Display regular expression correct error messages

Question

I have a regular expression data annotation:

[StringLength(100)]
[Display(Description = "Password")]
[RegularExpression(@^((?=.*[a-z])(?=.*[A-Z])(?=.*\d)).+$)], ErrorMessage = " must include at least one upper case letter,one lower case letter and one numeric digit")]
public string Password { get; set; }

How can I display an Error Message based on the reason the validation failed?

If the password is 12345678 then tell the user he didn't include at least 1 upper case and 1 lower case.

If the password is abcdefgH then the Error message will be:"must insert at least 1 digit".

Søren Fritzbøger · Accepted Answer · 2016-03-10 18:25:35Z

1

One way this could be done is to create your own regex validation attributes. You can extend the RegularExpressionAttribute and thereby seperate the different parts of your regex:

public class UpperAndLowerCaseAttribute : RegularExpressionAttribute
{
    public UpperAndLowerCaseAttribute()
        : base("**YOUR REGEX HERE**")
    {
    }
}

You can then use it like so:

[UpperAndLowerCaseAttribute, ErrorMessage = "ERRORMESSAGE"]
public string Password { get; set; }

answered Mar 10, 2016 at 18:25

Søren Fritzbøger

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3 Comments

Søren Fritzbøger Over a year ago

It doesn't work in the view using unobtrusive validation, but i believe it should work for server side validation

Offir Over a year ago

My unobtrusive validation works except this one. That doesn't work also after the submit.

Offir Over a year ago

I had to add in my global.asax this: DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(UpperAndLowerCaseAttribute), typeof(RegularExpressionAttributeAdapter));

Offir · Accepted Answer · 2016-06-23 06:29:41Z

0

My custom class:

public class UpperAndLowerCaseAttribute : RegularExpressionAttribute
{
    public UpperAndLowerCaseAttribute()
        : base("**YOUR REGEX HERE**")
    {
    }
}

How to use it:

[UpperAndLowerCaseAttribute, ErrorMessage = "ERRORMESSAGE"]
public string Password { get; set; }

Add this to the global.asax to get recognized in client side:

DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(UpperAndLowerCaseAt‌tribute), typeof(RegularExpressionAttributeAdapter));

answered Jun 23, 2016 at 6:29

Offir

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