Load Images According To Dark And Light Theme in WP7

Question

In my current Windows Phone 7 app, we want to use two themes: Dark And Light, and we are also using some panoramic and pivot controls in our app. Each control has a different image for each dark and light theme.

For this purpose, I made two separate themes in my project. However, I am unable to load images for the theme. Can anyone please suggest how I can load images from the theme according to whether it is the dark or light version?

Answer 1

I Guess Better Approach is Make Two Separate Themes One For Light And Dark Theme And Then Take Decsion On Application Loading By Theme Visibility Bit.

In our Theme We Can Load Images Like That

<BitmapImage x:Key="SearchImage" UriSource="/Images/searchIcon.png" />

Answer 2

If you're only displaying images you can create a ValueConverter to determine the theme:

// Assumes a dark theme image is passed in the parameter variable 
public class ImageThemeValueConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if(parameter == null) return null;

        Visibility darkBackgroundVisibility = 
            (Visibility)Application.Current.Resources["PhoneDarkThemeVisibility"];

        if (darkBackgroundVisibility == Visibility.Visible)
        {
            return new Uri(parameter.ToString();
        }
        else
        {
            string path = parameter.ToString();
            path = System.IO.Path.GetDirectoryName(path) + System.IO.Path.GetFileNameWithoutExtension(path) + ".light"+System.IO.Path.GetExtension(path);
            return new Uri(path);
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

and in your xaml:

<Image Source="{Binding Converter={StaticResource ImageThemeValueConverter}, ConverterParameter=Images/ThemeImage.png}"/>

If putting the images in an button and the images only use the background and foreground colors (black and white) you can have a style that will change the color.

<Button Style="{StaticResource PhoneButton}">
    <ImageBrush ImageSource="/Images/appbar.save.png" Stretch="None"/>
</Button>

And the style:

<Style TargetType="Button" x:Key="PhoneButton">
    <Setter Property="Width" Value="48"/>
    <Setter Property="Height" Value="48"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <Grid>
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal"/>
                            <VisualState x:Name="MouseOver">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(FrameworkElement.HorizontalAlignment)" Storyboard.TargetName="ContentContainer">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <HorizontalAlignment>Stretch</HorizontalAlignment>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(FrameworkElement.VerticalAlignment)" Storyboard.TargetName="ContentContainer">
                                        <DiscreteObjectKeyFrame KeyTime="0">
                                            <DiscreteObjectKeyFrame.Value>
                                                <VerticalAlignment>Stretch</VerticalAlignment>
                                            </DiscreteObjectKeyFrame.Value>
                                        </DiscreteObjectKeyFrame>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Pressed">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ContentContainer">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneBackgroundBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="Border">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneForegroundBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Stroke" Storyboard.TargetName="Border">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneForegroundBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Disabled">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ContentContainer">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Stroke" Storyboard.TargetName="Border">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="Border">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="Transparent"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <Grid>
                        <Ellipse x:Name="Border" Fill="{TemplateBinding Background}" Canvas.Left="0" Stretch="Fill" 
                                    StrokeThickness="3" StrokeLineJoin="Round" Stroke="{TemplateBinding BorderBrush}"/>
                        <Grid x:Name="ContentContainer" OpacityMask="{TemplateBinding Content}" Background="{TemplateBinding Foreground}"/>
                    </Grid>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Answer 3

You can use the following code snippet to decide the theme, and set the images accordingly.

if ((double)Application.Current.Resources["PhoneDarkThemeOpacity"] == 1)
{
  //Dark Theme
}
else
{
  //Light Theme
}

You can also have a look here for more details.