Changing Grid Row background color in WPF

<Window x:Class="WpfApplication3.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <Border Background="Cyan" />
        <Border Grid.Row="2" Grid.Column="1"  Background="Red" />
        <Border  Grid.Row="1" Background="Black" />
        <Border  Grid.Row="1" Background="Black" />
        <Border Grid.Row="2" Background="Orange" />
        <Border Grid.Row="0" Grid.Column="1" Background="Green" />
        <TextBlock Grid.ColumnSpan="2" Grid.Row="1" Text="Here is some more text" HorizontalAlignment="Center"  VerticalAlignment="Center"/>
        <TextBlock Grid.ColumnSpan="2" Text="Here is some text" HorizontalAlignment="Center"  VerticalAlignment="Center"/>
        <TextBlock Grid.ColumnSpan="2" Grid.Row="2" Text="Here is even more text" HorizontalAlignment="Center"  VerticalAlignment="Center"/>
    </Grid>
</Window>
![enter image description here][1]


  [1]: http://i.stack.imgur.com/LX9X8.png

Use Rectangles to fill the rows first, then add data to them.

    <Grid Background="White">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <Rectangle Grid.Row="0" Fill="AliceBlue" />
        <TextBlock Grid.Row="0" Text="Row 1" HorizontalAlignment="Center"/>
        <Rectangle Grid.Row="1" Fill="AntiqueWhite" />
        <TextBlock Grid.Row="1" Text="Row 2" HorizontalAlignment="Center"/>
        <Rectangle Grid.Row="2" Fill="AliceBlue" />
        <TextBlock Grid.Row="2" Text="Row 3" HorizontalAlignment="Center"/>
        <Rectangle Grid.Row="3" Fill="AntiqueWhite" />
        <TextBlock Grid.Row="3" Text="Row 4" HorizontalAlignment="Center"/>
    </Grid>

Edit: If you're loading an unknown amount of items, then i think you need something like an itemscontrol to load them in. You can then use the alternationcount and triggers to handle the alternating color.

    <ItemsControl ItemsSource="{Binding DataList}" AlternationCount="2">
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <Grid x:Name="FooBar" Margin="0,0,0,10">

                </Grid>
                <DataTemplate.Triggers>
                    <Trigger Property="ItemsControl.AlternationIndex" Value="0">
                        <Setter Property="Background" Value="Blue" TargetName="FooBar"/>
                    </Trigger>
                    <Trigger Property="ItemsControl.AlternationIndex" Value="1">
                        <Setter Property="Background" Value="Red" TargetName="FooBar"/>
                    </Trigger>
                </DataTemplate.Triggers>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>