先实现WebServiceBase, 然后，创建Web Service
Imports System.Web.Services
<WebService(Namespace:="http://tempuri2.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
Public Class WSTest
Inherits WebServiceBase
<WebMethod()> _
Public Function HelloWorld() As String
Return "Hello World"
End Function
End Class