The System.Windows.Controls.Grid control is one of the most commonly used containers in Silverlight. It allows you to organize its content into rows and columns as a regular grid. By default a Grid control has only one cell and everything you add goes there overlapping the previous content. In order to define multiple rows and columns to your Grid control you have to add as many <RowDefinition> and <ColumnDefinition> as you need, see the sample below.
Xaml
<Page
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Grid x:Name="MyGrid" ShowGridLines="True">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
</Grid>
</Page>
C#
Grid MyGrid = new Grid();
RowDefinition row1 = new RowDefinition();
RowDefinition row2 = new RowDefinition();
RowDefinition row3 = new RowDefinition();
MyGrid.RowDefinitions.Add( row1 );
MyGrid.RowDefinitions.Add( row2 );
MyGrid.RowDefinitions.Add( row3 );
ColumnDefinition col1 = new ColumnDefinition();
ColumnDefinition col2 = new ColumnDefinition();
ColumnDefinition col3 = new ColumnDefinition();
MyGrid.ColumnDefinitions.Add( col1 );
MyGrid.ColumnDefinitions.Add( col2 );
MyGrid.ColumnDefinitions.Add( col3 );
As you can see we have added 3 rows and 3 columns definitions in our Grid control. So finally what we get is a grid with 9 cells ordered 3x3.
That's it!