How to change windows universal app default accent color? - xaml

Question

i want to change the accent color in my app (windows universal app) from the default one to a custom color that is defined in my app.
Any idea how can I do this?

Answer 1

You cannot really change the base Accent color in your application because that's defined by the system theme color (Taskbar, Startmenu, etc...). However, you can MODIFY the Accent color by using styles. Here's an example:
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App1">
<!-- Basic Colors -->
<SolidColorBrush x:Key="SystemAccentTransparentHighBrush" Color="{ThemeResource SystemAccentColor}" Opacity="0.9"/>
<SolidColorBrush x:Key="SystemAccentTransparentMediumHighBrush" Color="{ThemeResource SystemAccentColor}" Opacity="0.7" />
<SolidColorBrush x:Key="SystemAccentTransparentMediumBrush" Color="{ThemeResource SystemAccentColor}" Opacity="0.6" />
<SolidColorBrush x:Key="SystemAccentTransparentMediumLowBrush" Color="{ThemeResource SystemAccentColor}" Opacity="0.5" />
<SolidColorBrush x:Key="SystemAccentTransparentLowBrush" Color="{ThemeResource SystemAccentColor}" Opacity="0.3" />
<SolidColorBrush x:Key="SystemAccentHighlightBrush" Color="{ThemeResource SystemAccentColor}" />
<SolidColorBrush x:Key="SystemBlackBrush" Color="{ThemeResource SystemChromeBlackHighColor}" />
<SolidColorBrush x:Key="SystemWhiteBrush" Color="{ThemeResource SystemChromeWhiteColor}" />
<SolidColorBrush x:Key="SystemGreyHighBrush" Color="#FFE0E0E0" />
<SolidColorBrush x:Key="SystemGreyMediumHighBrush" Color="#FFA0A0A0" />
<SolidColorBrush x:Key="SystemGreyMediumBrush" Color="#FF808080" />
<SolidColorBrush x:Key="SystemGreyMediumLowBrush" Color="#FF606060" />
<SolidColorBrush x:Key="SystemGreyLowBrush" Color="#FF404040" />
<SolidColorBrush x:Key="SystemAppBackgroundBrush" Color="{ThemeResource ApplicationPageBackgroundThemeBrush}" />
<Style x:Key="GridStyle_Page" TargetType="Grid">
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="VerticalAlignment" Value="Top" />
<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled" />
<Setter Property="Background" Value="{StaticResource SystemBlackBrush}" />
</Style>
</ResourceDictionary>
You would put that in a styles.xaml file. Then you have to tell the system about it as follows in the App.xaml file:
<Application
x:Class="App1.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App1"
RequestedTheme="Light">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Styles.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>
Finally, you use the styles/colors in your application by doing one of the following:
Add a Style="{StaticResource }" to the element that you
want to style. You would replace with a style that is
defined in the Styles.xaml file above.
Add a color attribute such as Forground, Background, or Border to
the element that you want to color. To do this, add something like
Background="{StaticResource }" where the is
replaced by one of the color styles above.
To modify the accent color, you need to overlay it over a background color. Notice in the SolidColorBrush definitions above. Some of them have an Opacity setting. The range for this setting is between 1.0 and 0.0 where 1.0 is completely opaque while 0.0 is completely transparent. So the lower the Opacity setting, the more of the underlying color shows through. If the underlying color is black, then a lower Opacity setting will give you a darker Accent color. If the underlying color is white, then you will get a lighter Accent color as the Opacity value decreases.
A note about styles: Much of how xaml works is through styles. There are a couple of files on the computer that defines what all the styles are in the system. Those files are generic.xaml and themeresources.xaml. On my system (Windows 10 Pro RTM with VS2015), these files are found in the following location:
C:\Program Files (x86)\Windows Kits\10\DesignTime\CommonConfiguration\Neutral\UAP\10.0.10240.0\Generic
I hope this helps and sorry for the late answer. I just came across your question while I was googling for something else.

Answer 2

Have you tried using:
(App.Current.Resources["PhoneAccentBrush"] as SolidColorBrush).Color = Colors.Blue;
in you App.xaml.cs?