Text box is not populating with parameter values

Hi, 

I have two parameters called "Company Id" & 'Terminal Id". User will select the id's from these two parameters and the selected id's need to be shown as a list separated by commas in a text box. 

I have added the below formulas in the text boxes.

Company ID =JOIN(Parameters!VUFSDAILYPROFITRPTCOMPANYID.Value," , ")

Terminal ID =JOIN(Parameters!VUFSDAILYPROFITRPTORIGTERMINALID.Value," , ")

However, it is showing the values like this below in the text boxes (table name, schema name) instead of the ID when the report runs.

Any help on this would be greatly appreciated.

Thanks in advance !