Custom Multi-Select Checkbox with Gallery in Power Apps Forms

In many business applications, users need to pick more than one value from a set of options. While Power Apps offers the combo box for multiple selections, sometimes a checklist-style interface is more intuitive or required by design. This article walks through building a custom multi-select checkbox control by combining a gallery with individual checkboxes, and correctly saving the selections back to a SharePoint list.

Our example scenario is a Task Assignment Manager – a project management tool where each task can require multiple competencies (Design, Development, Testing, DevOps). The SharePoint list ProjectTasks stores these competencies in a multi‑select choice column.

Creating the SharePoint List

Create a new SharePoint list named ProjectTasks and add the following columns:

• Title (single line of text)
• Due Date (date)
• Estimated Hours (number)
• Competencies Required (choice, with Allow multiple selections enabled)

Add four choice values: Design, Development, Testing, and DevOps. Populate the list with a few sample rows so you have data to work with.

Setting Up the App Canvas

Open Power Apps Studio and create a canvas app from blank. Insert a data source connected to the ProjectTasks list, then add an Edit form. Configure the form’s DataSource and set its DefaultMode to FormMode.New.

The form automatically exposes all four columns. Locate the Competencies Required card – it shows a Combo box control by default. Delete that combo box and expand the card’s height to leave room for a gallery.

Building the Multi‑Select Checkbox Gallery

Inside the Competencies Required card (not inside the gallery), insert a Blank vertical gallery. Write the following code in its Items property to pull the list of all possible options:

Choices('ProjectTasks'.'Competencies Required')

Now add a Checkbox control (from the Input menu) inside the gallery. Set its Text property to:

ThisItem.Value

Resize the gallery so all checkboxes fit inside the card.

Tracking Selections with a Collection

Select the checkbox inside the gallery. Use its OnCheck and OnUnCheck properties to manage a collection named colSelectedCompetencies.

OnCheck – add the selected value to the collection:

Collect(colSelectedCompetencies, ThisItem.Value)

OnUnCheck – remove the unchecked value:

RemoveIf(colSelectedCompetencies, Value = ThisItem.Value)

Because the gallery contains only one checkbox template, these formulas apply to every row dynamically.

Connecting the Checkbox Selections to SharePoint

The Update property of the card determines what data is written to SharePoint when the form is submitted. Select the Competencies Required card (the entire card, not the gallery) and set its Update property to:

colSelectedCompetencies

Any error shown on the card will now disappear. You can optionally delete the ErrorMessage label inside the card; it is not needed for this pattern.

Submitting the Form

Place a Button below the form and set its OnSelect to:

SubmitForm(Form_NewTask)

To keep the form in a clean state after submission, store the last submitted record and switch to view mode. Use the form’s OnSuccess property:

Set(varCurrentTask, Form_NewTask.LastSubmit);
ViewForm(Form_NewTask);

Then set the form’s Item property to varCurrentTask so it displays the submitted record in read‑only mode.

Loading Existing Selections Back into the Checkboxes

When an existing record is opened for editing, the checkboxes must reflect the values already stored. Create a browse screen with a gallery connected to the ProjectTasks list. Write the following code in the OnSelect of that gallery (or a navigation button) to load the record and populate the collection:

Set(varCurrentTask, ThisItem);
ClearCollect(colSelectedCompetencies, varCurrentTask.'Competencies Required');
EditForm(Form_NewTask);
Navigate('Edit Task Form');

Now return to the checkbox inside the edit form’s gallery. Set its Default property to the following expression – this tells each checkbox whether it should appear checked:

ThisItem.Value in colSelectedCompetencies.Value

Test the flow: navigate from the browse screen to an existing record; the correct checkboxes are already selected.

Performance and Delegation Notes

The Choices function returns at most 2000 options, which is more than enough for typical choice columns. The collection and gallery logic run entirely on the client, so there is no delegation bottleneck. For very large choice lists (seldom needed), consider limiting the number of options or using a different data source.

Common Mistakes to Avoid

• Forgetting to clear the collection before loading existing values. Always use ClearCollect instead of Collect when populating from an existing record to avoid duplicate entries.
• Omitting the card’s Update property. Without this, the form will not pass the selected values to SharePoint, and the data will be lost.
• Using the wrong Default syntax. The expression ThisItem.Value in colSelectedCompetencies.Value must be written exactly this way – note the .Value on both sides.

Final Recommendation

The multi‑select checkbox gallery gives you full control over the appearance and behavior of your form’s choice fields. It is ideal when you need a checkmark‑style picker, particularly in forms that already use galleries or require inline selection. For straightforward single‑selection needs the combo box remains a fine choice, but whenever you want a clear, user‑friendly multi‑pick interface without leaving the gallery pattern, this approach is both flexible and reliable.

References

• Original inspiration: Matthew Devaney, Power Apps Multiple Selection Checkbox
• Microsoft Learn: Choices function
• Microsoft Learn: Collect and ClearCollect functions