Labs · Power BI

Lab: Switch the Chart's Measure with a Field Parameter and Add a Top N Selector

By Ravindra Bagale · Last updated: 8 October 2026

Suppose we are…

Suppose the Croma sales director, the finance head and the logistics head all use the same page. The director asks for Sales by city, finance for Profit, logistics for Units. And all three say "show me only the top 2" one day and "top 3" the next. Instead of six charts, we build one chart with a Metric slicer and one chart with a Top N slider. The numbers are sample data made up for practice.

Goal of this lab

By the end you will have:

• A field parameter called Metric with Total Sales, Total Profit and Units, and a slicer to choose one.
• A numeric range parameter called Top N (1 to 4) with a slider.
• A chart that shows only the top N cities by sales, using RANKX.

What you need (all free)

• Power BI Desktop and a star-schema file from Lab 11 or later.
• Sample data if you need to rebuild: Download pbi_sales.csv (24 orders) Download pbi_cities.csv Download pbi_products.csv
• 40 minutes.

The data: before and after

Before. One chart, one fixed measure.

After. The Metric slicer chooses which column the chart shows; Top N = 2 keeps only the two best cities by sales.

The formula

Two base measures (skip any you already have):

Total Profit = SUM ( pbi_sales[Sales] ) - SUM ( pbi_sales[Cost] )
Units = SUM ( pbi_sales[Units] )

When you create the field parameter, Power BI writes this table for you:

Metric = {
    ( "Total Sales", NAMEOF ( 'pbi_sales'[Total Sales] ), 0 ),
    ( "Total Profit", NAMEOF ( 'pbi_sales'[Total Profit] ), 1 ),
    ( "Units", NAMEOF ( 'pbi_sales'[Units] ), 2 )
}

Each row is (label, which measure, order). Selecting a label in the slicer tells the chart which measure to use. (Your table name may differ if your measures live in another table.)

For Top N, the numeric range parameter creates a table 'Top N' and a measure [Top N Value]. We add:

Sales Rank = RANKX ( ALL ( pbi_cities[City] ), [Total Sales] )

Top N Sales = IF ( [Sales Rank] <= [Top N Value], [Total Sales] )

• ALL ( pbi_cities[City] ) ranks each city against all cities, not just itself. Mumbai = 1, Pune = 2, Nagpur = 3, Nashik = 4.
• If the rank is within N, return the sales; otherwise return nothing (blank). Visuals hide rows where the measure is blank, so only N bars remain.

Steps

Part A: field parameter

1. Open your file, Save as Lab-21-dynamic, add the Total Profit and Units measures if missing.
2. Click Modeling → New parameter → Fields. (Missing? Turn it on in File → Options and settings → Options → Preview features → Field parameters, then restart.)

3. Name it Metric. From the field list, add Total Sales, Total Profit and Units in that order. Keep Add slicer to this page ticked. Click Create.

   👁 What you should see: a new table Metric in the Data pane and a slicer with three choices on the page.

4. Make a Clustered bar chart: Y-axis pbi_cities[City], X-axis Metric (the field from the Metric table). Turn on data labels.

5. In the Metric slicer, click Total Profit.

   👁 What you should see: Mumbai 88.5K, Pune 69K, Nagpur 53.5K, Nashik 51.5K.

6. Click Units.

   👁 What you should see: Mumbai 32, Pune 24, Nagpur 21, Nashik 18. The axis title changes to Units by itself.

7. In the slicer's Format → Slicer settings → Options, set Style to Tile (or Vertical list) and switch on Single select.

Part B: Top N slider

8. Click Modeling → New parameter → Numeric range. Name Top N, Data type Whole number, Minimum 1, Maximum 4, Increment 1, Default 2. Keep Add slicer to this page ticked. Click Create.

   👁 What you should see: a slider slicer and a table Top N with a measure Top N Value.

9. Add the measures Sales Rank and Top N Sales from the formula box (right-click pbi_sales → New measure).

10. Make a second Clustered bar chart: Y-axis pbi_cities[City], X-axis Top N Sales. Title: Top cities by sales.

    👁 What you should see: with the slider on 2, only Mumbai (439K) and Pune (346K).

11. Move the slider to 3.

    👁 What you should see: Nagpur (260K) appears. At 1, only Mumbai. At 4, all four.

12. Save.

Common mistakes

Self-check checklist

Try-at-home challenge

Make the Top N chart rank by whatever metric is selected in the Metric slicer. Hint: read the selected order number from the Metric table with SELECTEDVALUE and use SWITCH to pick the measure.

Selected Metric Value =
SWITCH ( SELECTEDVALUE ( Metric[Metric Order], 0 ),
    0, [Total Sales], 1, [Total Profit], 2, [Units] )

Metric Rank = RANKX ( ALL ( pbi_cities[City] ), [Selected Metric Value] )

Top N Metric = IF ( [Metric Rank] <= [Top N Value], [Selected Metric Value] )

Samjla ka? A field parameter picks the measure, a numeric range parameter gives N, RANKX with ALL does the ranking. Aata pudhe jaauya: add slicers and sync them across two pages.