Cascade Lookup in Power Apps Model Driven Applications and Power Pages

In a recent training session, Brian Knight from Pragmatic Works explored how to implement cascading lookups in Power Apps Model-Driven Applications and Power Pages. This feature enhances user experience by ensuring that drop-down selections are filtered logically, avoiding irrelevant or frustrating results.

Why Cascading Lookups Matter

Imagine a user selecting "United States" as a country but still seeing Canadian provinces in the next drop-down, or choosing "Florida" only to see cities from Georgia. Such mismatches lead to confusion and errors. Cascading lookups solve this problem by filtering dependent lists so users only see relevant values based on their first selection.

Initial Setup of Tables

To demonstrate, Brian prepared a simplified model with three tables:

• Product Categories – the parent table (e.g., Cars, Bikes, Planes).
• Service Types – individual services linked to product categories (e.g., Upgrades for Cars, Adjustments for Planes).
• Orders – the table capturing user selections for product categories and services.

The goal was to ensure that when a user selects a product category in the order form, only the matching service types appear in the next lookup field.

Step 1: Creating Lookup Columns

Brian began by creating lookup columns to establish relationships:

1. In the Order table, he added a lookup column referencing Product Category.
2. In the Service Type table, a lookup to Product Category was already in place.

These lookup columns provide the necessary referential integrity to connect parent and child tables.

Step 2: Adding Lookup Fields to the Form

Next, Brian edited the main order form:

• Added the new Product Category lookup column.
• Placed it above the Service Type column for logical data entry.

Initially, without filtering, the service type drop-down displayed all available services regardless of category—a confusing experience for users. To fix this, Brian enabled cascading logic.

Step 3: Configuring Cascading Filters

Inside the form settings for the Service Type column, he:

1. Disabled "Most Recently Used Items" – preventing irrelevant suggestions based on past selections.
2. Applied Filtering – used the “Filter by related rows” option to link Service Type to the selected Product Category.
3. Restricted user override – ensuring users cannot disable the filter and accidentally see unrelated values.

After saving and publishing, Brian demonstrated how choosing “Cars” now filtered the service type list to only display services related to cars. The same applied when selecting “Planes” or “Bikes.”

Step 4: Extending to Power Pages

The cascading lookup functionality also applies to Power Pages. After refreshing the Power Page preview, Brian selected a product category, and only the relevant services appeared. He noted that Power Pages also allow configuring the lookup field as a drop-down for a more compact UI experience.

Advanced Options and Common Questions

Brian addressed a common question: can cascading logic be applied to choice (option set) columns instead of lookup tables? The answer is yes, but it requires JavaScript customization, which adds complexity. For simpler, no-code implementations, storing options in lookup tables is recommended.

Best Practices

Brian summarized cascading lookups in two critical steps:

1. Establish lookup relationships between parent and child tables (e.g., Service Type to Product Category).
2. Add both lookup fields to the child form (in this case, the Order form) and apply filtering.

This approach ensures data integrity, streamlines user input, and creates a more intuitive application.

How Pragmatic Works Can Help

At Pragmatic Works, training goes beyond tutorials. The team provides:

• Hackathons – hands-on workshops to solve real-world problems.
• Virtual Mentoring – personalized guidance when facing roadblocks in Power Apps, Power BI, or Azure projects.
• Expert Training – structured courses designed to elevate skills across Microsoft’s Power Platform and cloud ecosystem.

By applying cascading lookups, developers and business users can significantly improve application usability while maintaining clean data relationships.

Don't forget to check out the Pragmatic Works' on-demand learning platform for more insightful content and training sessions on Power Apps and other Microsoft applications. Be sure to subscribe to the Pragmatic Works YouTube channel to stay up-to-date on the latest tips and tricks.