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SoapHeader.DidUnderstand Property

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Definition

Namespace:
System.Web.Services.Protocols
Assembly:
System.Web.Services.dll

Gets or sets a value indicating whether an XML Web service method properly processed a SOAP header.

public:
 property bool DidUnderstand { bool get(); void set(bool value); };
public bool DidUnderstand { get; set; }
member this.DidUnderstand : bool with get, set
Public Property DidUnderstand As Boolean

Property Value

Boolean

true if the SOAP header was properly processed; otherwise false.

Examples

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, the MyWebMethod receives any SOAP headers other than the MyHeader SOAP header. For SOAP headers that MyWebMethod can process, DidUnderstand is set to true.

<%@ WebService Language="C#" Class="MyWebService"%>
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml;
using System;

// Define a SOAP header by deriving from the SoapHeader base class.

public class MyHeader : SoapHeader {
    public string MyValue;
}

public class MyWebService {

    public MyHeader myHeader;
    // Receive all SOAP headers besides the MyHeader SOAP header.
    public SoapUnknownHeader[] unknownHeaders;
 
    [WebMethod]
    [SoapHeader("myHeader", Direction=SoapHeaderDirection.InOut)]

    //Receive any SOAP headers other than MyHeader.
    [SoapHeader("unknownHeaders",Required=false)]

    public string MyWebMethod() {

       foreach (SoapUnknownHeader header in unknownHeaders) {
           // Perform some processing on the header.
       if (header.Element.Name == "MyKnownHeader")
               header.DidUnderstand = true;
       else
                // For those headers that cannot be  
                // processed, set the DidUnderstand property to false.
                header.DidUnderstand = false;
       }
       return "Hello";
    }
}

<%@ 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

Remarks

For SOAP headers defined by an XML Web service, ASP.NET assumes the XML Web service method properly processed the SOAP header by setting the initial value of DidUnderstand to true. For SOAP headers not defined by the XML Web service, the initial value is false. If ASP.NET detects SOAP headers passed to an XML Web service method with DidUnderstand set to false after the method returns, a SoapHeaderException is thrown back to the XML Web service client instead of the results from the XML Web service method.

Applies to

See also