更改XML文件时出错

Question

I am trying to change a XML file in code. I have found some good examples online and tried to do the same but it doesn't work. When I try my code with a simple XML document there are no errors but with my XML document I get this error :

Namespace Manager or XsltContext needed. This query has a prefix, variable, or user-defined function.

This is my XML file :

<?xml version="1.0" encoding="ISO-8859-1"?>
<ns2:VATConsignment xmlns="http://www.minfin.fgov.be/InputCommon" xmlns:ns2="http://www.minfin.fgov.be/VATConsignment" VATDeclarationsNbr="@aantal_aangiftes@">
    <ns2:VATDeclaration SequenceNumber="@aangifte_nr@">
<ns2:Declarant>
            <VATNumber>@firma_btw@</VATNumber>
            <Name>@firma_naam@</Name>
            <Street>@firma_straat@</Street>
            <PostCode>@firma_pnr@</PostCode>
            <City>@firma_wpl@</City>
            <CountryCode>BE</CountryCode>
            <EmailAddress>@firma_email@</EmailAddress>
            <Phone>@firma_tel@</Phone>
        </ns2:Declarant>
<ns2:Period>
            <ns2:Month>@maand@</ns2:Month>
            <ns2:Quarter>@kwart@</ns2:Quarter>
            <ns2:Year>@jaar@</ns2:Year>
        </ns2:Period>
<ns2:Data>
            <ns2:Amount GridNumber="0">@VAK0@</ns2:Amount>
            <ns2:Amount GridNumber="1">@VAK1@</ns2:Amount>
            <ns2:Amount GridNumber="2">@VAK2@</ns2:Amount>
            <ns2:Amount GridNumber="3">@VAK3@</ns2:Amount>

            <ns2:Amount GridNumber="44">@VAK44@</ns2:Amount>
            <ns2:Amount GridNumber="45">@VAK45@</ns2:Amount>
            <ns2:Amount GridNumber="46">@VAK46@</ns2:Amount>
            <ns2:Amount GridNumber="47">@VAK47@</ns2:Amount>
            <ns2:Amount GridNumber="48">@VAK48@</ns2:Amount>
            <ns2:Amount GridNumber="49">@VAK49@</ns2:Amount>

            <ns2:Amount GridNumber="54">@VAK54@</ns2:Amount>
            <ns2:Amount GridNumber="55">@VAK55@</ns2:Amount>
            <ns2:Amount GridNumber="56">@VAK56@</ns2:Amount>
            <ns2:Amount GridNumber="57">@VAK57@</ns2:Amount>
            <ns2:Amount GridNumber="59">@VAK59@</ns2:Amount>

            <ns2:Amount GridNumber="61">@VAK61@</ns2:Amount>
            <ns2:Amount GridNumber="62">@VAK62@</ns2:Amount>
            <ns2:Amount GridNumber="63">@VAK63@</ns2:Amount>
            <ns2:Amount GridNumber="64">@VAK64@</ns2:Amount>
            <ns2:Amount GridNumber="65">@VAK65@</ns2:Amount>
            <ns2:Amount GridNumber="66">@VAK66@</ns2:Amount>

            <ns2:Amount GridNumber="71">@VAK71@</ns2:Amount>
            <ns2:Amount GridNumber="72">@VAK72@</ns2:Amount>

            <ns2:Amount GridNumber="81">@VAK81@</ns2:Amount>
            <ns2:Amount GridNumber="82">@VAK82@</ns2:Amount>
            <ns2:Amount GridNumber="83">@VAK83@</ns2:Amount>
            <ns2:Amount GridNumber="84">@VAK84@</ns2:Amount>
            <ns2:Amount GridNumber="85">@VAK85@</ns2:Amount>
            <ns2:Amount GridNumber="86">@VAK86@</ns2:Amount>
            <ns2:Amount GridNumber="87">@VAK87@</ns2:Amount>
            <ns2:Amount GridNumber="88">@VAK88@</ns2:Amount>
            <ns2:Amount GridNumber="91">@VAK91@</ns2:Amount>
        </ns2:Data>
<ns2:ClientListingNihil>@nihil_listing@</ns2:ClientListingNihil>
        <ns2:Ask Payment="NO" Restitution="NO"/>
        <ns2:Comment>@commentaar@</ns2:Comment>
    </ns2:VATDeclaration>
</ns2:VATConsignment>    

And this is my code i have written :

        XmlDocument doc2 = new XmlDocument();
        doc2.Load(@"C:\Users\Kevin\Desktop\xsd\TemplateAangifte.xml");

        XmlNode aangeverNode = doc2.SelectSingleNode(@"/ns2:VATConsignment/ns2:VATDeclaration/ns2:Declarant");

The error gets triggered when trying to load the XmlNode . I am pretty new to the XML story so every help is welcome !

Thanks !

Kevin

Answer 1

You need to set up the namespace manager mapping each namespace that is declared in your XML source file and that you use in your XPath expression with a prefix. The prefix that you declare in the mapping should be used in your XPath selectors. The prefix need not be the same as the one used in the source file (it may be the same as the original prefix, but it doesn't have to be).

Here are the declarations you need to add if you want to access any element from your source file:

XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc2.NameTable);
nsmgr.AddNamespace("ns2", "http://www.minfin.fgov.be/VATConsignment");

// Not necessary unless you decide to use an unprefixed element from your source
nsmgr.AddNamespace("ns0", "http://www.minfin.fgov.be/InputCommon"); 

To access an unprefixed element, you would use ns0:EmailAddress for example.