RequiredIf conditional attribute in .net Core

UoN.ExpressiveAnnotations.NetCore is the package used for .NET Core applications same functionality as ExpressiveAnnotation package for MVC

Reference URL: https://github.com/uon-nuget/UoN.ExpressiveAnnotations.NetCore

You can extend RequiredAttribute to check the property value and according to that manually check IsNullOrWhiteSpace of current property .

You can find the code sample here . Here is another code sample using custom ValidationAttribute .