test/QualTask/UserWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        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="800" d:DesignHeight="450"
        x:Class="QualTask.UserWindow"
        Title="UserWindow">
    <Grid>
        <DataGrid x:Name="UsersDataGrid" IsReadOnly="True">
            <DataGrid.Columns>
                <DataGridTextColumn Header="Имя"  Binding="{Binding Fname}"/>
                <DataGridTextColumn Header="Фамилия"  Binding="{Binding Lname}"/>
                <DataGridTextColumn Header="Логин"  Binding="{Binding Login}"/>
                <DataGridTextColumn Header="Роль"  Binding="{Binding Role}"/>
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
</Window>