At present, parameters are static lists of selectable information that require manual intervention to update them.
Can I suggest that you up-vote for this: Dynamic parameters
Also, Johnathan Drummey created a workaround using a data-blend for this a while ago: Creating a Dynamic “Parameter” with a Tableau Data Blend | Drawing with Numbers
Currently this feature is not available but you can have a look.
You can try this .Update the parameter manually by using the following procedure:
- Right-click the parameter name in the Parameters pane and then select Edit.
- In the Edit Parameter dialog box that opens, click Set from Field.
- From the drop-down list, select the field for which you want to update the values, and then click OK.
The ability for parameter values to update automatically when the underlying data changes is not currently built into the product.