This is my XAML
To gain access to the Resource of the code must identify them in the file App.xaml:
XAML example
The Resource can be changed in code line of the form:
Application.Current.Resources["MyResource"] = MyNewValue;
Example:
Code behind
// using ContentRendered event
private void Window_ContentRendered(object sender, EventArgs e)
{
SolidColorBrush MyBrush = Brushes.Aquamarine;
// Set the value
Application.Current.Resources["DynamicBG"] = MyBrush;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
SolidColorBrush MyBrush = Brushes.CadetBlue;
// Set the value
Application.Current.Resources["DynamicBG"] = MyBrush;
}
Principle, DynamicResources were designed, so they can be changed. Where to change - it is the task of the developer. In the case of Color, it is one of the most common methods. See the MSDN, for more information.
P. S. I recommend using App.xaml, because there have been cases where a StaticResource has been used successfully, but not DynamicResource (resources are placed in the Window.Resources). But after moving the resource in App.xaml, everything started to work.