Has anyone ever tried using pinhole eyeglasses to prevent their eyesight from worsening?

Unsuccessfully: That is a great idea that has some logic to it. Unfortunately though, the refractive error of the eyes does not change on the basis of whether there are straight or divergent light rays coming into it (the pinholes eliminate the divergent light rays and only allow the straight ones in). Plus, while you can see targets clearer with the pinholes, it effectively obliterates your visual field.

Yes, in the past: In fact, pinhole eyeglasses were often used a few hundred years ago. The problem with the pinhole is that it makes things appear dimmer, reduces peripheral vision, and just as with all glasses, cannot prevent or stop vision changes. A person would have better focus only while wearing the glasses, but the above side effects make pinhole glasses impractical.