Hi, I want to define the background for my application in App.XAML. The background was previously defined in another xaml page,which have multiple Grids inside it like following:

<Grid x:Key="GridGeneric" d:LayoutOverrides="Width, Height">
        <Grid.Background>
            <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                <GradientStop Color="#FF00172E" Offset="1"/>
                <GradientStop Color="#FF004074" Offset="0.433"/>
                <GradientStop Color="#FF081316"/>
                <GradientStop Color="#FF001D3F" Offset="0.215"/>
                <GradientStop Color="#FF002043" Offset="0.818"/>
                <GradientStop Color="#FF003B6C" Offset="0.642"/>
            </LinearGradientBrush>
        </Grid.Background>
        <Grid>
            <Grid.Background>
                <RadialGradientBrush RadiusY="0.973" GradientOrigin="0.497,-0.276" RadiusX="1.003">
                    <GradientStop Color="#FFB350EE" Offset="0"/>
                    <GradientStop Color="#001D3037" Offset="0.847"/>
                </RadialGradientBrush>
            </Grid.Background>
        </Grid>

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</Grid>

Now I want to place the same in my App.xaml like following:

<Style x:Key="backgroundStyle" TargetType="Grid">

        <Setter Property="Background">
            <Setter.Value>
                <Grid>
                    <Grid.Background>
                        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                            <GradientStop Color="#FF00172E" Offset="1"/>
                            <GradientStop Color="#FF004074" Offset="0.433"/>
                            <GradientStop Color="#FF081316"/>
                            <GradientStop Color="#FF001D3F" Offset="0.215"/>
                            <GradientStop Color="#FF002043" Offset="0.818"/>
                            <GradientStop Color="#FF003B6C" Offset="0.642"/>
                        </LinearGradientBrush>
                    </Grid.Background>
           <Grid>
             <Grid.Background>
                <RadialGradientBrush RadiusY="0.973" GradientOrigin="0.497,-0.276" RadiusX="1.003">
                        <GradientStop Color="#FFB350EE" Offset="0"/>
                        <GradientStop Color="#001D3037" Offset="0.847"/>
                    </RadialGradientBrush>
                </Grid.Background>
            </Grid>
                         ---------
                         ---------
                </Grid>
            </Setter.Value>
        </Setter>

    </Style>

But While doing this I am getting the following Exception.