Data Annotations make a value Required when another model value is not empty?
65140
RequiredIf Conditional Validation Attribute
18681
Error: j_id0:j_id1:j_id28:j_id30: Validation Error: Value is required
83357
Validating required selection in DropDownList
107530
How to tell whether a field is required or not in Apex by describe fields
144544
How to handle NULL values when inserting with the Dataloader(.io)
31827
Any way to make {% extends '...' %} conditional? - Django
33613
Why is this trigger finding a null value despite the field being populated?
155969
Required Attribute on Generic List Property
80739
How can I check if my model is valid from inside the razor view?
156999
Selectively expand associations in Spring Data Rest response
145867
A required field that isn't really required?
72088
Why shouldn't we allow NULLs?
145489
How to perform entity validation on code level?
11232
The model item passed into the dictionary is of type .. but this dictionary requires a model item of type
40660
Handle null value using Guava MapMaker/CacheBuilder
116537
Model.IsValid always returning true
41165
Foreign key constraints failures