public static Action BindTarget(PropertyBinding propertyBinding, object dataContext)
{
AssertArg.IsNotNull(propertyBinding.View, "propertyBinding.View");
var view = propertyBinding.View as INotifyPropertyChanged;
if (view == null)
{
throw new InvalidOperationException("Binding target does not implement INotifyPropertyChanged.");
}
string propertyName = propertyBinding.TargetProperty.Name;
PropertyChangedEventHandler handler = (sender, args) =>
{
if (args.PropertyName == propertyName)
{
var rawValue = propertyBinding.TargetProperty.GetValue(propertyBinding.View);
ViewValueChangedHandler.HandleTargetValueChanged(propertyBinding, rawValue, dataContext);
}
};
view.PropertyChanged += handler;
Action removeAction = () => { view.PropertyChanged -= handler; };
return(removeAction);
}
public Action BindView(PropertyBinding propertyBinding, object dataContext)
{
EventHandler <TArgs> handler =
(sender, args) =>
{
ViewValueChangedHandler.HandleViewValueChanged(propertyBinding, newValueFunc, dataContext, args);
};
addHandler((TView)propertyBinding.View, handler);
Action removeAction = () => { removeHandler((TView)propertyBinding.View, handler); };
return(removeAction);
}
void Bind(BindingExpression bindingExpression,
object dataContext,
object originalDataContext,
string[] sourcePath,
IValueConverter converter,
PropertyInfo targetProperty,
IList <Action> localRemoveActions,
IList <Action> globalRemoveActions,
int position)
{
int pathSplitLength = sourcePath.Length;
/* If the path is empty we assign the data context to the target property
* or call the target method (if applicable). */
if (pathSplitLength < 1 || pathSplitLength == 1 && sourcePath[0] == ".")
{
if (targetProperty == null)
{
/* If the Source property of the data context
* is not a property, check if it's a method. */
var viewType = bindingExpression.View.GetType();
MethodInfo targetMethod = null;
Type dataContextType = dataContext.GetType();
try
{
#if NETSTANDARD
targetMethod = viewType.GetRuntimeMethod(bindingExpression.Target, new[] { dataContextType });
#else
targetMethod = viewType.GetMethod(bindingExpression.Target, new[] { dataContextType });
#endif
}
catch (Exception)
{
/* Ignore. */
}
if (targetMethod == null)
{
#if NETSTANDARD
targetMethod = viewType.GetRuntimeMethods().FirstOrDefault(
x => x.Name == bindingExpression.Target && x.IsPublic);
#else
targetMethod = viewType.GetMethod(bindingExpression.Target,
BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
#endif
}
if (targetMethod == null)
{
throw new InvalidOperationException($"Target property {bindingExpression.Target} does not exist "
+ $"on {bindingExpression.View?.GetType().Name}.");
}
CallTargetMethod(targetMethod, dataContext, bindingExpression.View, converter, bindingExpression.ConverterParameter);
}
else
{
SetTargetProperty(targetProperty, dataContext, bindingExpression.View, converter, bindingExpression.ConverterParameter);
}
return;
}
object currentContext = dataContext;
int lastIndex = pathSplitLength - 1;
PropertyBinding[] propertyBinding = new PropertyBinding[1];
for (int i = position; i < pathSplitLength; i++)
{
if (currentContext == null)
{
break;
}
var inpc = currentContext as INotifyPropertyChanged;
string sourceSegment = sourcePath[i];
#if NETSTANDARD
var sourceProperty = currentContext.GetType().GetRuntimeProperty(sourceSegment);
#else
var sourceProperty = currentContext.GetType().GetProperty(sourceSegment,
BindingFlags.Instance
| BindingFlags.NonPublic
| BindingFlags.Public);
#endif
if (i == lastIndex) /* The value. */
{
/* Add a property binding between the source (the viewmodel)
* and the target (the view) so we can update the target property
* when the source property changes (a OneWay binding). */
propertyBinding[0] = new PropertyBinding
{
SourceProperty = sourceProperty,
TargetProperty = targetProperty,
Converter = converter,
ConverterParameter = bindingExpression.ConverterParameter,
View = bindingExpression.View
};
{
/* When this value changes, the value must be pushed to the target.
