How to Create a Cascaded Lookup Column in SharePoint Out-of-the-box SharePoint does not natively support cascaded (dependent) lookup columns. When managing complex data structures—such as selecting a Country and needing the State dropdown to dynamically filter—standard lookup fields show all items regardless of previous selections.
To build true cascading lookups, administrators must rely on modern workarounds like Microsoft Power Apps, customized modern forms via third-party extensions, or legacy client-side scripting. Method 1: The Modern Standard (Microsoft Power Apps)
The most robust, future-proof, and Microsoft-supported method to create a cascading dropdown utilizes Power Apps to customize the SharePoint list form [0.5.1”]. Step 1: Set Up Your Source Data Lists
Before building the form, you must structure your underlying SharePoint lists to establish relationships. Create three custom lists:
Countries: Use the default Title column to add your parent values (e.g., USA, Canada). States:
Add a standard Lookup column named Country pointing to the Countries list.
Use the Title column for the state name (e.g., California linked to USA). Main Data List (e.g., Requests): Add a Lookup column pointing to Countries. Add a second Lookup column pointing to States. Step 2: Customize the List Form in Power Apps Navigate to your Main Data List.
Click Integrate in the top ribbon, hover over Power Apps, and select Customize forms.
Power Apps Studio will load your default SharePoint form layout. Step 3: Write the Filter Formula
To make the State field change dynamically based on the Country field, you must alter its data source property.
Select the DataCardValue (the dropdown control) inside the State card.
In the properties panel on the right, click the Advanced tab and select Unlock to change properties.
Find the Items property in the formula bar (it defaults to Choices([@‘Main Data List’].State)).
Replace it with a Filter expression that limits choices based on the selected Country ID:
Filter(States, Country.Id = DataCardValue_Country.Selected.Id) Use code with caution.
(Note: Replace DataCardValue_Country with the exact control name of your parent Country dropdown). Step 4: Configure the Card Update Property
To ensure Power Apps submits the correct data back to SharePoint, verify the parent data card structure:
Select the entire State DataCard (not just the dropdown inside it). Look at its Update property in the formula bar. Ensure it outputs a proper lookup record format:
{ Id: DataCardValue_State.Selected.ID, Value: DataCardValue_State.Selected.Title } Use code with caution. Click File > Save, then click Publish to SharePoint. Method 2: Third-Party Form & Column Extensions
If you prefer to keep users entirely within the native SharePoint list interface without redirecting them to a Power Apps layout, third-party column enhancements offer a non-code alternative.
How to create a Cascaded Lookup as a site column – BoostSolutions
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