can i change with a lisp code the preselction colour of objects? now it is white dashed

 
Bongiorno jim78b, I think that you will find what you want in OPTIONS , SELECTION , PARAMETERS OF THE VISUAL EFFECT ( check the exact spelling on your italian release ).

i want change the color of dashed lines when you select itemstoo much to ask?

The color is inherited from the object's color. I don't thing you can change it separately.