CODEWITHSUNDEEP
c#wpfxamluser-controls
avechuche
avechuche

Reputation: 1560

Binding issue in custom user control

I created a usercontrol but I can not make the binding work, I tried in many ways but I did not get it to work, the value is not displayed.

ShowPrice.cs

public static readonly DependencyProperty ValueProperty =
            DependencyProperty.Register("Value", typeof(string), typeof(ShowPrice),
                new FrameworkPropertyMetadata
                (
                    string.Empty,
                    FrameworkPropertyMetadataOptions.Journal |
                    FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
                    OnValuePropertyChanged
                ));

    public string Value
    {
        get { return (string)GetValue(ValueProperty); }
        set { SetValue(ValueProperty, value); }
    }

    private static void OnValuePropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
    {
        var showPrice = obj as ShowPrice;
        showPrice?.SetValue(ValueProperty, (string)e.NewValue);
    }

ShowPrice.xaml

<UserControl x:Class="WPF.CustomControls.UserControls.ShowPrice"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         DataContext="{Binding RelativeSource={RelativeSource Self}}">

        <TextBlock Text="{Binding Value}"
                   HorizontalAlignment="Center"
                   Foreground="White"
                   FontSize="40"
                   Margin="5" />

</UserControl>

My view.xaml

<userControls:ShowPrice Value="{Binding MyViewModelProperty, StringFormat=C2, ConverterCulture='es-AR'}">
</userControls:ShowPrice>

If I write a value if it works

<userControls:ShowPrice Value="Test"/>

Upvotes: 0

Views: 46

Answers (1)

15ee8f99-57ff-4f92-890c-b56153
15ee8f99-57ff-4f92-890c-b56153

Reputation: 37059

Don't bind DataContext to Self. Use a RelativeSource binding instead (but this isn't the problem):

Text="{Binding Value, RelativeSource={RelativeSource AncestorType=UserControl}}"

Also, get rid of your OnValuePropertyChanged handler. It's called when Value is set, so it's hardly necessary to set Value again (but that's not the problem either).

Finally, this may be your problem:

Foreground="White"

Is this thing being used on a white background? I kept all of your code exactly as you had it, and made one change:

<TextBlock 
    Text="{Binding Value}"
    Background="YellowGreen"
    HorizontalAlignment="Center"
    Foreground="White"
    FontSize="40"
    Margin="5" 
    />

This:

    Background="YellowGreen"

And I saw white text on a yellow-green background.

Upvotes: 1

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