Earlier today I was creating a new class file for a project of mine in Visual Studio.
Then I went on using the class defined in that file in a web form, but, to my surprise, the class was inaccessible.
I double checked the access level of the class, but it appears that wasn’t the issue, so I started googling for this problem, but I ended up looking at situation different from mine and not really useful.
After a few minutes of scratching my head on this unusual problem, I finally had a look at a pane I rarely look at:
In the Properties pane, the Build Action was set to Content instead of Compile: this is the ways of telling the IDE to include this file in the project as a static resource. So, in this case, the class file was included as a simple plain text file with no action performed on it: no compilation mean of course no usable class, so that was the reason for the seemingly inexplicable behavior.