public object ConvertBack(object value, Type targetType)
{
if (targetType == null)
{
throw new ArgumentNullException(nameof(targetType));
}
var valueConverter = ValueConverterProvider.Get <TValueConverter>();
var convertedValue = BindingValue.UnsetValue;
if (TryGetParameter(out var parameter))
{
try
{
convertedValue = valueConverter.ConvertBack(value, targetType, parameter, _converterCulture);
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while converting \"{value ?? "null"}\" value from the target item to the source one " +
$"using \"{TypeFormatter.FormatName<TValueConverter>()}\" value converter.");
}
}
return(convertedValue);
}
protected void SetTargetItemValue([NotNull] TTargetItem targetItem, [CanBeNull] object targetItemValue)
{
if (targetItemValue == BindingValue.UnsetValue)
{
if (FallbackValue != null)
{
targetItemValue = FallbackValue.Value;
}
else
{
if (!SourceItemBinding.TryGetItem(out _))
{
Log("Source item is null and fallback value is not set. " +
"This may lead to diplaying value from the previous source item. " +
"Set fallback value to override previous one.");
}
}
}
if (targetItemValue != BindingValue.UnsetValue)
{
try
{
TargetItemBinding.SetValue(targetItem, (TTargetItemValue)targetItemValue, _compositeItemBindingMode == BindingMode.TwoWay);
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while executing " +
$"\"{LogFormatter.FormatTypeName(TargetItemBinding)}.{nameof(TargetItemBinding.SetValue)}\" method.");
}
}
}
internal SourceItemEmptyBinding(
[NotNull] ItemReference <TItem> itemReference,
[NotNull] Type sourceItemBindingType,
[CanBeNull] LambdaExpression itemValue,
[NotNull] Exception ex)
: base(itemReference, () => LogFormatter.FormatExpression(itemValue))
{
Log($"\"{LogFormatter.FormatException(ex)}\" exception occurred while creating " +
$"\"{LogFormatter.FormatTypeName(sourceItemBindingType)}\" instance.");
}
protected bool TryGetTargetItemValue([NotNull] TTargetItem targetItem, out TTargetItemValue targetItemValue)
{
try
{
return(TargetItemBinding.TryGetValue(targetItem, out targetItemValue));
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while executing " +
$"\"{LogFormatter.FormatTypeName(TargetItemBinding)}.{nameof(TargetItemBinding.TryGetValue)}\" method.");
targetItemValue = default;
return(false);
}
}
protected bool TryGetSourceItemValue([NotNull] TSourceItem sourceItem, out TSourceItemValue sourceItemValue)
{
try
{
return(SourceItemBinding.TryGetValue(sourceItem, out sourceItemValue));
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while executing " +
$"\"{LogFormatter.FormatTypeName(SourceItemBinding)}.{nameof(SourceItemBinding.TryGetValue)}\" method.");
sourceItemValue = default;
return(false);
}
}
protected override void UnsubscribeFromSourceItemEvents()
{
if (SourceItemBinding.TryGetItem(out var sourceItem))
{
try
{
SourceItemBinding.UnsubscribeFromEvents(sourceItem);
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while executing " +
$"\"{LogFormatter.FormatTypeName(SourceItemBinding)}.{nameof(SourceItemBinding.UnsubscribeFromEvents)}\" method.");
}
SourceItemBinding.CanExecuteChanged -= SourceItemCommandBinding_CanExecuteChanged;
}
}
internal object ConvertBack([CanBeNull] object value, [NotNull] Type targetType, [CanBeNull] object parameter)
{
var valueConverter = ValueConverterFactory.GetOrCreate(_converterType);
try
{
return(valueConverter.ConvertBack(value, targetType, parameter, _converterCulture));
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while converting \"{value ?? "null"}\" value from the target item to the source one " +
$"using \"{LogFormatter.FormatTypeName(_converterType)}\" value converter. This might reduce binding performance. " +
$"Please return \"{nameof(BindingValue)}.{nameof(BindingValue.UnsetValue)}\" value instead of rising an exception.");
return(BindingValue.UnsetValue);
}
}
protected void SetSourceItemValue([NotNull] TSourceItem sourceItem, [CanBeNull] TTargetItemValue targetItemValue)
{
var sourceItemValue = ValueConverter.ConvertBack(targetItemValue, typeof(TSourceItemValue));
if (sourceItemValue != BindingValue.UnsetValue)
{
try
{
SourceItemBinding.SetValue(sourceItem, (TSourceItemValue)sourceItemValue, _compositeItemBindingMode == BindingMode.TwoWay);
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while executing " +
$"\"{LogFormatter.FormatTypeName(SourceItemBinding)}.{nameof(SourceItemBinding.SetValue)}\" method.");
}
}
}
private void UnsubscribeFromTargetItemEvents()
{
if (TargetItemBinding.TryGetItem(out var targetItem))
{
if (IsFromTargetToSourceBindingMode())
{
try
{
TargetItemBinding.UnsubscribeFromEvents(targetItem);
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while executing " +
$"\"{LogFormatter.FormatTypeName(TargetItemBinding)}.{nameof(TargetItemBinding.UnsubscribeFromEvents)}\" method.");
}
}
}
}
protected override void UnsubscribeFromSourceItemEvents()
{
if (SourceItemBinding.TryGetItem(out var sourceItem))
{
if (IsFromSourceToTargetBindingMode(includingOneTimeBindingMode: false))
{
try
{
SourceItemBinding.UnsubscribeFromEvents(sourceItem);
}
catch (Exception ex)
{
Log($"An \"{LogFormatter.FormatException(ex)}\" exception occurred while executing " +
$"\"{LogFormatter.FormatTypeName(SourceItemBinding)}.{nameof(SourceItemBinding.UnsubscribeFromEvents)}\" method.");
}
}
}
}