1). Best way to add the reference using solution file not directly add reference the dll of DAL to BLL AND BLL TO UI.
follow the below steps and complete the reference using solution file.
1). Step 1- Right click on BLL and go to add reference.
2). Reference Manager window will display.
Select Projects – all dependent solutions files will display.
Select the solutions file,and build your project.
It will never give the error either you clean the project or rebuild again.
You can see below picture also for reference.
Step 2 :