private ExpressionObserver CreateDataContextSubject(
IObservablePropertyBag target,
string path,
bool targetIsDataContext)
{
Contract.Requires <ArgumentNullException>(target != null);
if (!targetIsDataContext)
{
var update = target.GetObservable(Control.DataContextProperty)
.Skip(1)
.Select(_ => Unit.Default);
var result = new ExpressionObserver(
() => target.GetValue(Control.DataContextProperty),
path,
update);
return(result);
}
else
{
return(new ExpressionObserver(
target.GetObservable(Visual.VisualParentProperty)
.OfType <IObservablePropertyBag>()
.Select(x => x.GetObservable(Control.DataContextProperty))
.Switch(),
path));
}
}
private ExpressionObserver CreateTemplatedParentExpressionSubject(IObservablePropertyBag target)
{
var result = new ExpressionObserver(
() => target.GetValue(Control.TemplatedParentProperty),
GetExpression());
if (target.GetValue(Control.TemplatedParentProperty) == null)
{
// TemplatedParent should only be set once, so only listen for the first non-null
// value.
target.GetObservable(Control.TemplatedParentProperty)
.Where(x => x != null)
.Take(1)
.Subscribe(x => result.UpdateRoot());
}
return(result);
}
private ExpressionObserver CreateTemplatedParentSubject(
IObservablePropertyBag target,
string path)
{
Contract.Requires <ArgumentNullException>(target != null);
var result = new ExpressionObserver(
() => target.GetValue(Control.TemplatedParentProperty),
path);
if (target.GetValue(Control.TemplatedParentProperty) == null)
{
// TemplatedParent should only be set once, so only listen for the first non-null
// value.
target.GetObservable(Control.TemplatedParentProperty)
.Where(x => x != null)
.Take(1)
.Subscribe(x => result.UpdateRoot());
}
return(result);
}
private ExpressionObserver CreateTemplatedParentSubject(
IObservablePropertyBag target,
string path)
{
Contract.Requires <ArgumentNullException>(target != null);
var update = target.GetObservable(Control.TemplatedParentProperty)
.Skip(1)
.Select(_ => Unit.Default);
var result = new ExpressionObserver(
() => target.GetValue(Control.TemplatedParentProperty),
path,
update);
return(result);
}
private ExpressionObserver CreateTemplatedParentSubject(
IObservablePropertyBag target,
string path)
{
Contract.Requires<ArgumentNullException>(target != null);
var result = new ExpressionObserver(
() => target.GetValue(Control.TemplatedParentProperty),
path);
if (target.GetValue(Control.TemplatedParentProperty) == null)
{
// TemplatedParent should only be set once, so only listen for the first non-null
// value.
target.GetObservable(Control.TemplatedParentProperty)
.Where(x => x != null)
.Take(1)
.Subscribe(x => result.UpdateRoot());
}
return result;
}
private ExpressionObserver CreateDataContextSubject(
IObservablePropertyBag target,
string path,
bool targetIsDataContext)
{
Contract.Requires<ArgumentNullException>(target != null);
if (!targetIsDataContext)
{
var result = new ExpressionObserver(
() => target.GetValue(Control.DataContextProperty),
path);
/// TODO: Instead of doing this, make the ExpressionObserver accept an "update"
/// observable as doing it this way can will cause a leak in Binding as this
/// observable is never unsubscribed.
target.GetObservable(Control.DataContextProperty).Subscribe(x =>
result.UpdateRoot());
return result;
}
else
{
return new ExpressionObserver(
target.GetObservable(Visual.VisualParentProperty)
.OfType<IObservablePropertyBag>()
.Select(x => x.GetObservable(Control.DataContextProperty))
.Switch(),
path);
}
}
private ExpressionObserver CreateTemplatedParentSubject(
IObservablePropertyBag target,
string path)
{
Contract.Requires<ArgumentNullException>(target != null);
var update = target.GetObservable(Control.TemplatedParentProperty)
.Skip(1)
.Select(_ => Unit.Default);
var result = new ExpressionObserver(
() => target.GetValue(Control.TemplatedParentProperty),
path,
update);
return result;
}
private ExpressionObserver CreateDataContextSubject(
IObservablePropertyBag target,
string path,
bool targetIsDataContext)
{
Contract.Requires<ArgumentNullException>(target != null);
if (!targetIsDataContext)
{
var update = target.GetObservable(Control.DataContextProperty)
.Skip(1)
.Select(_ => Unit.Default);
var result = new ExpressionObserver(
() => target.GetValue(Control.DataContextProperty),
path,
update);
return result;
}
else
{
return new ExpressionObserver(
target.GetObservable(Visual.VisualParentProperty)
.OfType<IObservablePropertyBag>()
.Select(x => x.GetObservable(Control.DataContextProperty))
.Switch(),
path);
}
}
private ExpressionObserver CreateTemplatedParentExpressionSubject(IObservablePropertyBag target)
{
var result = new ExpressionObserver(
() => target.GetValue(Control.TemplatedParentProperty),
GetExpression());
if (target.GetValue(Control.TemplatedParentProperty) == null)
{
// TemplatedParent should only be set once, so only listen for the first non-null
// value.
target.GetObservable(Control.TemplatedParentProperty)
.Where(x => x != null)
.Take(1)
.Subscribe(x => result.UpdateRoot());
}
return result;
}
