[Mono-list] System.NullReferenceException: Object reference not set to an instance of an object

[David Curylo]

Sascha,

Because of xmlns=“http://docbo…” in the outer ‘info’ node, you need to specify that namespace with SelectSingleNode.  To do so, you also need an XmlNamespaceManager.

var nsmgr = new XmlNamespaceManager(xmlDoc.NameTable);
nsmgr.AddNamespace(“whatever", "http://docbook.org/ns/docbook");
var productNumberNode = doc.SelectSingleNode(“//whatever:productnumber", nsmgr);

-Dave

> On Feb 7, 2017, at 11:15 AM, Sascha Manns <Sascha.Manns at mailbox.org> wrote:
> 
> Hello list,
> 
> i have a DocBook file with that content:
> 
> <info version="5.0" xml:id="info-Documentation-Test-Test" xmlns="http://docbook.org/ns/docbook <http://docbook.org/ns/docbook>" xmlns:xlink="http://www.w3.org/1999/xlink" <http://www.w3.org/1999/xlink%22>>
> ...
> <productnumber>0.1</productnumber>
> ...
> </info>
> 
> My goal now is to replace that number with another. I tried:
> 
> XmlDocument xmlDoc = new XmlDocument();
> xmlDoc.Load(info);
> xmlDoc.SelectSingleNode("//productnumber").InnerText = revnumber;
> xmlDoc.Save(info);
> 
> The info variable targets to the mentioned file above.
> 
> If i'm running my code i'm getting:
> 
> Exception in Gtk# callback delegate
>   Note: Applications can use GLib.ExceptionManager.UnhandledException to handle the exception.
> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object
>   at PublicanCreators.Core.RevUpd.ChangeRevision (System.String revnumber, System.String articleInfo, System.String bookInfo) [0x0003e] in /home/sascha/RiderProjects/PublicanCreators/src/PublicanCreators.Core/RevUpd.cs:85 
> 
> Maybe anyone knows how to fix that?
> 
> Greetings
> Sascha
> 
> _______________________________________________
> Mono-list maillist  -  Mono-list at lists.dot.net
> http://lists.dot.net/mailman/listinfo/mono-list

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.dot.net/pipermail/mono-list/attachments/20170207/7b8736bb/attachment.html>