Feature/auto watermark

[michaelmairegger]

AutoWatermark is able to get the DisplayAttribute from the bound property in following cases:

• Binding that is supported
  • "{Binding Path=Property}"
  • "{Binding Path=Property.SubProperty}"
  • "{Binding Path=CollectionProperty}"
  • "{Binding Path=CollectionProperty[0].SubProperty}"
• Binding that is not supported
  • "{Binding Path=CollectionProperty[0]}"

Tasks

• Searches for WatermarkAttribute on bound property (like stated above)
• Decision: Is property name adequate
• Decision: Should error/warning shown if property does not have DisplayAttribute
• Error must occur if control does not support AutoWatermark

closes #2712

[punker76]

@xxMUROxx We can do this for .Net 4 too, look at this here which works...

        private static void OnControlWithAutoWatermarkSupportLoaded(object o, RoutedEventArgs routedEventArgs)
        {
            FrameworkElement obj = (FrameworkElement)o;
            obj.Loaded -= OnControlWithAutoWatermarkSupportLoaded;

            DependencyProperty dependencyProperty;

            if (!AutoWatermarkPropertyMapping.TryGetValue(obj.GetType(), out dependencyProperty))
            {
                throw new NotSupportedException($"{nameof(AutoWatermarkProperty)} is not supported for {obj.GetType()}");
            }
            var binding = obj.GetBindingExpression(dependencyProperty);

            if (binding != null)
            {
                var dataItem = binding.DataItem.GetType();
#if NET4_5
                var propertyName = binding.ResolvedSourcePropertyName;
#else
                var propertyName = binding.ParentBinding?.Path?.Path;
#endif
                if (propertyName != null)
                {
                    var property = dataItem.GetProperty(propertyName, BindingFlags.GetProperty | BindingFlags.Public | BindingFlags.Instance);
                    if (property != null)
                    {
#if NET4_5
                        var attribute = property.GetCustomAttribute<WatermarkAttribute>();
#else
                        var attribute = property.GetCustomAttributes(typeof(WatermarkAttribute), false).FirstOrDefault() as WatermarkAttribute;
#endif
                        if (attribute != null)
                        {
                            obj.SetValue(WatermarkProperty, attribute.Caption);
                        }
                    }
                }
            }
        }
#endif

But we must make a note to the users, that this feature uses reflection, which can have performance issues if you use this on many controls with watermark in a UI.

[punker76]

By the way, can you revert the Xaml style changes? Thx

[punker76]

Possible memory leak...

[michaelmairegger]

Because of the event subscription? Shouldn't it be enough to unsubscribe directly after the event was raised the first time?

[punker76]

Why is it necessary to introduce a new attribute? Is the Display attribute too bad?

[michaelmairegger]

No, of course, it is not.

[michaelmairegger]

@punker76 XAML-Style change was introduces unintentionally. I will revert them

[michaelmairegger]

@punker76 reverted xaml, added .net4 support and hopefully removed memory leak

[punker76]

@xxMUROxx It seems this feature is done. So can I merge it?

[michaelmairegger]

@punker76 yes

[kamilkosek]

Thanks guys