/// <summary>
/// Tries to cast a value to a type, taking into account that the value may be a
/// <see cref="BindingError"/>.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="type">The type.</param>
/// <returns>The cast value, or a <see cref="BindingError"/>.</returns>
private static object CastOrDefault(object value, Type type)
{
var error = value as BindingError;
if (error == null)
{
return(TypeUtilities.CastOrDefault(value, type));
}
else
{
return(error);
}
}
/// <summary>
/// Binds a <see cref="PerspexProperty"/> to an observable.
/// </summary>
/// <param name="property">The property.</param>
/// <param name="source">The observable.</param>
/// <param name="priority">The priority of the binding.</param>
/// <returns>
/// A disposable which can be used to terminate the binding.
/// </returns>
public IDisposable Bind(
PerspexProperty property,
IObservable <object> source,
BindingPriority priority = BindingPriority.LocalValue)
{
Contract.Requires <ArgumentNullException>(property != null);
VerifyAccess();
if (property.IsDirect)
{
property = GetRegistered(property);
if (property.Setter == null)
{
throw new ArgumentException($"The property {property.Name} is readonly.");
}
_propertyLog.Verbose(
"Bound {Property} to {Binding} with priority LocalValue",
property,
GetDescription(source));
return(source
.Select(x => TypeUtilities.CastOrDefault(x, property.PropertyType))
.Subscribe(x => SetValue(property, x)));
}
else
{
PriorityValue v;
if (!PerspexPropertyRegistry.Instance.IsRegistered(this, property))
{
ThrowNotRegistered(property);
}
if (!_values.TryGetValue(property, out v))
{
v = CreatePriorityValue(property);
_values.Add(property, v);
}
_propertyLog.Verbose(
"Bound {Property} to {Binding} with priority {Priority}",
property,
GetDescription(source),
priority);
return(v.Add(source, (int)priority));
}
}
/// <summary>
/// Tries to cast a value to a type, taking into account that the value may be a
/// <see cref="BindingNotification"/>.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="type">The type.</param>
/// <returns>The cast value, or a <see cref="BindingNotification"/>.</returns>
private static object CastOrDefault(object value, Type type)
{
var notification = value as BindingNotification;
if (notification == null)
{
return(TypeUtilities.CastOrDefault(value, type));
}
else
{
if (notification.HasValue)
{
notification.SetValue(TypeUtilities.CastOrDefault(notification.Value, type));
}
return(notification);
}
}