Question

I am using WPF databinding. I can format the number if I specify StringFormat={}{0:C}. However, if I use StringFormat={}{0:X2}, it will give give the following exception:

System.Windows.Data Error: 6 : 'StringFormat' converter failed to convert value '10' (type 'Double'); fallback value will be used, if available. BindingExpression:Path=Value; DataItem='Slider' (Name='SliderG'); target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String') FormatException:'System.FormatException: Format specifier was invalid.
   at System.Number.FormatDouble(Double value, String format, NumberFormatInfo info)
   at System.Double.ToString(String format, IFormatProvider provider)
   at System.Text.StringBuilder.AppendFormat(IFormatProvider provider, String format, Object[] args)
   at System.String.Format(IFormatProvider provider, String format, Object[] args)
   at System.Windows.Data.BindingExpression.ConvertHelper(IValueConverter converter, Object value, Type targetType, Object parameter, CultureInfo culture)'
'WpfApplication1.vshost.exe' (Managed (v4.0.30319)): Loaded 'C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Numerics\v4.0_4.0.0.0__b77a5c561934e089\System.Numerics.dll', Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.

Anyone gets any idea?

Answer 1

The hexadecimal format specifier only works with integer types. You’re trying to apply it to a floting point (double) value. You’ll need to convert your bound value to an integer type (int, long, etc) if you want to format it as a hexadecimal value.