WPF Binding : Use DataAnnotations for ValidationRules

Question

I have read a lot of Blog post on WPF Validation and on DataAnnotations. I was wondering if there is a clean way to use DataAnnotations as Va

Answer 1

The closest approach I found is :

// This loop into all DataAnnotations and return all errors strings
protected string ValidateProperty(object value, string propertyName)
{
  var info = this.GetType().GetProperty(propertyName);
  IEnumerable errorInfos =
        (from va in info.GetCustomAttributes(true).OfType()
         where !va.IsValid(value)
         select va.FormatErrorMessage(string.Empty)).ToList();


  if (errorInfos.Count() > 0)
  {
    return errorInfos.FirstOrDefault();
  }
  return null;

Source

public class PersonEntity : IDataErrorInfo
{

    [StringLength(50, MinimumLength = 1, ErrorMessage = "Error Msg.")]
    public string Name
    {
      get { return _name; }
      set
      {
        _name = value;
        PropertyChanged("Name");
      }
    }

public string this[string propertyName]
    {
      get
      {
        if (porpertyName == "Name")
        return ValidateProperty(this.Name, propertyName);
      }
    }
}

Source and Source

That way, the DataAnnotation works fine, I got a minimum to do on the XAML ValidatesOnDataErrors="True" and it's a fine workaround of Aaron post with the DataAnnotation.