _
    Function ValidarEmail(ByVal email As String) As Boolean

End Interface

Public Class Service
    Implements IService

    Public Sub New()
    End Sub

    Public Function ValidarEmail(ByVal email As String) As Boolean Implements IService.ValidarEmail
        Dim validaEmail As String = [Ô]^[A-Za-z0-9](([_\.\-]?[a-zA-Z0-9]+)*)@([A-Za-z0-9]+)(([\.\-]?[a-zA-Z0-9]+)*)\.([A-Za-z]{2,})$[Ô]

        Return Regex.IsMatch(email, validaEmail)
    End Function

End Class

        [ô]criando uma instância do nosso serviço WCF
        Dim WCF_ValidaEmail As New ServiceReference.Service1Client

        [ô]usando o método ValidarEmail do nosso serviço
        If WCF_ValidaEmail.ValidarEmail(txtEmail.Text) Then
            MsgBox([Ô] Email Válido.[Ô])
        Else
            MsgBox([Ô] Email Inválido.[Ô])
        End If