Check Quantity with only one decimal place

Hi everybody,

we have a Quantity field in our xbo.

This is already deployed and until now everything was fine with this field.

Now the customer has a new requirement: There should only one decimal place possible in this field.

How can I archive this?

Is there something like

[Decimal (3,1)] element Decimal: DecimalValue;

for Quantity?

Or a method to check the decimals in the BeforeSave Validation?

I want to avoid create a new field, as we are replicate this one and would have to rearrange the mapping.

Thanks for your help.

Astrid