AppThemeBinding with StaticResource in Codebehind

Question

Hi,

How can I set the below TextColor in Codebehind?

TextColor="{AppThemeBinding Light={StaticResource FontIconLight}, Dark={StaticResource FontIconDark}}"  

Thanks,
Jassim

Answer 1

Hello,

How can I set the below TextColor in Codebehind?

You can use SetAppThemeColor to set the text color in the code behind.

For example, I have button and need to set the text color in the code behind.

• Method 1: If you put your FontIconLight Color in the current page's <ContentPage.Resources>.

  <ContentPage.Resources\>  
  <Color x:Key="FontIconLight"\>red\</Color\>  
  <Color x:Key="LightSecondaryColor"\>Black\</Color\>  
  <Color x:Key="FontIconDark"\>Teal\</Color\>  
  <Color x:Key="DarkSecondaryColor"\>White\</Color\>  
  </ContentPage.Resources\>

You can use this.Resources get the color with following code.

   MyButton.SetAppThemeColor(Button.TextColorProperty, this.Resources["FontIconLight"] as Color, this.Resources["FontIconDark"] as Color);  

• Method 2: If you put your FontIconLight Color in the Resources/Styles/Colors.xaml, you need to create a custom static dictionary to access merged dictionaries in App.xaml.cs like following code.

  public App()  
  {  
  InitializeComponent();  
  MainPage = new AppShell()  
  ResourceDictionary = new Dictionary\<string, ResourceDictionary\>();  
  foreach (var dictionary in Application.Current.Resources.MergedDictionaries)  
  {  
  string key = dictionary.Source.OriginalString.Split(';').First().Split('/').Last().Split('.').First();  
  ResourceDictionary.Add(key, dictionary);  
  }  
  }  
  public static Dictionary\<string, ResourceDictionary\> ResourceDictionary;

Then you can use App.ResourceDictionary get the color with following code.

   MyButton.SetAppThemeColor(Button.TextColorProperty, (Color)App.ResourceDictionary["Colors"]["FontIconLight"], (Color)App.ResourceDictionary["Colors"]["FontIconDark"]);  

Best Regards,

Leon Lu

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Answer 2

I want to provide a slightly better solution than the previous answer; however, I couldn't have done it without their answer first.

1. Go to App.xaml file and set up your resource dictionaries.
2. Go to App.cs and add a public static ResourceDictionary MyColors.
3. Simple search for the name of the file with a linq query and save it to the static variable.
4. You can now access it from anywhere with your code with App.MyColors["key"].

App.xaml

<Application.Resources>
	<ResourceDictionary>
    	<ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Resources/Styles/Colors.xaml" />
            <ResourceDictionary Source="Resources/Styles/Styles.xaml" />
 
            <ResourceDictionary Source="Resources/Styles/MyColors.xaml" />
        	<ResourceDictionary Source="Resources/Styles/MyStyles.xaml" />
    	</ResourceDictionary.MergedDictionaries>
	</ResourceDictionary>
</Application.Resources>

App.cs

#pragma warning disable CS8618
public static ResourceDictionary MyColors = new();
#pragma warning restore CS8618
 
public App()
{
	InitializeComponent();
	MyColors = Resources.MergedDictionaries
		.Where(x => x.Source.ToString().Contains("MyColors"))
		.First();
		 
	MainPage = new AppShell();
}

Wherever in your application

Button.BackgroundColor = App.MyColors["Primary"];