Combo box in Power Apps: flexible selection control

Introduction to Power Apps Combo Box Control

The Combo box control in Microsoft Power Apps is a flexible and powerful selection tool used in canvas applications. It lets users search, filter, and pick one or more items from a list or data source. The Combo box goes beyond what a simple dropdown can do—think about situations where you need to search through a long list, allow multiple choices, or connect to various data sources like SharePoint Online, Dataverse, and Office 365 Users. With this control, app makers can make their forms and data entry screens much more user-friendly, especially when dealing with big or constantly changing datasets.

In many enterprise environments, data sources are always updating or include thousands of records. That’s where the Combo box shines. When you connect it with other Microsoft Power Platform services like Power Automate and Power BI, it becomes a key part of streamlining business processes and automating different workflows. By taking advantage of the Combo box, organizations can build apps that keep up with business changes, handle complex selection needs, and offer a modern, accessible interface for all users.

Core Functionality and Key Properties

The Combo box control brings together the best of dropdown lists and search boxes. You can display a list of items, let users filter as they type, and support both single and multiple choice scenarios.

Key properties:

• Items: Sets where the Combo box gets its data.
• SearchField: Decides which data fields are searched when users type.
• SelectMultiple: Lets you choose if one or more items can be picked.
• DefaultSelectedItems: Shows which items are selected by default when the app loads.
• IsSearchable: Turns the search feature on or off.

These properties give you a lot of control over how people use the Combo box and how information is shown and managed inside your app.

Other helpful properties include DisplayFields and Layout, which let you show extra details or images next to each item. For example, if you’re building a people picker, DisplayFields can show a user’s name and email, and Layout can display their profile picture. The Power Fx formula language is often used to set up Items and DefaultSelectedItems, making it possible to filter data on the fly or set defaults based on who’s using the app or what they picked before.

Modern vs Classic Combo Box Controls

For organizations looking to leverage the full potential of the Combo box control, integrating it with power platform consulting services can seamlessly enhance app functionalities. By collaborating with experienced Power Platform consultants, businesses can optimize user experiences and streamline complex business operations.

You’ll find two types of Combo box controls in Power Apps: classic and modern.

The modern Combo box brings improved performance, a fresh visual look, and new properties. It’s better equipped to handle large datasets, offers stronger delegation support, and is designed for a smoother experience—especially on mobile devices.

With the modern Combo box, you get properties like IsSearchable and improved DefaultSelectedItems, which make it easier to handle business scenarios that can get a bit complex. Accessibility is also front and center, so users who rely on screen readers or keyboards are supported. Plus, Microsoft keeps this version updated as part of their ongoing Power Platform improvements.

The classic Combo box is still available for older apps, but it doesn’t have some of the latest features or optimizations. For new projects or updates, it’s a good idea to go with the modern Combo box for more reliability and flexibility.

Data Source Integration and Setup

The Combo box control can connect to a wide variety of data sources. Common ones include SharePoint lists, Dataverse tables, and the Office 365 Users directory.

Setup typically involves:

• Picking your data source
• Configuring the Items property
• Choosing the right fields for display, search, and selection

For instance, to connect a Combo box to a SharePoint list, set the Items property to your list’s name. To display user profiles from Office 365, set it up so users can search by name or email. For custom collections, fill the Combo box with static or dynamic data.

If you’re integrating with Dataverse, you can take advantage of its rich data types and relationships, which lets you create advanced features like cascading Combo boxes (where one Combo box filters the options in another). In industries like healthcare or finance, using secure sources like Dataverse helps you stay compliant with regulations such as HIPAA or GDPR.

Single and Multiple Selection Implementation

Combo box controls let you pick either one item or several, depending on how you set the SelectMultiple property.

• Single selection: Users can only pick one item. Use the Selected property to get the chosen record.
• Multiple selection: Users can pick as many as needed. The control shows checkboxes or other indicators, and you use the SelectedItems property to get all selections.

This flexibility is great for things like category filters, tag pickers, or assigning tasks to users. For example, in a project management app, you might assign several team members to a task with multiple selection. In an inventory system, you might only want to pick one product at a time using single selection.

Search and Filtering Capabilities

One of the best features of the Combo box is its search and filtering. When IsSearchable is on, users can start typing, and the list will instantly narrow down to matching items. The SearchField property lets you pick which fields are searched.

If your data source supports delegation, like SharePoint or Dataverse, search is handled on the server. This is especially important for large datasets, since you don’t want to slow down your app by loading everything at once. Instead, users see only the results that matter to them, keeping things fast and efficient.

You can also set up multiple search fields or add custom filtering logic with Power Fx formulas. For example, in a CRM app, let users search for clients by either name or company. By including both fields in SearchField, users can find what they need even if they only remember part of the information.

Performance Optimization for Large Datasets

If you’re dealing with big datasets, performance is key. The Combo box leverages the Power Apps delegation framework, which means queries are processed on the server instead of on each user’s device. This keeps your app responsive, even when searching or filtering millions of records.

