How to set label background with opacity from windows8palette

[Lukasz]

I am trying to use AccentColor for label background with opacity:

<telerik:Label>
    <telerik:Label.Background>
        <SolidColorBrush Color="{telerik:Windows8Resource ResourceKey=AccentBrush}" Opacity="0.1"/>
    </telerik:Label.Background>
</telerik:Label>

This gives me an error: "#FF25A0DA" is not a valid value for property 'Color'.

How to get a valid color value in xaml?

[Martin]

Hi Lukasz,

The error is occurring because you are assigning a SolidColorBrush as a Color property of a SolidColorBrush. The brush resources of our themes (e.g. AccentBrush) are already SolidColorBrushes.

You can achieve the desired result by getting the color value of the AccentBrush ( I could guess it is #FF25A0DA ) and change its opacity. The structure of the ColorValue is [AA][RR][GG][BB], where AA is alpha. So you can redefine the Color as #1925A0DA (as 19 is 10% of FF).

Or in a similar way you are setting it now with Opacity as a separate property, only assign a color to the Color setter, not a SolidColorBrush reference.

<telerik:Label>
    <telerik:Label.Background>
        <SolidColorBrush Color="#FF25A0DA" Opacity="0.1"/>
    </telerik:Label.Background>
</telerik:Label>

Regards,
Martin
Telerik by Progress

[Lukasz]

Thanks for your reply. Can I somehow avoid using hardcoded value and get color value from resources? I am using Windows8 theme and I want my label to use color from theme and just add opacity to it.

Thanks,

Łukasz

[Martin]

Hello Lukasz,

You can add you the Window.Resources a custom brush, that you can define using the theme palette:

public MainWindow()
{
    Color win8Accent = Windows8Palette.Palette.AccentColor;
    byte opacity = (byte)((double)win8Accent.A * 0.5);
    Color MyColor = Color.FromArgb(opacity, win8Accent.R, win8Accent.G, win8Accent.B);
    var CustomBrush = new SolidColorBrush(MyColor);

    InitializeComponent();

    this.Resources.Add("CustomBrush", CustomBrush);
}

And refer it as a {DynamicResource CustomBrush}.

Regards,
Martin
Telerik by Progress