How to clear a selection when using Dependent drop-downs

[gcor71]

I have followed the Appsheet Help https://support.google.com/appsheet/answer/10106620?sjid=16052846088463009199-EU to successfully create a dependent drop-down using Valid_If constraints.

• Field 1 - select a Group (1st Portsmouth, 3rd Portsmouth etc)
• Field 2 - dependent on Field 1, select a Section (for 1st Portsmouth: options are Squirrels, Beavers, Cubs; for 3rd Portsmouth: options are Cubs, Scouts, Explorers).  All defined in a GROUP_SECTION_DATA table.

This works as expected, except if I have make a selection in Field 2 then change Field 1 to a Group where that selection is not valid.  For example: 1st Portsmouth, Squirrels & Cubs is selected.  Change to 3rd Portsmouth, Cubs remains selected but so does the (now hidden) Squirrels choice.  This means the field is invalid.

How to clear an invalid Field 2 selection when Field 1 changes?  (It does not need to remember the prior selection if the user switches back to the previous selection in Field 1.)

Or alternatively, how to clear all Field 2 choices when Field 1 changes?

Thanks in advance

[WillowMobileSys · Accepted solution]

Unfortunately, once a user has chosen a value, there is not a way to "clear" the selected value.  However, if you have implemented the drop-down choices in the Valid_If, this list acts as a validation. 

If a user had selected a value that was valid but then the drop-down list changes making that chosen value invalid.  The Form view will not allow the user to Save until a valid value is chosen OR is manually cleared by the user.