public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
if (compiledExpression == null)
{
if ((compiledExpression = CompileExpression(null, (string)parameter, true, new List<Type>{targetType})) == null)
return null;
}
if (compiledInversedExpression == null)
{
//try convert back expression
try
{
var resType = compiledExpression.Expression.Type;
var param = Expression.Parameter(resType, "Path");
compiledInversedExpression = new Inverter(parser).InverseExpression(compiledExpression.Expression, param);
}
catch (Exception e)
{
Trace.WriteLine("Binding error: calc converter can't convert back expression " + parameter + ": " + e.Message);
}
}
if (compiledInversedExpression != null)
{
try
{
if (targetType == typeof(bool) && value.GetType() == typeof(Visibility))
value = new BoolToVisibilityConverter(FalseToVisibility)
.ConvertBack(value, targetType, null, culture);
if (value is string && compiledExpression.Expression.Type != value.GetType())
value = ParseStringToObject((string)value, compiledExpression.Expression.Type);
var source = compiledInversedExpression.Invoke(value);
return source;
}
catch (Exception e)
{
Trace.WriteLine("Binding error: calc converter can't invoke back expression " + parameter + ": " + e.Message);
}
}
return null;
}
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (values == null)
return null;
if (sourceValuesTypes == null)
{
sourceValuesTypes = GetTypes(values);
}
else
{
var currentValuesTypes = GetTypes(values);
if (!sourceValuesTypes.SequenceEqual(currentValuesTypes))
{
sourceValuesTypes = currentValuesTypes;
compiledExpression = null;
compiledInversedExpression = null;
}
}
if (compiledExpression == null)
{
if ((compiledExpression = CompileExpression(values, (string)parameter)) == null)
return null;
}
try
{
var result = compiledExpression.Invoke(values);
if (!StringFormatDefined)
{
if (targetType == typeof(Visibility))
{
result = new BoolToVisibilityConverter(FalseToVisibility)
.Convert(result, targetType, null, culture);
}
if (targetType == typeof(String))
result = String.Format(CultureInfo.InvariantCulture, "{0}", result);
}
return result;
}
catch (Exception e)
{
Trace.WriteLine("Binding error: calc converter can't invoke expression " + compiledExpression.ExpressionText + ": " + e.Message);
return null;
}
}