test1/WpfApp5/WindowSupplier.xaml

<Window x:Class="WpfApp5.WindowSupplier"
        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"
        xmlns:local="clr-namespace:WpfApp5"
        mc:Ignorable="d"
        Title="Таблица с продавцами" Height="450" Width="800">
    <Grid>
        <ScrollViewer>
            <StackPanel>
                <Button Name="button" Content="кнопка" Click="button_Click"/>
                <DataGrid Name="tableMatetial"/>
            </StackPanel>
        </ScrollViewer>
    </Grid>
</Window>