CODEWITHSUNDEEP
c#validationdata-annotations
Zoltán Tamási
Zoltán Tamási

Reputation: 12764

How to change the default error message of built-in ValidationAttributes?

I would like to replace the default error message for for example RequiredAttribute or RegularExpressionAttribute with my own messages, so that I wouldn't need to specify the explicit ErrorMessage at attribute usage.

EDIT: Last part of the sentence means that I'm aware of the ability to specify my own ErrorMessage at attribute usage, and I would like to avoid it for keeping the project DRY.

Is it possible somehow? I haven't found any related property in the .NET library, and I currently have no idea how I could replace the .NET resources where the default messages are stored.

Upvotes: 1

Views: 997

Answers (1)

ryanyuyu
ryanyuyu

Reputation: 6486

Just create your own version of the [Required] attribute that has a default message that you want. If you only want to use a custom error message have it inherit from RequiredAttribute so you can take advantage of the same IsValid logic

public class MyRequired : RequiredAttribute
{
    public MyRequired()
    {
        this.ErrorMessage = "Custom Validation Error Message.";
    }
}

If you need even finer control over other validation behaviors, you can create your own DataAnnotation Attributes. 

public class MyRequired : ValidationAttribute
{
    public MyRequired() : base("My Custom Message")
    {

    }

    public override bool IsValid(object value)
    {
        //Your custom validation logic
        return (value != null);
    }
}

Upvotes: 1

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