I was able to successfully import it as a surface plane. (thus, 2D)
Here was my method:
Drag+Drop test.dxf into SolidWorks Window
In the first menu, select "Import to a new part as" "3D curves or model"
And it worked properly for me. (I think)
I have attached my .sldprt
test_cc_1.SLDPRT.zip 52.1 KB
Yes, your suggestion worked.
Wow....that was so easy, I didn't even think to do that.