Power Platform Community Forum Thread Details

This message is not to ask for help, but to provide a tutorial on how to setup cascading combo boxes in an edit form with a SharePoint list as the data source. I created an app for this, however, using a customized Power App form should also work. This is not a new thing, but it took me months to figure it out. The following provides instructions on setting up cascading combo boxes with a State and City column. I included notes on some steps because I've noticed the formulas are slightly different when I am on my own tenant versus the tenant for my organization.

Drop down boxes are easier to configure for this, but I can't search with a drop down box.

Cascading combo box instructions (naming convention for lists, columns, data cards, etc. can be whatever you want):

Create a list to act as the lookup list and then create another list that will use the cascading combo boxes. Example:
1. List 1 - lookup list with State and City columns (both single line of text fields)
2. List 2 - Second list with Employee info including their state and city as single line of text fields
Create a Power App and attach list 1 and list 2
Create the app with a gallery, edit form, and set the data source to List 2 (create display form if desired)
On the List 2 Edit Form, click on the State_DataCard, unlock it, click on DataCardValue, delete it, then add a combo box and select the List1 data source. Repeat these steps for the City_DataCard.
Rename combo boxes to CbxState and CbxCity
CbxState:
1. Update the Y ErrorMesage with the “CbxState.Y + CbxState.Height” or use a custom value
2. Items: Sort(Distinct(List1, State), Value)
  1. Note: Use the system name for the State column if there is an error.
3. DefaultSelectedItems: {Value:Parent.Default}
  1. Note: Use {Value:Parent.Default} if field is blank when viewing an existing item on the edit form)
4. OnChange: Reset(CbxCity)
  1. Note: be sure this is resetting the city and not the state combo box
5. State_DataCard - Update: CbxState.Selected.Value
6. DisplayFields: [“State”]
  1. Note 1: do not copy and paste this… type it in
  2. Note 2: This property may revert back to [“Value”] on its own
7. SearchFields: [“State”]
  1. Note 1: do not copy and paste this… type it in
  2. Note 2: This property may revert back to [“Value”] on its own
CbxCity:
1. Update the Y ErrorMessage with the “CbxCity.Y + CbxCity.Height” or use a custom value
2. Items: With({wState:CbxState.Selected.Value},Filter(List1,State = wState))
3. DisplayFields: [“City”]
4. SearchFields: [“City”]
5. DefaultSelectedItems: If(ThisItem.State = CbxState.Selected.Value, LookUp(List1, City = ThisItem.City))
6. City_DataCard – Update: CbxCity.Selected.City
Test the app after populating List 1 with a few states and cities