Question

I’m working on a custom validation framework for my WPF/C# application.

What I’m looking to do is to retrieve strings from the resource file where the viewmodel is declared, but in the actual validation code it self. This particular string is the same resource used by label on the editing UI Form.

My code works fine with the following syntax –

    [Required(TypeRes = typeof(Resources))]
    public string RequiredStringWithDesc { get; set; }

But what I”m looking for is something that is syntacticly cleaner looking. I was trying to use

    const Type LocalRes =  typeof(Resources);
    [Required(TypeRes = LocalRes)]
    public string RequiredStringWithDesc { get; set; }

Any suggestions on a simpler syntax? The old c++ DEFINE statement here would work well.

FYI: the reasons for going to this much work has to do with how we are doing localization and UI construction.

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EDIT To answer a couple of questions about why are we doing this?
We are going to be using the same string from the resource file to –

1. On the edit screen, this is the label to identify the field.
2. In the datamodel, if there is a validation error, we are using this to correctly label the problem in the log file.
3. In the Viewmodel, we are reusing this label in the validation error message to reinforce where the problem is to the user.
4. This is part of a real time inspection system and some of the failure modes relate directly back to these data fields. So we can easily get the correctly localized label to apply to run-time fault messages

The general concept is that this simplifies presenting consistent messages to the user while only creating things once. With regards to validation attributes (and this question), we need to be able to get the Resource file type to load the correct message.

Answer 1

Create a new attribute class which inherits from the RequiredAttribute and set default values.

public class LocalizedRequiredAttribute : RequiredAttribute {
    public LocalizedRequiredAttribute() { /* TypeDef = typeof(Resources);*/ }
}

public class MyModel {
    [LocalizedRequired]
    public string RequiredStringWithDesc { get; set; }
}