How to add : with label where text value is binding dynamically? - xaml

Question

How I can add : with string at my label in xaml in xamarin.forms. I have a text coming from app resource file by (i18n:Translate Text=Supplier). Now with this text I also add : after this text. I don't want to add : in app resource with text. I want to do that it on xaml only. I tried with StringFormat but don't know how I can do it.

Answer 1

You can use a Value Converter to change the value on your Binding, but it's tricky because you can't easily add a converter while using i18n:Translate. But I still see three possible solutions to your problem:
1. Property without Value Converter
The easiest way would be to create a Property which gets the translated text and then adds a colon to your text:
ViewModel:
public string Supplier
{
get { return AppResources.Supplier + ":"; }
}
XAML:
<Label Text="{Binding Supplier}"/>
2. Property with Value converter
Another way is to create a property which gets the translated text and then add the colon via a Value Converter:
ViewModel:
public string Supplier
{
get { return AppResources.Supplier; }
}
Converter class:
public class ColonConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return value += ":";
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return value.ToString().Remove(value.ToString().Length - 1);
}
}
XAML:
<ContentPage.Resources>
<ResourceDictionary>
<local:ColonConverter x:Key="ColonConverter" />
</ResourceDictionary>
</ContentPage.Resources>
...
<Label Text={Binding Supplier, Converter={StaticResource ColonConverter}}"/>
3. Create your own Translate Extension and Value Converter
I didn't test this, but I found this SO answer which gives an example on how to achieve that. This way you don't need to add properties to your ViewModel, so you only have to adjust your XAML once you set up the Translate Extension and Converter. But it's needs some work to write your own Translate Extension.
Custom TranslateExtension:
[ContentProperty("Text")]
public class TranslateExtension : IMarkupExtension
{
const string ResourceId = "Project.Resources.AppResources";
public string Text { get; set; }
public IValueConverter Converter { get; set; }
public object ProvideValue(IServiceProvider serviceProvider)
{
if (Text == null)
return null;
ResourceManager resourceManager = new ResourceManager(ResourceId, typeof(TranslateExtension).GetTypeInfo().Assembly);
string translatedText = resourceManager.GetString(Text, CultureInfo.CurrentCulture);
if (this.Converter != null)
{
translatedText = Converter.Convert(translatedText, typeof(string), null, CultureInfo.CurrentCulture).ToString() ?? translatedText;
}
return translatedText;
}
}
XAML:
xmlns:strings="clr-namespace:Project.Utils;assembly=Project"
<ContentPage.Resources>
<ResourceDictionary>
<converters:ColonSpaceConverter x:Key="ColonSpaceConverter" />
</ResourceDictionary>
</ContentPage.Resources>
<Label Text="{strings:Translate Money, Converter={StaticResource ColonSpaceConverter}}" />

Answer 2

This can be achieved in many ways, drafting two of them: (Value of Label will be changed on sliding the Slider)
Method 1
<Label Text="Slide to change Value"
VerticalOptions="CenterAndExpand"
HorizontalOptions="CenterAndExpand"
x:Name="lblSliderValue" FontSize="Title" Margin="60"></Label>
<Slider ValueChanged="Slider_ValueChanged"></Slider>
And in CodeBehind file,
private void Slider_ValueChanged(object sender, ValueChangedEventArgs e)
{
lblSliderValue.Text = e.NewValue.ToString("0.00");
lblSliderValue.BackgroundColor = Color.Black;
lblSliderValue.TextColor = Color.White;
}
Method 2 (No need of code in CodeBehind file)
<Label Text="Slide to change Value"
VerticalOptions="Center"
HorizontalOptions="Center"
Text="{Binding Source={x:Reference sldExample}, Path=Value, StringFormat='{0:F2}'}"></Label>
<Slider x:Name="sldExample" BackgroundColor="Yellow" ThumbColor="Violet"></Slider>