I am not sure I understand your question correctly. Are you looking to have a drop down with various measures listed on it? I presume that you are looking to provide the user an option to select which measure they would like to view on the viz. Is that correct?
If that is the case, you should be able to achieve this by creating a parameter with the measures listed and creating a calculated field that selects the measure to be displayed based on the parameter selected. I have attached a workbook for your reference. Is this what you were looking for?
Measure Filter.twbx.zip 396.8 KB
I tried this method, what if i want to include calculated fields? it says i cannot mix aggregate and non aggregate comparisons or results in case expressions...
To turn a non-aggregate field into an aggregate to use for comparison, you can use any aggregation in Tableau. Common ones are MIN() and ATTR(). ATTR() is a special Tableau function that returns the value if there is only one value possible to be returned, otherwise it returns * which means many values.