Re: [dotNetRDF-Support] NullReferenceException in Graph g = new Graph();

[Rob V. <ra...@ec...>]

Hi Ross

Yes this is a known issue but it is also a non-issue, see CORE-292 [1]

Basically an external library we use does a check to see if the hash
function provided supports null keys and catches the
NullReferenceException and swallows it.  For some reason in the 0.8.x
releases VS would report this as unhandled even when it was actually
handled.  The fix we made in 0.9.0 for this was to include the PDBs in the
NuGet packages which results in VS correctly ignoring the error most of
the time.

However you can still see this error if you have Break on Thrown set for
CLR exceptions.

The error is completely harmless and if you keep clicking Continue in the
debugger the code will proceed to run fine, unfortunately each Graph
instance has 4-7 instances of the culprit data structure under the hood so
you will have to click a whole bunch of times.

There will be a more comprehensive fix for this coming care of an updated
version of the external library which we will use for 1.0.0 which should
eliminate even the thrown exception.

Hope this helps,

Rob

p.s. I was awarded my PhD officially in December, thanks for the good
wishes :)

[1]: http://dotnetrdf.org/tracker/Issues/IssueDetail.aspx?id=292

On 2/22/13 7:12 AM, "Ross Horne" <ros...@gm...> wrote:

>Hi Rob,
>
>We're having difficulty with the dotNetRDF libraries. The latest 4.0
>library works well on mono. However, when we try through Visual Studio
>10.0 for .NET 4.0, when trying to create a new graph, as follows,
>
>Graph g = new Graph();
>
>we get the following error:
>
>"NullReferenceException was unhandled by user code."
>
>Is this a known problem with a particular combination of version?
>Thank you for any pointers.
>
>Also, good luck with your viva, I notice you have submitted!
>
>Regards,
>
>Ross