the SOLIDWORKS Professional and Premium include ScanTo3D. When you turn on ScanTo3D you will get additional file import file types in the open dialog and with it you can import STL files as meshes:
After you have imported the file you can turn on Shaded with Edges, Wireframe or Hidden Lines Visible and you should see the mesh triangles.
Product Definition Team
Thank you Frank,
this is exactly i was searching for!