Tips for optimizing performance:

• Use delegable data sources and operations
• Set up SearchField and Items for server-side filtering
• Avoid non-delegable formulas
• Show only a subset of records based on user input
• Check for delegation warnings in Power Apps Studio and adjust queries as needed

In regulated industries, server-side delegation is not just about performance—it’s also about security. By filtering data on the server, you reduce the risk of exposing sensitive information on devices, helping your organization stay compliant with standards such as SOC 2 or HIPAA.

Combo Box vs Dropdown: Complete Comparison

Combo box is the way to go if you expect long lists, need users to search or pick more than one item, or want to customize how items look. Dropdown is better for short, static lists where users just need to pick one option and search isn’t necessary.

For example, an HR app that lets you select employees from a big directory is a perfect fit for Combo box. But if you’re just picking a department from a short list, Dropdown might be all you need. Microsoft’s documentation and Power Platform community forums have plenty of charts and guides to help you decide.

Advanced Features and Configuration Options

Combo box controls come with a range of advanced features for those who need extra flexibility:

• Custom layouts: Show more details or images next to each item (great for people pickers)
• Multi-field search: Users can find items by more than one attribute, such as both name and email
• DefaultSelectedItems: Pre-select items based on user context or app logic
• Conditional formatting and custom validation: Use Power Fx formulas to change appearance or behavior based on input or business rules
• Event triggers: Update other parts of your app or submit data when a selection changes
• NoMatchText: Show a custom message if no results are found
• OnChange event: Kick off automated workflows in Power Automate
• AllowFreeFormInput: Let users type in values not found in the list (if available)

People Picker Implementation Guide

A popular use for the Combo box is as a people picker, especially when you connect it with the Office 365 Users connector. This lets users search for and select people from the company directory, showing details like names, emails, and even profile pictures.

To set up a people picker:

• Connect the Combo box to Office 365 Users as your data source
• Use a formula for the Items property to pull user data
• Set SearchField to include fields like displayName and mail
• Pick a layout that shows both text and images
• Allow single or multiple user selection as needed

Optimize performance by limiting the number of results and using search-as-you-type. For example, in an internal help desk app, a Combo box can make it easy to assign tickets to colleagues by searching the whole directory. With the modern Combo box and a carefully designed Items formula, you can keep response times quick and user experience positive—even with tens of thousands of users.

Troubleshooting Common Issues

You might run into a few common issues with Combo box controls:

• Delegation warnings: A query can’t be processed on the server and may return incomplete results. Adjust your formula to use delegable operations.
• Unexpected OnChange triggers: The event fires when DefaultSelectedItems is updated programmatically rather than by the user. Add logic to tell the difference between system changes and user actions.
• Performance problems: Often caused by non-delegable queries, complex item layouts, or loading too many records at once. Stick with delegable operations, simplify layouts, and limit the amount of data shown.
• Data refresh: Use the Refresh function in Power Fx to keep the Combo box up to date when the data source changes. Make sure your data refreshes and user selections align with your organization’s audit and IT security policies.

Best Practices and Optimization Tips

• Prefer the modern Combo box for new apps to enjoy better performance and user experience.
• Always use delegable data sources and operations for handling large datasets.
• Limit the number of displayed items by using search-as-you-type.
• Set SearchField to target the fields that matter most.
• Use DefaultSelectedItems to pre-populate choices when it makes sense.
• Keep an eye on delegation warnings and adjust your formulas as needed.
• Test your Combo box on different devices and with varying data sizes to ensure consistent performance.
• Document your Combo box settings and any custom Power Fx formulas.
• Stay connected with the Microsoft Power Platform Community for updates and best practices.
• Follow security guidelines and privacy rules to make sure Combo box selections don’t accidentally reveal sensitive information.

Frequently Asked Questions

What is the difference between a combo box and dropdown in Power Apps?

Combo box supports search, multiple selection, and advanced customization, while dropdown is limited to single selection and basic lists.

How do I enable multiple selection in a Power Apps combo box?

Set the SelectMultiple property to true. The control will then allow users to select more than one item.

Can combo boxes handle more than 500 items in Power Apps?

Yes, but you need to use delegable data sources and operations. Adjust delegation limits as needed and use server-side filtering.

How do I connect a combo box to a SharePoint list?

Set the Items property to your SharePoint list’s name and configure the display and search fields accordingly.

Why is my combo box OnChange event triggering unexpectedly?

This can happen when DefaultSelectedItems is updated programmatically. Add logic to distinguish between user and system changes.

What are delegation warnings and how do I fix them?

Delegation warnings mean a query can’t be processed on the server and may return incomplete results. Use delegable operations and review Power Apps Studio warnings.

How do I implement search functionality in a combo box?

Enable the IsSearchable property and set the SearchField property to the fields you want users to search.

Can I use a combo box as a people picker in Power Apps?

Yes, by connecting the Combo box to the Office 365 Users data source and configuring the layout for people data.

What’s the difference between modern and classic combo box controls?

Modern Combo box offers better performance, more features, and improved accessibility compared to the classic version.

How do I set default selected items in a combo box?

Use the DefaultSelectedItems property and set it with a formula or value based on your app’s logic.

Why is my combo box performing slowly with large datasets?

Performance issues are often due to non-delegable queries or loading too many records. Use server-side filtering and delegable operations.

How do I filter combo box items dynamically based on user input?

Use Power Fx formulas in the Items property to filter data based on other controls or user actions.