Validation between two dates in a Register

[GregJohnson]

Is it possible to put a validation rule on the register to ensure the EndDate field (|DCode2) is greater than the StartDate field({Dcode1|}?  I have date math occurring as below:
XFBR(TLP_ParamHelper, GetTimeSpan,D1=|DCode1|,D2=|DCode2|,Type=M)

My register calculation generates and error if the date math results in a zero.  I would like to do this check upon entering values in the register or upon SAVE.

[LeeB]

Yes, you need to use the Custom Event Model which contains Save Register Rows event handler.

It will validate the rows before save to ensure they meet the conditions you've defined.

An example shown here...