/// <summary>
/// Event listener that is being invoked in one-way and two-way binding
/// scenarios whenever the source node value is being changed.
/// </summary>
private void OnSourceChanged(object?sender, DependencyChangeEventArgs <TSource> e)
{
//if we don't have a valid chain, skip immediately
if (TargetDependency.RootNode.IsChainBroken)
{
return;
}
TTarget targetValue;
if (e.ChangedNode.IsChainBroken)
{
targetValue = DefaultValue;
}
else
{
var sourceValue = e.TryGetLeafValue();
if (ForwardConverter != null)
{
targetValue = ForwardConverter(sourceValue !);
}
else
{
targetValue = (TTarget)(sourceValue as object);
}
}
//assign to target
var parent = TargetDependency.LeafNode.ParentNode?.NodeValue;
if (TargetMember != null)
{
SetMemberValue(TargetMember, parent, targetValue);
}
}
/// <summary>
/// Event listener that is being invoked in two-way binding scenarios whenever
/// the target node value is being changed.
/// </summary>
private void OnTargetChanged(object?sender, DependencyChangeEventArgs <TTarget> e)
{
//if the target is broken or the source is not accessible, do not update the source
if (SourceDependency.RootNode.IsChainBroken || TargetDependency.RootNode.IsChainBroken)
{
return;
}
var targetValue = e.TryGetLeafValue();
TSource sourceValue;
if (ReverseConverter != null)
{
sourceValue = ReverseConverter(targetValue !);
}
else
{
sourceValue = (TSource)(targetValue as object);
}
//only update the source if its value is different than the
//current one - re-assiging the same value produces a recursive
//update
if (sourceValue?.Equals(SourceDependency.LeafValue) == true)
{
return;
}
//assign to source
var parent = SourceDependency.LeafNode.ParentNode?.NodeValue;
if (SourceMember != null)
{
SetMemberValue(SourceMember, parent, sourceValue);
}
}
