I have two blocks like maste and detail.
In some filed of master i added mandatory filed validation like below.
IF :BLOCK.ITEM IS NULL THEN
MESSAGE('Must be entered');
MESSAGE('Must be entered',NO_ACKNOWLEDGE);
While saving these validations firing. But my problem is without entering these details when i go to detail block these validations not firing. This problem is coming only for some forms which i developed new. For old forms when i go to detail block without entering the master block filed it is giving message. For this need to set any setting.
If its WHEN-VALIDATE-ITEM, forms won't invoke the validation if you did not enter anything in the field. Why don't you use the standard validation and set the field to required? Then there is no need for your trigger.
If you want to user must input a value in your item then set the required property of that item to yes. If your looking for something else you can use when-validate-item trigger on that item. If you want execute some after or before navigation to other block use when-new-block instance trigger.