* (Unless it's OneWayToSource or OneTime) */
var mode = bindingExpression.Mode;
if (sourceProperty != null && inpc != null && (mode != BindingMode.OneTime && mode != BindingMode.OneWayToSource))
{
object context = currentContext;
void HandlePropertyChanged(object sender, PropertyChangedEventArgs args)
{
string propertyName = args.PropertyName;
if (propertyName != sourceSegment && !string.IsNullOrEmpty(propertyName))
{
return;
}
PropertyBinding binding = propertyBinding[0];
if (binding != null && sourceProperty != null)
{
if (binding.PreventUpdateForTargetProperty)
{
return;
}
try
{
binding.PreventUpdateForSourceProperty = true;
if (binding.TargetMethod == null)
{
SetTargetProperty(sourceProperty, context, binding.View, binding.TargetProperty, binding.Converter, binding.ConverterParameter);
}
else
{
CallTargetMethod(binding.TargetMethod, sourceProperty, context, binding.View, binding.Converter, binding.ConverterParameter);
}
}
finally
{
binding.PreventUpdateForSourceProperty = false;
}
}
}
inpc.PropertyChanged += HandlePropertyChanged;
void RemoveHandler()
{
inpc.PropertyChanged -= HandlePropertyChanged;
propertyBinding[0] = null;
}
localRemoveActions.Add(RemoveHandler);
globalRemoveActions.Add(RemoveHandler);
}
}
/* Determine if the target is an event,
* in which case use that to trigger an update. */
#if NETSTANDARD
string targetName = bindingExpression.Target;
if (string.IsNullOrEmpty(targetName))
{
throw new BindingException($"Target is null or empty. Source: {bindingExpression.Source}, Path: {bindingExpression.Path}, View: {bindingExpression.View}");
}
var bindingEvent = bindingExpression.View.GetType().GetRuntimeEvent(bindingExpression.Target);
#else
var bindingEvent = bindingExpression.View.GetType().GetEvent(bindingExpression.Target);
#endif
if (bindingEvent != null)
{
/* The target is an event of the view. */
if (sourceProperty != null)
{
Func <object, object> getter = ReflectionCache.GetPropertyGetter(
sourceProperty,
DelegateCreationMode.FastCreationSlowPerformance);
/* The source must be an ICommand so we can call its Execute method. */
var command = getter(currentContext) as ICommand;
if (command == null)
{
throw new InvalidOperationException(
$"The source property {bindingExpression.Path}, "
+ $"bound to the event {bindingEvent.Name}, "
+ "needs to implement the interface ICommand.");
}
/* Subscribe to the specified event to execute
* the command when the event is raised. */
var invoker = ReflectionCache.GetVoidMethodInvoker(
commandExecuteMethodInfo,
DelegateCreationMode.FastCreationSlowPerformance);
void InvokeAction()
{
invoker(command, new object[] { null });
}
Action removeAction = DelegateUtility.AddHandler(bindingExpression.View, bindingExpression.Target, (Action)InvokeAction);
localRemoveActions.Add(removeAction);
globalRemoveActions.Add(removeAction);
/* Subscribe to the CanExecuteChanged event of the command
* to disable or enable the view associated to the command. */
var view = bindingExpression.View;
#if NETSTANDARD
PropertyInfo enabledProperty = view.GetType().GetRuntimeProperty(viewEnabledPropertyName);
#else
PropertyInfo enabledProperty = view.GetType().GetProperty(viewEnabledPropertyName);
#endif
if (enabledProperty != null)
{
var setter = ReflectionCache.GetPropertySetter(
enabledProperty,
DelegateCreationMode.FastCreationSlowPerformance);
setter(view, command.CanExecute(null));
Action canExecuteChangedAction = () => setter(view, command.CanExecute(null));
removeAction = DelegateUtility.AddHandler(
command, nameof(ICommand.CanExecuteChanged), canExecuteChangedAction);
localRemoveActions.Add(removeAction);
globalRemoveActions.Add(removeAction);
}
}
else /* sourceProperty == null */
