Translation of dynamic data

[susloparovdenis]

I can't figure out how to use binding with echoes:Translate markup extension.
I have an enum prop in my ViewModel with statuses like:
Pending
Done
InWork
And I need to translate them in view. How would I do that?
Thanks

[JaggerJo]

You can use a converter like this, but converters can only return values so if the language changes your translations will be stuck. I'm working on a solution for this - but it's a more complicated issue related to bindings in Avalonia.

public enum Mood
{
    Good,
    Bad
}

public static class Converters
{
    // The issue is here, converters cannot themselves return for example an IObservable<string> that emits new translations when the language changes.
    public static FuncValueConverter<Mood, string>  MoodConverter 
        => new (mood => mood switch
        {
            Mood.Good => Strings.mood_good.CurrentValue,
            Mood.Bad => Strings.mood_bad.CurrentValue,
        });
}

public class ViewModel 
{
    public Mood Mood
    {
        get => _mood;
        set => SetField(ref _mood, value);
    }
    
    public ImmutableList<Mood> MoodOptions => [ Mood.Good, Mood.Bad ];
}

<TextBlock 
    Text="{Binding Mood, Converter={x:Static sampleApp:Converters.MoodConverter}}"/>
<ComboBox 
    ItemsSource="{Binding MoodOptions}"
    SelectedValue="{Binding Mood}">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding ., Converter={x:Static sampleApp:Converters.MoodConverter}}"/>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

[E021ntox]

@JaggerJo Dynamic translation not working on NativeMenuItem https://docs.avaloniaui.net/docs/reference/controls/tray-icon#example

[JaggerJo]

@E021ntox does binding to Observables for NativeMenuItems?

Should be simple to verify, just bind to an IObservable using the hat (^) stream binding operator. Probably is an issue in Avalonia itself.

Native* controls are special. On what OS are you?

[E021ntox]

@E021ntox does binding to Observables for NativeMenuItems?

Should be simple to verify, just bind to an IObservable using the hat (^) stream binding operator. Probably is an issue in Avalonia itself.

Native* controls are special. On what OS are you?

Windows. Just <NativeMenuItem Command="{Binding xxx}" Header="{echoes:Translate {x:Static translations:Strings.xxx}}" />

[JaggerJo]

@E021ntox does binding to Observables for NativeMenuItems?
Should be simple to verify, just bind to an IObservable using the hat (^) stream binding operator. Probably is an issue in Avalonia itself.
Native* controls are special. On what OS are you?

Windows. Just <NativeMenuItem Command="{Binding xxx}" Header="{echoes:Translate {x:Static translations:Strings.xxx}}" />

Would be interesting if the code below works.

You'd need an IObservable<string> Header in your view model to test it.

<NativeMenuItem Command="{Binding xxx}" Header="{Binding Header^}" />

[E021ntox]

You'd need an IObservable<string> Header in your view model to test it.
<NativeMenuItem Command="{Binding xxx}" Header="{Binding Header^}" />

It works, thanks. But there is a new bug. The menu accelerator is broken.
https://docs.avaloniaui.net/docs/reference/controls/menu#accelerator-keys

[E021ntox]

@JaggerJo How to use string formater in xaml?
https://github.com/Voyonic-Systems/Echoes/blob/main/README.md?plain=1#L103

[JaggerJo]

Write a converter

[E021ntox]

Write a converter

Thanks, could you provide some sample code? Or add it to the NuGet package?

[MarkusKgit]

You can do something like this:

Create an extension in your project:

using Avalonia;
using Avalonia.Data;
using Avalonia.Data.Converters;
using Avalonia.Markup.Xaml;
using Echoes;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;

namespace YourNameSpace.Markup;

public class TranslateWithParametersExtension : MarkupExtension
{
    private readonly TranslationUnit _unit;
    public object[] Args { get; }

    public TranslateWithParametersExtension(TranslationUnit unit, object arg1)
    {
        _unit = unit;
        Args = [arg1];
    }

    public TranslateWithParametersExtension(TranslationUnit unit, object arg1, object arg2)
    {
        _unit = unit;
        Args = [arg1, arg2];
    }
        
    public TranslateWithParametersExtension(TranslationUnit unit, object arg1, object arg2, object arg3)
    {
        _unit = unit;
        Args = [arg1, arg2, arg3];
    }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        var formatBinding = (IBinding)_unit.Value.ToBinding();

        if (Args.Length == 0)
            return formatBinding;

        var multi = new MultiBinding
        {
            Converter = new FormatConverter()
        };
        multi.Bindings.Add(formatBinding);
                
        foreach (var arg in Args)
        {
            if (arg is IBinding b)
                multi.Bindings.Add(b);
            else
                multi.Bindings.Add(new Binding { Source = arg });
        }

        return multi;
    }
    private sealed class FormatConverter : IMultiValueConverter
    {
        public object Convert(IList<object?> values, Type t, object? p, CultureInfo c)
        {
            if (values == null || values.Count == 0)
                return string.Empty;

            var formatStr = values[0]?.ToString() ?? string.Empty;
            var args = values.Skip(1).ToArray();

            try
            {
                return string.Format(c, formatStr, args);
            }
            catch
            {
                return formatStr;
            }
        }
    }
}

Just add constructors with more parameters if you need more than 3

In Xaml you can now use it like so:

xmlns:local="clr-namespace:YourNameSpace.Markup"
...
<TextBox Text="{Binding Name}"/>
<TextBlock Text="{local:TranslateWithParameters {x:Static translations:Strings.greeting}, {Binding Name}, '123', '456'}"/>

assuming the following string as an example: greeting = "Hello {0}! {1} {2}"

[E021ntox]

You can do something like this:

Create an extension in your project:

Thank you so much! Maybe we could refine it and integrate it into Echoes, so everyone can benefit from it.