Create nested StackPanel
s which contain the required number of items.
In the example below, you have two rows, respectively occupied by the <StackPanel Orientation="Horizontal">
elements, which in turn each contain five items that will be displayed horizontally next to each other.
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal">
<Item1 />
<Item2 />
<Item3 />
<Item4 />
<Item5 />
</StackPanel>
<StackPanel Orientation="Horizontal">
<Item1 />
<Item2 />
<Item3 />
<Item4 />
<Item5 />
</StackPanel>
</StackPanel>