Define rows / columns for Grid
<UserControl x:Class='SilverlightApplication3.MainPage' xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' xmlns:d='http://schemas.microsoft.com/expression/blend/2008' xmlns:mc='http://schemas.openxmlformats.org/markup-compatibility/2006' mc:Ignorable='d' d:DesignWidth='640' d:DesignHeight='480'> <Grid ShowGridLines ="True" Background ="AliceBlue"> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition/> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition/> <RowDefinition/> </Grid.RowDefinitions> <TextBlock Name="lblInstruction" Grid.Column ="0" Grid.Row ="0" FontSize="15">Enter</TextBlock> <Button Name="btnOK" Height ="30" Grid.Column ="0" Grid.Row ="0" >OK</Button> <TextBlock Name="lblMake" Grid.Column ="1" Grid.Row ="0">Make</TextBlock> <TextBox Name="txtMake" Grid.Column ="1" Grid.Row ="0" Width="193" Height="25"/> <TextBlock Name="lblColor" Grid.Column ="0" Grid.Row ="1" >Color</TextBlock> <TextBox Name="txtColor" Width="190" Height="25" Grid.Column ="0" Grid.Row ="1" /> <Rectangle Fill ="LightGreen" Grid.Column ="1" Grid.Row ="1" /> <TextBlock Name="lblPetName" Grid.Column ="1" Grid.Row ="1" >Name</TextBlock> <TextBox Name="txtPetName" Grid.Column ="1" Grid.Row ="1" Width="193" Height="25"/> </Grid> </UserControl>