{
/* If the Source property of the data context
* is not a property, check if it's a method. */
var contextType = currentContext.GetType();
#if NETSTANDARD
var sourceMethod = contextType.GetRuntimeMethods().FirstOrDefault(x => x.Name == sourceSegment);
#else
var sourceMethod = contextType.GetMethod(sourceSegment,
BindingFlags.Public | BindingFlags.NonPublic
| BindingFlags.Instance | BindingFlags.Static);
#endif
if (sourceMethod == null)
{
throw new InvalidOperationException(
$"No property or event named {bindingExpression.Path} "
+ $"on object of type {contextType} "
+ $"found to bind it to the event {bindingEvent.Name}.");
}
var parameterCount = sourceMethod.GetParameters().Length;
if (parameterCount > 3)
{
/* Only calls to methods with 0, 1, 2 or three parameters are supported. */
throw new InvalidOperationException(
$"Method {sourceMethod.Name} should accept three or fewer parameters "
+ $"to be called when event {bindingEvent.Name} is raised. The signature should resemble one of the following:" + Environment.NewLine
+ $"void MethodName() {Environment.NewLine}"
+ $"void MethodName(object dataContext, EventArgs e) {Environment.NewLine}"
+ "void MethodName(object dataContext, EventArgs e, object sender)");
}
/* It's a method therefore subscribe to the specified event
* to execute the method when the event is raised. */
var context = currentContext;
Action removeAction;
Action <object, object[]> invoker = ReflectionCache.GetVoidMethodInvoker(
sourceMethod,
DelegateCreationMode.FastCreationSlowPerformance);
if (parameterCount > 1)
{
removeAction = DelegateUtility.AddHandler(bindingExpression.View,
bindingExpression.Target,
(sender, e) =>
{
var args = parameterCount > 2 ? new[] { originalDataContext, e, bindingExpression.View } : new[] { originalDataContext, e };
invoker(context, args);
});
}
else
{
removeAction = DelegateUtility.AddHandler(bindingExpression.View,
bindingExpression.Target,
() =>
{
var args = parameterCount > 0 ? new[] { originalDataContext } : null;
invoker(context, args);
});
}
localRemoveActions.Add(removeAction);
globalRemoveActions.Add(removeAction);
}
}
else /* bindingEvent == null */
{
if (sourceProperty == null)
{
throw new InvalidOperationException(
$"Source property {bindingExpression.Path} does not exist "
+ $"on {currentContext?.GetType().Name ?? "null"}.");
}
MethodInfo targetMethod = null;
if (targetProperty == null)
{
/* If the Source property of the data context
* is not a property, check if it's a method. */
var viewType = bindingExpression.View.GetType();
try
{
#if NETSTANDARD
targetMethod = viewType.GetRuntimeMethod(bindingExpression.Target, new[] { sourceProperty.PropertyType });
#else
targetMethod = viewType.GetMethod(bindingExpression.Target, new[] { sourceProperty.PropertyType });
#endif
}
catch (Exception)
{
/* Ignore. */
}
if (targetMethod == null)
{
#if NETSTANDARD
targetMethod = viewType.GetRuntimeMethods().FirstOrDefault(x => x.Name == bindingExpression.Target && x.IsPublic);
#else
targetMethod = viewType.GetMethod(bindingExpression.Target,
BindingFlags.Public | BindingFlags.NonPublic
| BindingFlags.Instance | BindingFlags.Static);
#endif
}
if (targetMethod == null)
{
throw new InvalidOperationException(
$"Target property {bindingExpression.Target} does not exist "
+ $"on {bindingExpression.View?.GetType().Name}.");
}
propertyBinding[0].TargetMethod = targetMethod;
}
var mode = bindingExpression.Mode;
if (mode != BindingMode.OneWayToSource)
{
propertyBinding[0].PreventUpdateForSourceProperty = true;
try
{
object closureContext = currentContext;
UIContext.Instance.Send(() =>
{
/* Set initial binding value. */
if (targetMethod == null)
{
