DataAnnotations Localization Using Default Attributes

DataAnnotations localization setup is already done during the express setup in startup.cs file for razor pages or MVC.

All we have to do is just provide an error message to the relevant attribute or a Name value for Display attribute:

[Required(ErrorMessage = "The {0} field is required.")]
[Display(Name = "Full name")]
public string Name { get; set; }

Default Error Messages

For easy implementation, all default framework error messages of data annotations, model binding and identity errors are predefined under LazZiya.ExpressLocalization.Messages namespace.

So we can use the already defined messages as below:

using LazZiya.ExpressLocalization.Messages

[Required(ErrorMessage = DataAnnotationsErrorMessages.RequiredAttribute_ValidationError)]
[Display(Name = "Full name")]
public string Name { get; set; }

See all DataAnnotationsErrorMessages

Customizing Error Messages

You are still able to provide custom validation messages as below:

[Required(ErrorMessage = "Ooops! The {0} field is necessary to continue...")]
[Display(Name = "Full name")]
public string Name { get; set; }

Notice : depending on ExpressLocalization setup, the error messages must be defined in the relevant resource file for DataAnnotations. For more details see Creating Resources.

Applies to ExpressLocalization versions:

4.0, 3.2, 3.1, 3.0, 2.0, 1.1, 1.0