Labs · Power BI

Lab: Turn the File Path into a Power Query Parameter So the Report Works on Any Laptop

By Ravindra Bagale · Last updated: 8 October 2026

Suppose we are…

Suppose we are on the MIS team at Bajaj Finserv in Pune. Asha built a sales report on her laptop. The Source step says C:\Users\Asha\Downloads\pbi_sales.csv. She goes on leave and Rahul opens the report on his laptop. His Windows user is "Rahul" and he keeps files in a different folder, so Refresh fails. Rahul would have to open Power Query and edit every query by hand.

A parameter is a named value (like a small variable) that queries can use. If the folder lives in one parameter, Rahul changes one box and everything works. The sales data is sample data made up for practice.

Goal of this lab

By the end you will have:

• A text parameter FolderPath.
• A Source step that reads FolderPath & "pbi_sales.csv" instead of a fixed path.
• Broken the refresh on purpose by moving the file, then fixed it with Edit parameters in seconds.
• A template file (.pbit) that asks for the folder when someone opens it.

What you need (all free)

• Power BI Desktop.
• The file: Download pbi_sales.csv (24 orders)
• 30 minutes.

The data: before and after

Before. The path is typed inside the Source step. On another laptop the file is not found.

After. The folder lives in a parameter. Rahul changes only the parameter value.

The formula

This is the only line of code we change. Before:

= Csv.Document(File.Contents("C:\PowerBI\Labs\pbi_sales.csv"), [Delimiter=",", Columns=7, Encoding=65001, QuoteStyle=QuoteStyle.None])

After:

= Csv.Document(File.Contents(FolderPath & "pbi_sales.csv"), [Delimiter=",", Columns=7, Encoding=65001, QuoteStyle=QuoteStyle.None])

& joins two pieces of text in M. If FolderPath is C:\PowerBI\Labs\, then FolderPath & "pbi_sales.csv" becomes C:\PowerBI\Labs\pbi_sales.csv, exactly the old path. That is why the parameter value must end with a backslash.

Steps

1. Create the folder C:\PowerBI\Labs and save pbi_sales.csv in it.
2. In Power BI Desktop: Get data → Text/CSV, pick C:\PowerBI\Labs\pbi_sales.csv, click Transform Data.

3. In Applied Steps, click Source. If you do not see the formula bar above the table, tick View → Formula Bar.

   👁 What you should see: the formula bar shows = Csv.Document(File.Contents("C:\PowerBI\Labs\pbi_sales.csv"), ….

4. Click Home → Manage Parameters → New Parameter. Fill in: Name FolderPath, Type Text, Suggested Values Any value, Current Value C:\PowerBI\Labs\ (with the backslash at the end). Click OK.

   👁 What you should see: FolderPath in the Queries list on the left, with a small parameter icon and the value C:\PowerBI\Labs.

5. Click the pbi_sales query, then its Source step. In the formula bar, select the text "C:\PowerBI\Labs\pbi_sales.csv" (including the quotes) and replace it with FolderPath & "pbi_sales.csv". Press Enter.

   👁 What you should see: the same 24 rows; no error. Click the last step in Applied Steps to check the final table is fine too.

6. Click Home → Close & Apply. Add a Card with Sales.

   👁 What you should see: 1.30M. Save the file as Lab-10-parameter.

7. Now play Rahul. Create the folder C:\Users\Public\Documents\SalesData and move (cut and paste) pbi_sales.csv from C:\PowerBI\Labs into it. In Power BI click Home → Refresh.

   👁 What you should see: an error like Could not find file 'C:\PowerBI\Labs\pbi_sales.csv'. Close the message.

8. Click the small arrow under Home → Transform data and choose Edit parameters. Change FolderPath to C:\Users\Public\Documents\SalesData\ and click OK, then Apply changes.

   👁 What you should see: the refresh runs and the card shows 1.30M again. You did not open Power Query.

9. Click File → Export → Power BI template, type a description such as "Sales report. Set FolderPath to the folder with pbi_sales.csv" and save as Lab-10-sales.pbit.

10. Close Power BI and double-click Lab-10-sales.pbit.

    👁 What you should see: a window asking for FolderPath before anything loads. Enter C:\Users\Public\Documents\SalesData\ and click Load. This is exactly what Rahul would do.

Common mistakes

Self-check checklist

Try-at-home challenge

Your manager wants the same report for two branches whose files have different names: pbi_sales.csv and pune_sales.csv. Make the file name a second parameter, FileName, so both the folder and the file can change.

= Csv.Document(File.Contents(FolderPath & FileName), [Delimiter=",", Columns=7, Encoding=65001, QuoteStyle=QuoteStyle.None])

Samjla ka? Put the folder in a parameter, join it with &, and end it with a backslash. Aata pudhe jaauya: build a proper star schema with a Date, Product and City table.