/// <inheritdoc /> public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { if (!this.initialized) { this.Initialize(); } var message = this.errorText.ToString(); if (!(targetType == typeof(Capacitance) || targetType == typeof(Capacitance?))) { message += $"{this.GetType().Name} does not support converting to {targetType.Name}"; } if (message != string.Empty) { message = message.TrimEnd('\r', '\n'); if (Is.DesignMode) { throw new InvalidOperationException(message); } return(message); } if (value == null) { return(null); } if (value is double) { return(new Capacitance((double)value, this.unit.Value)); } var text = value as string; if (string.IsNullOrEmpty(text)) { return(null); } var unitInput = this.UnitInput ?? Wpf.UnitInput.ScalarOnly; switch (unitInput) { case Wpf.UnitInput.ScalarOnly: { double d; if (double.TryParse(text, NumberStyles.Float, culture, out d)) { return(new Capacitance(d, this.unit.Value)); } Capacitance result; if (Capacitance.TryParse(text, NumberStyles.Float, culture, out result)) { return($"#{text}#"); // returning modified text so that TypeConverter fails and we get an error } return(text); // returning raw to trigger error } case Wpf.UnitInput.SymbolAllowed: { double d; int pos = 0; WhiteSpaceReader.TryRead(text, ref pos); if (DoubleReader.TryRead(text, ref pos, NumberStyles.Float, culture, out d)) { WhiteSpaceReader.TryRead(text, ref pos); if (pos == text.Length) { return(new Capacitance(d, this.unit.Value)); } } goto case Wpf.UnitInput.SymbolRequired; } case Wpf.UnitInput.SymbolRequired: { Capacitance result; if (Capacitance.TryParse(text, NumberStyles.Float, culture, out result)) { return(result); } return(text); } default: throw new ArgumentOutOfRangeException(); } }