Professional ASP.NET 1.1 [Electronic resources] نسخه متنی

Data Types

ASP.NET Web services support all the primitive types supported in the CLR. In addition to the simple primitive types, arrays of primitives are also supported. More interesting, however, is the support for user-defined classes and structs. Essentially, anything that can be represented by an XSD schema can be a parameter or return type of an ASP.NET Web service.

Custom Types

Suppose you want to build an ASP.NET Web service that returns a user-defined class named CustomerRecord. This returns some string and integer values, as well as an array of another, user-defined, class named Order:

Public Class CustomerRecord
Public Customer As String
Public Address1 As String
Public Address2 As String
Public Phone As String
Public Email As String
Public CustomerOrder(2) As Order
End Class
 
Public Class Order
Public OrderNumber As Integer
Public Name As String
Public Cost As String
Public ShipDate As String
End Class

You could write the following WebMethod that returned an instance of CustomerRecord:

Public Class OrderDetails
<WebMethod()> Public Function RequestOrderDetails() As CustomerRecord
Dim customerRecord As New CustomerRecord
' Set data...
customerRecord.Customer = "JohnDoe"
customerRecord.Address1 = "22913 Crestpark Dr"
customerRecord.Address2 = "Houston, Tx 79043"
customerRecord.Phone = "281-475-0938"
customerRecord.Email = "john@customer.com"
customerRecord.CustomerOrder(0) = New Order()
customerRecord.CustomerOrder(0).OrderNumber = 12
customerRecord.CustomerOrder(0).Name = "Product A"
customerRecord.CustomerOrder(0).Cost = "$23.45"
customerRecord.CustomerOrder(0).ShipDate = "8/6/01"
 
customerRecord.CustomerOrder(1) = New Order()
customerRecord.CustomerOrder(1).OrderNumber = 15
customerRecord.CustomerOrder(1).Name = "Product C"
customerRecord.CustomerOrder(1).Cost = "$13.41"
customerRecord.CustomerOrder(1).ShipDate = "7/1/01"
 
Return customerRecord
End Function
End Class

As long as the user-defined class represents its data using primitive types, and those types are public, the data will be sent correctly to the caller. If, however, the class used Get/Set properties and modified private variables within the class, the data would not be sent correctly – XML is not used to describe the binary representation of the object in memory. Now that you're more familiar with the data types and the general ASP.NET Web service .asmx file, let's take a deeper look at two of the attributes used most often when building ASP.NET Web services.