I want to know how to create linetype with double lines one rectangle empty and other with solid in autocad(i am using autocad 2004)I tried by express tools with command mkshape (and then makelinetype command) but it is coming without solid, is it possible in autocad by using Autolisp, if yes how, can anyone help me, see attached dwg, name is linetype_ds
Since the drawing didn't get attached, I'm guessing, but.... You could do it with an embedded shape, which would need to be a closely-spaced-lines infill. Or you could do it with embedded text, using some solid square character from a font like Wingdings, perhaps several in a row. Neither of those would do curves smoothly, but you could improve on that with multiple short rectangles.
I'm afraid shapes with closely spaced lines might bee rather weighty on computer resources. Maybe you could try a different approach like associative arrays along a path. In this case you could define a block with a solid hatch to use as the array's element.
Another approach would be using a single stroke linetype on a special layer to which you could assign a 2 mm Lineweight, that is if 2mm is enough for you.