回复：谢谢楼上两位的答复，请问.....

Yes. Going to Canada means you will abandon your current pending I-485. But you can apply for immigrant visa through consolate process when your PD, which is receipt date of your I-140, becomes current since you have a approved I-140. But I doubt you will come back at that time and start everything from begining if you have a steady job in Canada.