C# attribute text from resource file?

Question

I have an attribute and i want to load text to the attribute from a resource file.

[IntegerValidation(1, 70, ErrorMessage = Data.Messages.Speed)]
private int         


        

Answer 1

Here is the modified version of the one I put together:

[System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple = false)]
public class ProviderIconAttribute : Attribute
{
    public Image ProviderIcon { get; protected set; }

    public ProviderIconAttribute(Type resourceType, string resourceName)
    {
        var value = ResourceHelper.GetResourceLookup<Image>(resourceType, resourceName);

        this.ProviderIcon = value;
    }
}

    //From http://stackoverflow.com/questions/1150874/c-sharp-attribute-text-from-resource-file
    //Only thing I changed was adding NonPublic to binding flags since our images come from other dll's
    // and making it generic, as the original only supports strings
    public class ResourceHelper
    {
        public static T GetResourceLookup<T>(Type resourceType, string resourceName)
        {
            if ((resourceType != null) && (resourceName != null))
            {
                PropertyInfo property = resourceType.GetProperty(resourceName, BindingFlags.Public | BindingFlags.Static | BindingFlags.NonPublic);
                if (property == null)
                {
                    return default(T);
                }

                return (T)property.GetValue(null, null);
            }
            return default(T);
        }
    }

Answer 2

Attribute values are hard-coded into the assembly when you compile. If you want to do anything at execution time, you'll need to use a constant as the key, then put some code into the attribute class itself to load the resource.

Answer 3

If you're using .NET 3.5 or newer you can use ErrorMessageResourceName and ErrorMessageResourceType parameters.

For example [Required(ErrorMessageResourceName ="attribute_name" , ErrorMessageResourceType = typeof(resource_file_type))]