Value Relation widget is very similar to the Value Map tool, but the values for the drop-down menu come from another table (e.g. a CSV or another Geopackage table).
The advantage of having this widget:
Ability to edit the values in the field. For example, if you have missed a value in your list for the drop-down menu, you can edit the table in Input and add the value. See Working with non-spatial tables section for more information.
Ability to search the values: when you have a large list of values, it will become cumbersome to find the right value. With this widget, you will be able to search for values in the list.
Selecting multiple values
To set up a value relation widget:
- Download and open this example project in QGIS
- Notice the extra table in your layer tree: reftable
- From the layer panel, right-click on Points layer and select Properties
- In the new window, select Attributes form
- Select valuerelation field under the right column (Available Widgets)
- Under the Widget Display:
- Under Widget Type section:
- From the drop-down menu, select Value Relation
- For Layer select reftable
- For Key column and Value column, select type
- Check the box for Allow multiple selections
Ensure to save and synchronise your project.
To use the drop-down widget in the form from Input:
- Open Input on your device and from Projects > Explore download lutraconsulting/test_forms
- Open the project
- Select Record and add a point
- The form will appear
- Under Group2 tab, you can select the valuerelation from the drop-down menu: