Writing XML to have Interdependent Require Fields

Writing Interdependent Required Fields

Where either one field or another (but only one field) must be filled in.

A condition for each of the fields to determine if it is empty:

       <Condition no_cache="true">
         <ZName>XXX_not_present_condition</ZName>
         <DisplayName>XXX should be entered</DisplayName>
         <Field>
           <ZName>XXXXX</ZName>
         </Field>
         <Test>Equals</Test>
         <DesiredValue>
           <StaticValue></StaticValue>
         </DesiredValue>
       </Condition>
             
             

Validation to ensure at least one of the fields is populated:

     <Validation class="Value">
       <ZName>XXX_validation</ZName>
       <DisplayName>XXX or YYY must be entered</DisplayName>
       <ClassOptions>
         <Required>true</Required>
       </ClassOptions>
       <PassOnConditionFail>true</PassOnConditionFail>
       <Condition>
         <ZName>XXX_not_present_condition</ZName>
       </Condition>
     </Validation>
     

Conditional Format to hide the 'opposite' field when one field is populated

         <ConditionalFormat>
           <ZName>XXX_hide_cf</ZName>
           <classes>zz_disabled</classes>
           <DisableInputs>true</DisableInputs>
           <Condition>
             <ZName>XXX_present_condition</ZName>
             <Base>XXX_not_present_condition</Base>
             <Test>NotEqual</Test>
           </Condition>
         </ConditionalFormat>

Note that there is a generic class to hide things in the main CSS (hidden) - however, using it rather than just disabling the inputs causes the other fields to move around and is not ideal.

Add a ShortDescription to each field explaining that the other field can be shown by clearing 'this' one.