Silverlight - Layout Question

I am creating a Silverlight application that should take up the width of the user's screen. This application has a horizontal row that greets the user. Then, two columns below it. The right column is always a fixed size. I want the left column to take up any remaining space. In an attempt to accomplish this, I am using the following XAML:

<Grid x:Name="layoutRoot" Background="White">
  <Grid.RowDefinitions>
    <RowDefinition Height="Auto" />
    <RowDefinition />
  </Grid.RowDefinitions>

  <Grid x:Name="greetingGrid" Margin="0,0,0,8">            
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>

    <StackPanel Orientation="Horizontal">
      <TextBlock Text="Welcome " />
      <TextBlock x:Name="usernameTextBlock" />
    </StackPanel>            
  </Grid>    

  <Grid x:Name="contentGrid" Grid.Row="1">            
    <Grid.ColumnDefinitions>
      <ColumnDefinition />
      <ColumnDefinition />
    </Grid.ColumnDefinitions>

    <Grid x:Name="leftGrid" HorizontalAlignment="Stretch">
      <Border x:Name="leftBorder" BorderBrush="Black" Height="250">
        <!-- Insert Wrap Panel of Images --!>
      </Border>
    </Grid>

    <Grid x:Name="rightGrid" Width="100" Grid.Column="1" HorizontalAlignment="Right" Margin="8,0,0,0">
      <Border BorderBrush="Black" BorderThickness="2">
        <开发者_高级运维StackPanel Orientation="Vertical">
      <TextBlock Text="How would you like to view the images?" />
      <ComboBox x:Name="optionComboBox">
        <ComboBoxItem Content="Name" />
        <ComboBoxItem Content="Date" />
      </ComboBox>
        </StackPanel>
      </Border>
    </Grid>
  </Grid>
</Grid>

Oddly, the two lower columns are split evenly in size. How do I make the left column take up all remaining space?

Thank you!

---

<Grid.ColumnDefinitions>
  <ColumnDefinition width="*" />
  <ColumnDefinition width="250"/>
</Grid.ColumnDefinitions>

Use * for the grid column to take the rest of the available space. Keep in mind that the parent container also needs to take the whole area to make it work!

---

You can specify the widths of the columns rather than on your "rightGrid", eg:

    <Grid x:Name="greetingGrid" Margin="0,0,0,8">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <StackPanel Orientation="Horizontal">
            <TextBlock Text="Welcome " />
            <TextBlock x:Name="usernameTextBlock" />
        </StackPanel>
    </Grid>

    <Grid x:Name="contentGrid" Grid.Row="1">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="100px" />
        </Grid.ColumnDefinitions>

        <Grid x:Name="leftGrid" HorizontalAlignment="Stretch" Background="Fuchsia">
            <Border x:Name="leftBorder" BorderBrush="Black" Height="250">

  </Border>
</Grid>

<Grid x:Name="rightGrid"  Grid.Column="1" HorizontalAlignment="Right" Margin="8,0,0,0">
  <Border BorderBrush="Black" BorderThickness="2">
    <StackPanel Orientation="Vertical">
  <TextBlock Text="How would you like to view the images?" />
  <ComboBox x:Name="optionComboBox">
    <ComboBoxItem Content="Name" />
    <ComboBoxItem Content="Date" />
  </ComboBox>
    </StackPanel>
  </Border>
</Grid>