sql/wpf_connection3/Windows/EditingMaterialWindow.xaml

<Window x:Class="wpf_connection3.Windows.EditingMaterialWindow"
        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:wpf_connection3.Windows"
        mc:Ignorable="d"
       Title="Добавление материала" Height="170" Width="400">
    <Grid>
        <StackPanel
            Orientation="Vertical"
            HorizontalAlignment="Center">
            <Label
                    Content="Материал"/>
            <ComboBox
                    Name="MaterialTypeComboBox"
                    Width="200"
                    ItemsSource="{Binding MaterialList}"
                    SelectedIndex="0"/>
            <Label
                    Content="Количество"/>
            <TextBox
                    Width="200"
                    Text="0"
                    x:Name="CountTextBox"/>
            <Button
                    Name="SaveButton"
                    Content="Добавить материал"
                    Margin="0,15"
                    Click="SaveButton_Click"/>
        </StackPanel>
    </Grid>
</Window>