Each web service begins as a stateless class with one or more methods that the remote clients call to invoke your code.
BookService is designed to allow remote clients to retrieve information about books provided by the store. The class provides GetBooks() method that returns a DataSet with the full set of books information. It also provides a GetBooksCount() method, which simply return the number of books in the database. In this case you need some basic ADO.NET code to provide these methods.
Public Class BooksService
Private connectionString As String
Public Sub New()
Dim connectionString As String = WebConfigurationManager.ConnectionStrings(“BookStore”).ConnectionString
End Sub
Public Function GetBooksCount() As Integer
Dim con As New SqlConnection(connectionString)
Dim sql As String = “SELECT COUNT(*) FROM Books”
Dim cmd As New SqlCommand(sql, con)
‘ Open the connection and get the value.
con.Open()
Dim numBooks As Integer = -1
Try
numBooks = CInt(cmd.ExecuteScalar())
Finally
con.Close()
End Try
Return numBooks
End Function
Public Function GetBooks() As DataSet
‘ Create the command and the connection.
Dim sql As String = “SELECT ISBN, AuthorLName, AuthorFName, Title, ” & “Pages, Price FROM Books”
Dim con As New SqlConnection(connectionString)
Dim da As New SqlDataAdapter(sql, con)
Dim ds As New DataSet()
‘ Fill the DataSet.
da.Fill(ds, “Books”)
Return ds
End Function
End Class
You can use GetBooks() and GetBooksCount() in any web page in the same project, because both methods are public.