How to refresh localized attributes in PropertyGrid

Question

I have problem with my localized attributes such as:

public class LocalizedDisplayNameAttribute : DisplayNameAttribute
{
    public LocalizedDisplayNameAttribute(string resourceId)
        : base(GetMessageFromResource(resourceId))
    { }

    private static string GetMessageFromResource(string resourceId)
    {
        var propertyInfo = typeof(Lockit).GetProperty(resourceId, BindingFlags.Static | BindingFlags.Public);
        return (string)propertyInfo.GetValue(null, null);
    }
}

When I'm using properties with this attribute it's localized in PropertyGrid, but when I change the current CultureInfo it doesn't refresh, even if I create this PropertyGrid again. I've try to manually call this attribute by:

foreach (PropertyInfo propertyInfo in myPropertiesInfoTab)
{
    object[] custom_attributes = propertyInfo.GetCustomAttributes(false);
}

The property constructor is called, but the newly created PropertyGrid still has the property for the old culture display name (always the same value as first created).

It works when I restarting application, but I don't want to do this. Is there any solution?

Answer 1

We can reproduce this in a simple but complete example (that simply adds a counter onto the name, to represent each translation as it happens):

[STAThread]
static void Main()
{
    Application.EnableVisualStyles();
    Show();
    Show();
}
static void Show()
{
    using(var grid = new PropertyGrid
        {Dock = DockStyle.Fill, SelectedObject = new Foo { Bar = "def"} })
    using(var form = new Form { Controls = { grid }})
    {
        form.ShowDialog();
    }
}

class Foo
{
    [CheekyDisplayName("abc")]
    public string Bar { get; set; }
}
public class CheekyDisplayNameAttribute : DisplayNameAttribute
{
    public CheekyDisplayNameAttribute(string resourceId)
    : base(GetMessageFromResource(resourceId))
    { }
    private static string GetMessageFromResource(string resourceId)
    {
        return resourceId + Interlocked.Increment(ref counter);
    }

    private static int counter;
}

This demonstrates that the attribute is being cached between calls. Perhaps the easiest way to fix this is to delay the translation to the time that DisplayName is queried:

public class CheekyDisplayNameAttribute : DisplayNameAttribute
{
    public CheekyDisplayNameAttribute(string resourceId)
        : base(resourceId)
    { }
    private static string GetMessageFromResource(string resourceId)
    {
        return resourceId + Interlocked.Increment(ref counter);
    }
    public override string DisplayName
    {
        get { return GetMessageFromResource(base.DisplayName); }
    }
    private static int counter;
}

However, note that this can be called lots of times (36 per showing); you might want to cache the value along with the culture it was cached for:

    private CultureInfo cachedCulture;
    private string cachedDisplayName;
    public override string DisplayName
    {
        get
        {
            var culture = CultureInfo.CurrentCulture;
            if (culture != cachedCulture)
            {
                cachedDisplayName = GetMessageFromResource(base.DisplayName);
                cachedCulture = culture;
            }
            return cachedDisplayName;
        }
    }