ThreadStatic Modified with Static C#

I have some code where I use a thread static object in C#.

[ThreadStatic]
private DataContext connection 

I was wondering, in this case, what if any change would I get if I put the static modifier on the thread static context?

[ThreadStatic]
private static DataContext connection 

With the first would there be one copy of the context per instance per thread, with the other only one copy per thread?

Solution 1:

The ThreadStaticAttribute is only designed to be used on static variables, as the documentation points out. If you use it on an instance variable, I suspect it will do precisely nothing.

Solution 2:

In the first case it would probably be ignored, whereas in the second case you are correct, one instance per thread.

Solution 3:

In Microsoft Docs, it says:

Indicates that the value of a static field is unique for each thread.

So I guess your first case is incorrect. The attribute will probably be ignored.