Validate Cell Based on Content of Another Cell

I am trying to validate a Cell(Job Notes - Editable Type) only when another cell(isReDo? - CheckBox Type) is selected.

The Validation only needs to ensure that there are at least 20 characters in the job notes box whenever the is redo checkbox is ticked.

how would I go about doing this?

My data processor should not write changes to the database unless all validation passes.

Any help would be greatly appreciated.

You may try to use the following solution:

myDataProcessor.setVerificator(13,your_rule)

function your_rule(value,id,ind){
if (myGrid.cellById(id,12).getValue()==“1”){ //if checkbox is checked
// your validation rule
}
else
return true //ignore the validation if the checkbox is not checked
}