WPF change dynamicresource in codebehind

Question

The standard RadioButton does not support setting the color of the ellipse. So, I took a radiobutton template from this location as a basis for a custom RadioButton: RadioButton Styles and Templates

<Ellipse.Fill>
<LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
    <LinearGradientBrush.GradientStops>
        <GradientStopCollection>
            <GradientStop Color="{DynamicResource ControlLightColor}" />
            <GradientStop Color="{DynamicResource ControlMediumColor}" Offset="1.0" />
        </GradientStopCollection>
    </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

ControlLightColor and ControlMediumColor are defined as:

<Color x:Key="ControlLightColor">#ffff9a</Color>
<Color x:Key="ControlMediumColor">#ffff9a</Color>

Which gives us a yellow-ish ellipse.

How can I alter this color in the codebehind?

Regards,

Michel

score 0 · Answer 1 · edited May 23 '17 at 11:49

0

Create a style by following this: Creating a Style in code behind

then assign it to your element.Style

You can also access resources by

Resources["mykey"]

edited May 23 '17 at 11:49

Community

1
1

answered May 24 '12 at 09:41

jrb

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I updated the Application.Current.Resources("ControlLightColor") with a different color, nothing happens. I also did a RaisePropertyChanged on my binding element, also doesn't work. – Michel van Engelen May 24 '12 at 10:17
maybe you have to call InitializeComponent(); It's probably better to crate two styles and just switch style. Or bind the gradientstop color to a property (MVVM) – jrb May 24 '12 at 11:14
Right hmm, then the only thin I can think about is creating new styles.. What is it that you are trying to accomplish btw? Maybe its easier to do in xaml – jrb May 24 '12 at 12:38
I have a stackpanel with an itemscontrol that displays multiple radiobuttons. The radiobuttons have a color to indicate that one of them must be chosen. when a radiobutton is clicked, all radiobuttons must change to a different color indicating that the mandatory question has been answered. Without doing some templatework, it's not possible to give a radiobutton a color. I was thinking about controltemplate triggers, but all of the rb's have to get the new color, not just the one clicked. – Michel van Engelen May 24 '12 at 12:49
Hmm this looks promising: binding to ellipse – Michel van Engelen May 24 '12 at 13:02

score 0 · Accepted Answer · edited Apr 30 '19 at 07:05

Solution:

<Ellipse x:Name="Border" StrokeThickness="1" Fill="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.RadioButtonColor}">

        Public ReadOnly Property RadioButtonColor() As SolidColorBrush
        Get
            Dim solidColorBrush As SolidColorBrush

            If MyBusinessLogic Then
                solidColorBrush = _radioButtonNotRequiredBrush
            Else
                solidColorBrush = _radioButtonRequiredBrush
            End If

            Return solidColorBrush
        End Get
    End Property

Thumbs up for JRB for thinking along.

WPF change dynamicresource in codebehind

2 Answers2