Override Specific Style Properties using Resource Dictionary - wpf

Question

I am trying to override the styles of Material Design for Xaml ToolKit as per my requirements, the following is the xaml in app.xaml which i came up with after reading about overriding on the github page of the library, but it seems to be not working and i am not getting why, as i have not much experience working in WPF applications, here is the code i tried:
<Color x:Key="DarkBlueColor">#00479D</Color>
<FontFamily x:Key="MicrosoftYaHei">Microsoft YaHei</FontFamily>
<SolidColorBrush x:Key="WindowBrush" Color="#00479D"/>
<Style x:Key="WindowStyle"
x:Name="WindowStyle"
BasedOn="{StaticResource MaterialDesignPaper}"
TargetType="{x:Type Window}">
<Setter Property="Background" Value="{DynamicResource WindowBrush}"></Setter>
</Style>
For the time being to get familiar i am only trying to change the background of the window, here is the code from MainWindow.xaml:
<Window x:Class="WPFApplication.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:XCMG.CarMan2"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525"
Style="{StaticResource WindowStyle}"
xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes">
<Grid>
</Grid>
</Window>
When i run the application after adding the above code, it throws an exception saying:
Unable to cast object of type 'System.Windows.Media.SolidColorBrush' to type 'System.Windows.Style'.

Answer 1

"MaterialDesignPaper" is a SolidColorBrush and you can't base a Window style on a Brush.
Remove the BasedOn attribute and the x:Name from your Style:
<Style x:Key="WindowStyle"
TargetType="{x:Type Window}">
<Setter Property="Background" Value="{DynamicResource WindowBrush}"></Setter>
</Style>
but i want override MaterialDesignBrush BackGround
Define a new Brush resource with the same key then:
<SolidColorBrush x:Key="MaterialDesignPaper" Color="#00479D"/>