/// <summary>
/// RaiseAndSetIfChanged fully implements a Setter for a read-write
/// property on a ReactiveObject, making the assumption that the
/// property has a backing field named "_NameOfProperty". To change this
/// assumption, set RxApp.GetFieldNameForPropertyNameFunc.
/// </summary>
/// <param name="property">An Expression representing the property (i.e.
/// 'x => x.SomeProperty'</param>
/// <param name="newValue">The new value to set the property to, almost
/// always the 'value' keyword.</param>
/// <returns>The newly set value, normally discarded.</returns>
public static TRet RaiseAndSetIfChanged <TObj, TRet>(
this TObj This,
Expression <Func <TObj, TRet> > property,
TRet newValue)
where TObj : ReactiveObject
{
Contract.Requires(This != null);
Contract.Requires(property != null);
FieldInfo field;
string prop_name = RxApp.simpleExpressionToPropertyName <TObj, TRet>(property);
field = RxApp.getFieldInfoForProperty <TObj>(prop_name);
var field_val = field.GetValue(This);
if (EqualityComparer <TRet> .Default.Equals((TRet)field_val, (TRet)newValue))
{
return(newValue);
}
This.raisePropertyChanging(prop_name);
field.SetValue(This, newValue);
This.raisePropertyChanged(prop_name);
return(newValue);
}
/// <summary>
/// Converts an Observable to an ObservableAsPropertyHelper and
/// automatically provides the onChanged method to raise the property
/// changed notification.
/// </summary>
/// <param name="source">The ReactiveObject that has the property</param>
/// <param name="property">An Expression representing the property (i.e.
/// 'x => x.SomeProperty'</param>
/// <param name="initialValue">The initial value of the property.</param>
/// <param name="scheduler">The scheduler that the notifications will be
/// provided on - this should normally be a Dispatcher-based scheduler
/// (and is by default)</param>
/// <returns>An initialized ObservableAsPropertyHelper; use this as the
/// backing field for your property.</returns>
public static ObservableAsPropertyHelper <TRet> ToProperty <TObj, TRet>(
this IObservable <TRet> This,
TObj source,
Expression <Func <TObj, TRet> > property,
TRet initialValue = default(TRet),
IScheduler scheduler = null)
where TObj : ReactiveObject
{
var ret = source.ObservableToProperty(This, property, initialValue, scheduler);
string propName = RxApp.simpleExpressionToPropertyName(property);
var fi = RxApp.getFieldInfoForProperty <TObj>(propName);
fi.SetValue(source, ret);
return(ret);
}
/// <summary>
/// Converts an Observable to an ObservableAsPropertyHelper and
/// automatically provides the onChanged method to raise the property
/// changed notification.
/// </summary>
/// <param name="source">The ReactiveObject that has the property</param>
/// <param name="property">An Expression representing the property (i.e.
/// 'x => x.SomeProperty'</param>
/// <param name="initialValue">The initial value of the property.</param>
/// <param name="scheduler">The scheduler that the notifications will be
/// provided on - this should normally be a Dispatcher-based scheduler
/// (and is by default)</param>
/// <returns>An initialized ObservableAsPropertyHelper; use this as the
/// backing field for your property.</returns>
public static ObservableAsPropertyHelper <TRet> ToProperty <TObj, TRet>(
this IObservable <TRet> This,
TObj source,
Expression <Func <TObj, TRet> > property,
TRet initialValue = default(TRet),
IScheduler scheduler = null)
where TObj : ReactiveObject
{
var ret = source.ObservableToProperty(This, property, initialValue, scheduler);
string propName = RxApp.simpleExpressionToPropertyName(property);
// NB: Some people decided to name their backing field something
// weird and use the return value of this method in RxUI 2. If they
// did that, we'll just roll with it.
var fi = RxApp.getFieldInfoForProperty <TObj>(propName, true);
if (fi != null)
{
fi.SetValue(source, ret);
}
return(ret);
}