Trying to get my Expander to resize with frame control - wpf

Question

I am creating a XAML page that loads inside of a Frame control. It included an Expander control. I need for the Expander and all contents of the Expander to resize horizontally as the user resized the window. Does anyone have any suggestions, please?
<Grid>
<StackPanel x:Name="Stackpanel1" HorizontalAlignment="Stretch" Margin="8,8,0,10" Orientation="Horizontal" VerticalAlignment="Stretch">
<Expander ExpandDirection="Right" IsExpanded="True" Expanded="Expander_Expanded">
<Expander.Header>
<TextBlock Text="Daily" RenderTransformOrigin=".5,.5">
<TextBlock.LayoutTransform>
<RotateTransform Angle="90" />
</TextBlock.LayoutTransform>
</TextBlock>
</Expander.Header>
<StackPanel Orientation="Vertical"
TextBlock.Foreground="{DynamicResource MaterialDesignBody}"
Margin="8,0,16,0" Height="610">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid Grid.Row="0" Grid.Column="0" Width="Auto">
<materialDesign:Card Grid.Column="1" Padding="5" UniformCornerRadius="8" Margin="0,5,0,0" >
<StackPanel Orientation="Horizontal"
TextBlock.Foreground="{DynamicResource MaterialDesignBody}"
Margin="8,24,16,24">
<TextBox x:Name="txtReprint" MinWidth="300"/>
<Button x:Name="btnReprint" Content="Re-Print" Margin="10,0,0,0" Width="156" Click="btnReprint_Click"/>
</StackPanel>
</materialDesign:Card>
</Grid>
<materialDesign:Card Grid.Column="0" Grid.Row="1" Padding="5" UniformCornerRadius="8" Margin="0,5,0,0" VerticalAlignment="Top" Height="508">
<StackPanel Orientation="Vertical"
TextBlock.Foreground="{DynamicResource MaterialDesignBody}"
Margin="8,0,16,0" VerticalAlignment="Top">
<Label x:Name="lblPriority" Content="Priority" VerticalAlignment="Top"/>
<DataGrid x:Name="dgvPriority" Width="467" Height="414"/>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button x:Name="btnPriorityRefresh" Content="Refresh" Grid.Column="0" Margin="5,10,5,0" Click="btnPriorityRefresh_Click"/>
<Button x:Name="btnPriorityPrint" Content="Print" Grid.Column="1" Margin="5,10,5,0" Click="btnPriorityPrint_Click"/>
</Grid>
</StackPanel>
</materialDesign:Card>
<materialDesign:Card Grid.Column="1" Grid.Row="1" Padding="5" UniformCornerRadius="8" Margin="5,5,0,0" VerticalAlignment="Top" Height="508">
<StackPanel Orientation="Vertical"
TextBlock.Foreground="{DynamicResource MaterialDesignBody}"
Margin="8,0,16,0" VerticalAlignment="Top">
<Label x:Name="lblGround" Content="Ground" VerticalAlignment="Top"/>
<DataGrid x:Name="dgvPGround" Width="467" Height="414" HorizontalAlignment="Stretch"/>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button x:Name="btnGroundRefresh" Content="Refresh" Grid.Column="0" Margin="5,10,5,0" Click="btnGroundRefresh_Click"/>
<Button x:Name="btnGroundPrint" Content="Print" Grid.Column="1" Margin="5,10,5,0" Click="btnGroundPrint_Click"/>
</Grid>
</StackPanel>
</materialDesign:Card>
</Grid>
</StackPanel>
</Expander>
<Border Background="{DynamicResource MaterialDesignDivider}" Width="1" VerticalAlignment="Stretch" SnapsToDevicePixels="True" />
<Expander ExpandDirection="Right" Expanded="Expander_Expanded">
<Expander.Header>
<TextBlock Text="Special Projects" RenderTransformOrigin=".5,.5">
<TextBlock.LayoutTransform>
<RotateTransform Angle="90" />
</TextBlock.LayoutTransform>
</TextBlock>
</Expander.Header>
<materialDesign:Card Grid.Column="1" Grid.Row="1" Padding="5" UniformCornerRadius="8" Margin="5,5,5,5" VerticalAlignment="Top" Height="603">
<StackPanel Orientation="Vertical"
TextBlock.Foreground="{DynamicResource MaterialDesignBody}"
Margin="8,24,16,3">
<Label x:Name="lblSpecialProjects" Content="Special Projects"/>
<DataGrid x:Name="dgvNAB" Width="467" Height="477" Margin="0,5,0,0"/>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button x:Name="btnNABRefresh" Content="Refresh" Grid.Column="0" Margin="5,10,5,0" Click="btnNABRefresh_Click"/>
<Button x:Name="btnNABPrint" Content="Print" Grid.Column="1" Margin="5,10,5,0" Click="btnNABPrint_Click"/>
</Grid>
</StackPanel>
</materialDesign:Card>
</Expander>
</StackPanel>
</Grid>

Answer 1

Instead of a StackPanel you could use a Grid and create columns. Each Expander you put in a separate column and that way you can make them adjust according to the window size.