/// <summary>
/// Creates a new instance of the <see cref="Binding{T}"/> class.
/// </summary>
/// <param name="composition"></param>
/// <param name="componentTypeId"></param>
/// <param name="propertyBindings"></param>
public Binding(INuPatternCompositionService composition, string componentTypeId, params PropertyBinding[] propertyBindings)
{
Guard.NotNull(() => composition, composition);
Guard.NotNullOrEmpty(() => componentTypeId, componentTypeId);
this.componentTypeId = componentTypeId;
this.composition = composition;
this.propertyBindings = propertyBindings;
ResolveComponentTypeId();
composition.SatisfyImportsOnce(this);
}
/// <summary>
/// Evaluates this binding.
/// </summary>
/// <returns><see langword="true"/>, if the evaluation of the binding succeded; otherwise <see langword="false"/>.</returns>
public virtual bool Evaluate()
{
if (GuidanceManagerSettings.VerboseBindingTracing)
{
tracer.Verbose(Resources.Binding_TraceEvaluate,
this.lazyValue == null ? this.ToString() : this.lazyValue.Metadata.Id, this);
}
this.evaluationResults.Clear();
if (this.lazyValue == null)
{
// Re-evaluate component from MEF as new available exports
// might have made it available whereas previously it was not.
ResolveComponentTypeId();
}
bool evaluationResult;
if (this.Value == null)
{
evaluationResult = false;
var bindingResult = new BindingResult(@"this");
bindingResult.Errors.Add(string.Format(CultureInfo.CurrentCulture,
Resources.Binding_EvaluateBindingError,
this.componentTypeId, typeof(T).Name));
this.evaluationResults.Add(@"this", bindingResult);
}
else
{
var initializable = this.Value as ISupportInitialize;
var editable = this.Value as IEditableObject;
if (initializable != null)
{
initializable.BeginInit();
}
if (editable != null)
{
editable.BeginEdit();
}
composition.SatisfyImportsOnce(this.Value);
evaluationResult = this.EvaluateProperties();
if (evaluationResult)
{
evaluationResult = this.Validate();
if (evaluationResult)
{
if (editable != null)
{
editable.EndEdit();
}
if (initializable != null)
{
initializable.EndInit();
}
}
else
{
if (editable != null)
{
editable.CancelEdit();
}
}
}
else
{
// We don't call EndInit as we didn't end.
if (editable != null)
{
editable.CancelEdit();
}
}
}
this.HasErrors = !evaluationResult;
if (GuidanceManagerSettings.VerboseBindingTracing)
{
tracer.Verbose(ObjectDumper.ToString(this, 5));
}
return(evaluationResult);
}
