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The ColorToColorForTextConverter is a one way converter that allows users to convert an incoming Color to a monochrome value of either Colors.Black or Colors.White based on whether it is determined as being dark for the human eye.
The Convert method returns the supplied value converted to either Colors.Black or Colors.White based on whether the supplied value is considered dark for the human eye or not.
The ConvertBack method is not supported.
BaseConverter Properties
The following properties are implemented in the base class, public abstract class BaseConverter:
| Property | Description |
|---|---|
DefaultConvertReturnValue |
Default value to return when IValueConverter.Convert(object?, Type, object?, CultureInfo?) throws an Exception. This value is used when CommunityToolkit.Maui.Options.ShouldSuppressExceptionsInConverters is set to true. |
DefaultConvertBackReturnValue |
Default value to return when IValueConverter.ConvertBack(object?, Type, object?, CultureInfo?) throws an Exception. This value is used when CommunityToolkit.Maui.Options.ShouldSuppressExceptionsInConverters is set to true. |
ICommunityToolkitValueConverter Properties
The following properties are implemented in the public interface ICommunityToolkitValueConverter:
| Property | Type | Description |
|---|---|---|
DefaultConvertReturnValue |
object? |
Default value to return when IValueConverter.Convert(object?, Type, object?, CultureInfo?) throws an Exception. This value is used when CommunityToolkit.Maui.Options.ShouldSuppressExceptionsInConverters is set to true. |
DefaultConvertBackReturnValue |
object? |
Default value to return when IValueConverter.ConvertBack(object?, Type, object?, CultureInfo?) throws an Exception. This value is used when CommunityToolkit.Maui.Options.ShouldSuppressExceptionsInConverters is set to true. |
Syntax
XAML
Including the XAML namespace
In order to use the toolkit in XAML the following xmlns needs to be added into your page or view:
xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
Therefore the following:
<ContentPage
x:Class="CommunityToolkit.Maui.Sample.Pages.MyPage"
xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml">
</ContentPage>
Would be modified to include the xmlns as follows:
<ContentPage
x:Class="CommunityToolkit.Maui.Sample.Pages.MyPage"
xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit">
</ContentPage>
Using the ColorToColorForTextConverter
The ColorToColorForTextConverter can be used as follows in XAML:
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
x:Class="CommunityToolkit.Maui.Sample.Pages.Converters.ColorToColorForTextConverterPage">
<ContentPage.Resources>
<ResourceDictionary>
<toolkit:ColorToColorForTextConverter x:Key="ColorToColorForTextConverter" />
</ResourceDictionary>
</ContentPage.Resources>
<Label Text="The Text is showing in an optimum color against the background"
TextColor="{Binding Source={RelativeSource AncestorType={x:Type ContentPage}}, Path=BackgroundColor, Converter={StaticResource ColorToColorForTextConverter}}" />
</ContentPage>
C#
The ColorToColorForTextConverter can be used as follows in C#:
class ColorToColorForTextConverterPage : ContentPage
{
public ColorToColorForTextConverterPage()
{
var label = new Label { Text = "The Text is showing in an optimum color against the background" };
label.SetBinding(
Label.TextColorProperty,
new Binding(
static (ContentPage page) => page.BackgroundColor,
converter: new ColorToColorForTextConverter(),
source: this));
Content = label;
}
}
C# Markup
Our CommunityToolkit.Maui.Markup package provides a much more concise way to use this converter in C#.
using CommunityToolkit.Maui.Markup;
class ColorToColorForTextConverterPage : ContentPage
{
public ColorToColorForTextConverterPage()
{
Content = new Label { Text = "The Text is showing in an optimum color against the background" }
.Bind(
Label.TextColorProperty,
static (ContentPage page) => page.BackgroundColor,
converter: new ColorToColorForTextConverter(),
source: this);
}
}
Examples
You can find an example of this converter in action in the .NET MAUI Community Toolkit Sample Application.
API
You can find the source code for ColorToColorForTextConverter over on the .NET MAUI Community Toolkit GitHub repository.
.NET MAUI Community Toolkit