Use “real” CultureInfo.CurrentCulture in WPF Binding, not CultureInfo from IetfLanguageTag

Question

In my case:

I have a TextBlock Binding to a property of type DateTime. I want it to be displayed as the Regional settings of the User says.

Answer 1

I came up with a hack/workaround that avoids updating all your bindings. Add this code to the constructor of your main window.

XmlLanguage language = XmlLanguage.GetLanguage("My-Language");
typeof(XmlLanguage).GetField("_compatibleCulture", BindingFlags.Instance | BindingFlags.NonPublic).SetValue(language, CultureInfo.CurrentCulture);
this.Language = language;

Since it's using reflection there is no guarantee that it will work in the future, but for now it does (.NET 4.6).

Answer 2

This is an extension of answer from aKzenT. They proposed that we should create a subclass of Binding class and set the ConverterCulture to CurrentCulture. Even though the answer is very straight forward, I feel some people may not be very comfortable implementing it, so I am sharing the code version of aKzenT's answer with an example of how to use it in XAML.

using System;
using System.Globalization;
using System.Windows.Data;

namespace MyWpfLibrary
{
    public class CultureAwareBinding : Binding
    {
        public CultureAwareBinding()
        {
            ConverterCulture = CultureInfo.CurrentCulture;
        }
    }
}

Example of how to use this in XAML

1) You need to import your namespace into your XAML file:

<Page
    ...
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:myWpfLib="clr-namespace:MyWpfLibrary;assembly=<assembly_name>"
    ...
>

2) Real world usage of the CultureAwareBinding

<Textblock Text="{myWpfLib:CultureAwareBinding Path=Salary, Source=Contact, StringFormat={}{0:C}}" />

Answer 3

I use that code with proper results to my needs. Hope it could fills your :-) ! Perhaps you are better throwing an exception if cannot "TryParse". Up to you.

public sealed class CurrentCultureDoubleConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return ((double)value).ToString((string)parameter ?? "0.######", CultureInfo.CurrentCulture);
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        double result;
        if (Double.TryParse(value as string, NumberStyles.Number, CultureInfo.CurrentCulture, out result))
        {
            return result;
        }

        throw new FormatException("Unable to convert value:" + value);
        // return value;
    }
}

Usage:

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:simulatorUi="clr-namespace:SimulatorUi"
        xmlns:Converter="clr-namespace:HQ.Wpf.Util.Converter;assembly=WpfUtil" x:Class="SimulatorUi.DlgTest"
        Title="DlgTest" Height="300" Width="300">
    <Window.DataContext>
        <simulatorUi:DlgTestModel/>
    </Window.DataContext>

    <Window.Resources>
        <Converter:CurrentCultureDoubleConverter x:Key="CurrentCultureDoubleConverter"/>
    </Window.Resources>

    <Grid>
        <TextBox Text="{Binding DoubleVal, Converter={StaticResource CurrentCultureDoubleConverter}}"/>
    </Grid>
</Window>