Quelques résultats de recherche pour OneWayToSource ...
Option 1.
public partial class FlagThingy : UserControl
{
public static readonly DependencyProperty IsModifiedProperty =
DependencyProperty.Register("IsModified", typeof(bool), typeof(FlagThingy), new PropertyMetadata());
}
<controls:FlagThingy x:Name="_flagThingy" />
Binding binding = new Binding();
binding.Path = new PropertyPath("FlagIsModified");
binding.ElementName = "container";
binding.Mode = BindingMode.OneWayToSource;
_flagThingy.SetBinding(FlagThingy.IsModifiedProperty, binding);
Option 2
public partial class FlagThingy : UserControl
{
public static readonly DependencyProperty IsModifiedProperty =
DependencyProperty.Register("IsModified", typeof(bool), typeof(FlagThingy), new PropertyMetadata());
public bool IsModified
{
get { return (bool)GetValue(IsModifiedProperty); }
set { throw new Exception("An attempt ot modify Read-Only property"); }
}
}
<controls:FlagThingy IsModified="{Binding Path=FlagIsModified,
ElementName=container, Mode=OneWayToSource}" />
Option 3 (vraie propriété de dépendance en lecture seule)
System.ArgumentException: la propriété 'IsModified' ne peut pas être liée aux données.
public partial class FlagThingy : UserControl
{
private static readonly DependencyPropertyKey IsModifiedKey =
DependencyProperty.RegisterReadOnly("IsModified", typeof(bool), typeof(FlagThingy), new PropertyMetadata());
public static readonly DependencyProperty IsModifiedProperty =
IsModifiedKey.DependencyProperty;
}
<controls:FlagThingy x:Name="_flagThingy" />
Same binding code...
Reflector donne la réponse:
internal static BindingExpression CreateBindingExpression(DependencyObject d, DependencyProperty dp, Binding binding, BindingExpressionBase parent)
{
FrameworkPropertyMetadata fwMetaData = dp.GetMetadata(d.DependencyObjectType) as FrameworkPropertyMetadata;
if (((fwMetaData != null) && !fwMetaData.IsDataBindingAllowed) || dp.ReadOnly)
{
throw new ArgumentException(System.Windows.SR.Get(System.Windows.SRID.PropertyNotBindable, new object[] { dp.Name }), "dp");
}
....