gff/Pages/AuthPage.xaml

<Page x:Class="IS31Nabievv.Pages.AuthPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:local="clr-namespace:IS31Nabievv.Pages"
      mc:Ignorable="d" 
      d:DesignHeight="450" d:DesignWidth="800"
      Title="AuthPage">

    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="5*"/>
            <ColumnDefinition Width="9*"/>
            <ColumnDefinition Width="6*"/>
        </Grid.ColumnDefinitions>
        <Label Content="Логин" HorizontalAlignment="Right" Margin="0,63,231,0" VerticalAlignment="Top" Height="22" Width="72" Grid.Column="1"/>
        <TextBox x:Name="TextBoxLogin" HorizontalAlignment="Left" Height="22" Margin="128.899,63,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="192" TextChanged="TextBox_TextChanged" Grid.Column="1"/>
        <Label Content="Пароль" HorizontalAlignment="Right" Margin="0,90,231,0" VerticalAlignment="Top" Height="22" Width="72" Grid.Column="1"/>
        <PasswordBox x:Name="PasswordBox" HorizontalAlignment="Left" Height="22" Margin="128.899,90,0,0" VerticalAlignment="Top" Width="192" Grid.Column="1"/>
        <Button Content="Вход" HorizontalAlignment="Left" Margin="128.899,117,0,0" VerticalAlignment="Top" Width="192" Height="22" Grid.Column="1" Click="Button_Click"/>
        <Button Content="Регистрация" HorizontalAlignment="Left" Margin="128.899,144,0,0" VerticalAlignment="Top" Width="192" Height="22" Grid.Column="1"/>

    </Grid>
</Page>