WPF Have controls fill entire row

I am trying to get 2 buttons to be beside each other and evenly take up the entire row underneath the "main area".

I seem to be missing something

Thanks!

 <Grid Background="Transparent" Margin="0" Opacity=".8">

    <Border Name="MaskBorder" Grid.RowSpan="3">
        <Border Name="MainBorder" Background="Aqua">
            <Grid>

                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="30"/>
                    <ColumnDefinition Width="811*"/>
            开发者_如何学编程        <ColumnDefinition Width="30"/>
                </Grid.ColumnDefinitions>

                <!--Body-->
                <Grid Grid.ColumnSpan="4">
                    <Border Name="BodyBackground" Background="White" />
                </Grid>

                <!-- Main Area for Content -->
                <Grid Name="ContentGrid" Grid.Column="1">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="55" />
                        <RowDefinition Height="811*" />
                        <RowDefinition Height="30" />
                    </Grid.RowDefinitions>

                    <DockPanel LastChildFill="True" Grid.Row="1">

                        <Grid DockPanel.Dock="Bottom">
                            <Button Height="55"></Button>
                            <Button Height="55"></Button>
                        </Grid>

                        <Border Background="Black" />

                    </DockPanel>

                </Grid>

            </Grid>
        </Border>
    </Border>
</Grid>

---

You have the buttons on the same grid cell. Try:

<Grid DockPanel.Dock="Bottom">
    <Grid.ColumnDefinitions>
        <ColumnDefinition/>
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>
    <Button Grid.Column="0" Height="55"></Button>
    <Button Grid.Column="1" Height="55"></Button>
</Grid>

---

you can use StackPanel Instead of DockPanle like this:

<StackPanel Orientation="Vertical">
        <Button Height="55"/>
        <Button Height="55"/>
</StackPanel>