I am maintaining an application in Delphi XE that has used a small, non-visual plugin I wrote in Visual Studio 2015 with Oxygene. It’s been working with Hydra 4 quite well.
I recently upgraded to Hydra 5 (5.0.85.1141), recompiled both the Delphi app and the .NET plugin and now I get an error when it tries to load the plugin.
When I originally wrote the .NET plugin, I also wrote two other plugins, one in Delphi, and another one in .NET that were very simple, just test plugins to show a message. I used these to learn how to use Hydra and prove that the plugin system was working as I tested in various environments.
Testing with these two very simple plugins, I found the Delphi plugin works fine, but the .NET one does not. Once again, these are the simplest, non-visual plugins that could be written.
The error I get when I call HYModuleManager.CreateNonVisualPlugin breaks in THYManagedPluginFactory.CreateInstance with the error “Interface not supported” quickly followed by “Unknown update list {…GUID…}.”
I did not see an “update notes” document. Is there something I’m supposed to do different when using Hydra 5? An interface change or class attribute I missed?
Hmm… I had run the “Check for new versions” from the Everwood Welcome screen and it didn’t show a new version of Hydra–I had only downloaded it a few weeks ago, so didn’t think to check myself. But yes, there is a newer build.
Alas, after installing the latest build and recompiling all the libraries and double-checking all files are up to date, and rebuilding both the Delphi app, plugin, and VS plugins, I’m getting the same problem.
There is one slight difference: it breaks just a few lines earlier in THYManagedPluginFactory.CreateInstance when it’s calling CreateManagedPluginInstance with the error message: “Exception has been thrown by the target of an invocation.” (Previously, it was breaking on the last line of the CreateInstance method.)
The issue you have if caused by the missing licenses.licx file.
Despite it is mentioned in the .oxygene project file, the licenses.licx file itself is missing from the Properties folder. This makes it not possible to instantiate the plugin while loading.
Well, this explains why it worked earlier and started to fail now.
licenses.licx has version # explicitly specified. When the plugin is being build, .NET licensing system checks your license and complies .licx file into a resource. Issue is that this compiled resource contains licenses for Hydra assemblies others that are used by the plugin. So it fails with licensing error as expected.
You neeed to change the licensing.licx file to this single line:
Then delete the obj folder in your project’s folder (VS doesn’t always do this even on build cleanup) and rebuild the plugin. Everything will work as it should after that.
But it leaves a couple of questions… Why was the version information in there in the first place? I never manually edited the license file before. Do I have to check the license file for other .NET projects?
Visual Studio does that for you (it is not our code, it is just how VS works). When it detects that one just have added a component that requres .NET licensing stuff (either dragged some component from the Toolbox or added something via the ‘Add New Item’ menu, like Non-Visual Hydra plugin) VS does the folllowing:
It scans the current project for licenses.licx file
If there is no such file it is added
Contents of the file is scanned for a line that satisfies the license definition of the entity just added (* see below)
If such line is not found then the license definition is added to the .licx file containing full assembly information including version #
Note: By ‘satisfies’ here I mean that f.e. if you just have added a Non-Visual Plugin and referenced Hydra build 5.0.87.1149 then VS will check for lines
(ie license definitions with ful correct version info or w/o any version info at all).
It is better to. Actually you can just run a search on all licenses.licx files containing word “PublicKeyToken”. This search will show all license files with excessive version information.