SetTargetProperty(sourceProperty, closureContext,
bindingExpression.View, targetProperty, converter,
bindingExpression.ConverterParameter);
}
else
{
CallTargetMethod(targetMethod, sourceProperty,
closureContext, bindingExpression.View,
converter, bindingExpression.ConverterParameter);
}
});
}
finally
{
propertyBinding[0].PreventUpdateForSourceProperty = false;
}
}
if (mode == BindingMode.TwoWay || mode == BindingMode.OneWayToSource)
{
/* TwoWay bindings require that the ViewModel property be updated
* when an event is raised on the bound view. */
string changedEvent = bindingExpression.ViewValueChangedEvent;
if (!string.IsNullOrWhiteSpace(changedEvent))
{
var context = currentContext;
Action changeAction = () =>
{
var pb = propertyBinding[0];
if (pb == null)
{
return;
}
ViewValueChangedHandler.HandleViewValueChanged(pb, context);
};
var view = bindingExpression.View;
var removeHandler = DelegateUtility.AddHandler(view, changedEvent, changeAction);
localRemoveActions.Add(removeHandler);
globalRemoveActions.Add(removeHandler);
}
else
{
var binding = propertyBinding[0];
IViewBinder binder;
if (ViewBinderRegistry.TryGetViewBinder(
binding.View.GetType(), binding.TargetProperty.Name, out binder))
{
var unbindAction = binder.BindView(binding, currentContext);
if (unbindAction != null)
{
localRemoveActions.Add(unbindAction);
globalRemoveActions.Add(unbindAction);
}
}
else
{
var viewInpc = binding.View as INotifyPropertyChanged;
if (viewInpc != null)
{
var unbindAction = InpcTargetBinder.BindTarget(binding, currentContext);
if (unbindAction != null)
{
localRemoveActions.Add(unbindAction);
globalRemoveActions.Add(unbindAction);
}
}
else if (Debugger.IsAttached)
{
var log = Dependency.Resolve <ILog>();
log.Debug($"Unable to locate value changed event for two way binding with target {bindingExpression.Target} "
+ $"on {bindingExpression.View?.GetType().Name}. Target does not implement INotifyPropertyChanged.");
Debugger.Break();
}
}
}
}
}
}
else
{
/* The source is a child of another object,
* therefore we must subscribe to the parents PropertyChanged event
* and re-bind when the child changes. */
if (inpc != null && bindingExpression.Mode != BindingMode.OneTime)
{
var context = currentContext;
var iCopy = i;
PropertyChangedEventHandler handler
= delegate(object sender, PropertyChangedEventArgs args)
{
string propertyName = args.PropertyName;
if (propertyName != sourceSegment && !string.IsNullOrEmpty(propertyName))
{
return;
}
/* Remove existing child event subscribers. */
var lastActionIndex = localRemoveActions.Count - 1;
var removeActions = new List <Action>();
for (int j = position; j < lastActionIndex; j++)
{
var removeAction = localRemoveActions[j];
try
{
removeAction();
}
catch (Exception)
{
var log = Dependency.Resolve <ILog>();
if (log.IsLogEnabledForLevel(LogLevel.Debug))
{
log.Debug("Binding failed. PropertyName: " + propertyName);
}
}
removeActions.Add(removeAction);
}
foreach (var removeAction in removeActions)
{
localRemoveActions.Remove(removeAction);
globalRemoveActions.Remove(removeAction);
}
propertyBinding[0] = null;
/* Bind child bindings. */
Bind(bindingExpression,
context,
originalDataContext,
sourcePath,
converter,
targetProperty,
localRemoveActions, globalRemoveActions, iCopy);
};
inpc.PropertyChanged += handler;
Action removeHandler = () =>
{
inpc.PropertyChanged -= handler;
propertyBinding[0] = null;
};
localRemoveActions.Add(removeHandler);
globalRemoveActions.Add(removeHandler);
}
if (sourceProperty != null)
{
var getter = ReflectionCache.GetPropertyGetter(
sourceProperty,
DelegateCreationMode.FastCreationSlowPerformance);
currentContext = getter(currentContext);
}
else
{
currentContext = null;
}
}
}
}
