SoapHeader Class
Assembly: System.Web.Services (in system.web.services.dll)
SOAP headers offer a method for passing data to and from an XML Web service method if the data is not directly related to the XML Web service method's primary functionality. For instance, an XML Web service might contain several XML Web service methods that each require a custom authentication scheme. Instead of adding parameters to each XML Web service method for the custom authentication scheme, a SoapHeaderAttribute, referring to a class deriving from SoapHeader, can be applied to each XML Web service method. The implementation for the class deriving from SoapHeader handles the custom authentication scheme. In this manner, the XML Web service method implements only the functionality specific to it and adds additional functionality using a SOAP header.
The following list outlines the basic steps to receiving and processing a SOAP header:
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Create a class that derives from SoapHeader representing the data passed into the SOAP header.
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Add a member to the class implementing an XML Web service or an XML Web service client proxy class, of the type created in the first step.
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Apply a SoapHeaderAttribute to the XML Web service method or the corresponding method in the proxy class, specifying the member created in the second step in the MemberName property.
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Within the XML Web service method or XML Web service client code, access the MemberName property to process the data sent in the SOAP header.
The following MyWebService XML Web service defines the MyHeader SOAP header and requires it to be sent with any calls to the MyWebMethod XML Web service method. Additionally, MyWebMethod receives any SOAP headers other than the MyHeader SOAP header.
<%@ WebService Language="VB" Class="MyWebService"%> Imports System.Web.Services Imports System.Web.Services.Protocols Imports System.Xml Imports System ' Define a SOAP header by deriving from the SoapHeader base class. Public Class MyHeader Inherits SoapHeader Public MyValue As String End Class Public Class MyWebService Public theHeader As MyHeader ' Receive all SOAP headers besides the MyHeader SOAP header. Public unknownHeaders() As SoapUnknownHeader 'Receive any SOAP headers other than MyHeader. <WebMethod, _ SoapHeader("theHeader", Direction := SoapHeaderDirection.InOut), _ SoapHeader("unknownHeaders")> _ Public Function MyWebMethod() As String Dim header As SoapUnknownHeader For Each header In unknownHeaders ' Perform some processing on the header. If header.Element.Name = "MyKnownHeader" Then header.DidUnderstand = True Else ' For those headers that cannot be ' processed, set the DidUnderstand propert to false. header.DidUnderstand = False End If Next header Return "Hello" End Function End Class
System.Web.Services.Protocols.SoapHeader
System.Web.Services.Protocols.SoapUnknownHeader
Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.