C# attribute text from resource file

attributescresources

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 i_Speed;

But I keep getting
"An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type"

It works perfectly if i add a string instead of Data.Messages.Text, like:

[IntegerValidation(1, 70, ErrorMessage = "Invalid max speed")]

Any ideas?

Best Answer

Here is my solution. I've added resourceName and resourceType properties to attribute, like microsoft has done in DataAnnotations.

public class CustomAttribute : Attribute
{

    public CustomAttribute(Type resourceType, string resourceName)
    {
            Message = ResourceHelper.GetResourceLookup(resourceType, resourceName);
    }

    public string Message { get; set; }
}

public class ResourceHelper
{
    public static  string GetResourceLookup(Type resourceType, string resourceName)
    {
        if ((resourceType != null) && (resourceName != null))
        {
            PropertyInfo property = resourceType.GetProperty(resourceName, BindingFlags.Public | BindingFlags.Static);
            if (property == null)
            {
                throw new InvalidOperationException(string.Format("Resource Type Does Not Have Property"));
            }
            if (property.PropertyType != typeof(string))
            {
                throw new InvalidOperationException(string.Format("Resource Property is Not String Type"));
            }
            return (string)property.GetValue(null, null);
        }
        return null; 
    }
}
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