public static void Bind(XamlControl frameworkElement, string eventName, string methodPath, params object[] arguments)
{
var eventInfo = frameworkElement.GetType().GetEvent(eventName) ?? throw new MissingFieldException($"Cannot find \"{eventName}\" event");
var binding = new EventBinding(methodPath, arguments);
var handler = binding.Bind(frameworkElement, eventInfo);
eventInfo.AddEventHandler(frameworkElement, handler);
}
public Emitter(TypeBuilder typeBuilder, EventBinding eventBinding, XamlControl source)
{
_typeBuilder = typeBuilder;
_eventBinding = eventBinding;
_source = source;
_instanceField = _typeBuilder.DefineField("_instance", source.GetType(), FieldAttributes.Private);
_argumentsField = _typeBuilder.DefineField("_arguments", typeof(object[]), FieldAttributes.Private);
_timerField = _typeBuilder.DefineField("_timer", typeof(Timer), FieldAttributes.Private);
}
internal static object ResolveBinding(XamlBinding binding, XamlControl source, int position)
{
#if AVALONIA
var instancedBinding = binding.Initiate(source, _properties[position]);
BindingOperations.Apply(source, _properties[position], instancedBinding, null);
#else
if (!System.Windows.Data.BindingOperations.IsDataBound(source, _properties[position]))
{
System.Windows.Data.BindingOperations.SetBinding(source, _properties[position], binding);
}
#endif
return(source.GetValue(_properties[position]));
}
private EventInfo TryDetermineEventInfo(IServiceProvider serviceProvider, XamlControl frameworkElement)
{
var xamlContextField = serviceProvider.GetType().GetField("_xamlContext", BindingFlags.Instance | BindingFlags.NonPublic);
if (xamlContextField != null)
{
var xamlContext = xamlContextField.GetValue(serviceProvider);
var parentPropertyProp = xamlContext.GetType().GetProperty("ParentProperty");
var parentProperty = parentPropertyProp?.GetValue(xamlContext, null);
var nameProp = parentProperty?.GetType().GetProperty("Name");
if (nameProp != null)
{
var name = nameProp.GetValue(parentProperty, null).ToString();
return(frameworkElement.GetType().GetEvent(name));
}
}
return(null);
}
private Delegate Bind(XamlControl frameworkElement, EventInfo eventInfo)
{
var parameters = eventInfo.EventHandlerType.GetMethod("Invoke").GetParameters();
var parameterTypes = new Type[parameters.Length];
for (var i = 0; i < parameters.Length; i++)
{
parameterTypes[i] = parameters[i].ParameterType;
}
var handler = GenerateHandler(frameworkElement, eventInfo);
var sync = new object();
var binded = false;
frameworkElement.DataContextChanged += (sender, e) =>
{
lock (sync)
{
eventInfo.RemoveEventHandler(frameworkElement, handler);
handler = GenerateHandler(frameworkElement, eventInfo);
eventInfo.AddEventHandler(frameworkElement, handler);
binded = true;
}
};
#if AVALONIA
frameworkElement.DetachedFromVisualTree += (sender, e) =>
{
lock (sync)
{
eventInfo.RemoveEventHandler(frameworkElement, handler);
binded = false;
}
};
frameworkElement.AttachedToVisualTree += (sender, e) =>
{
lock (sync)
{
eventInfo.AddEventHandler(frameworkElement, handler);
binded = true;
}
};
#else
frameworkElement.Unloaded += (sender, e) =>
{
lock (sync)
{
eventInfo.RemoveEventHandler(frameworkElement, handler);
binded = false;
}
};
frameworkElement.Loaded += (sender, e) =>
{
lock (sync)
{
if (!binded)
{
eventInfo.AddEventHandler(frameworkElement, handler);
binded = true;
}
}
};
#endif
return(handler);
}
private Delegate GenerateHandler(XamlControl frameworkElement, EventInfo eventInfo)
{
return(frameworkElement.DataContext != null
? _eventHandlerGenerator.GenerateHandler(eventInfo.EventHandlerType, this, frameworkElement)
: _eventHandlerGenerator.GenerateEmptyHandler(eventInfo.EventHandlerType));
}
