savelev_avt/Pages/AuthPage.xaml

<Page x:Class="savelev_avtor.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:savelev_avtor.Pages"
      mc:Ignorable="d" 
      d:DesignHeight="450" d:DesignWidth="800"
      Title="Авторизация">

    <Grid Background="#FFFDFDFD">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="80*"/>
            <ColumnDefinition Width="129*"/>
            <ColumnDefinition Width="507*"/>
            <ColumnDefinition Width="84*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="25*"/>
            <RowDefinition Height="344*"/>
            <RowDefinition Height="81*"/>
        </Grid.RowDefinitions>
        <Label Content="Логин" Margin="10,53,0,0" Grid.Row="1" Grid.Column="1" HorizontalAlignment="Left" Width="109" Height="23" VerticalAlignment="Top"/>
        <TextBox x:Name="TextBoxLogin" Grid.Column="2" HorizontalAlignment="Left" Height="23" Grid.Row="1" TextWrapping="Wrap"  VerticalAlignment="Top" Width="120" Margin="10,53,0,0"/>
        <Label Content="Пароль" Grid.Column="1" Margin="10,82,0,0" Grid.Row="1" HorizontalAlignment="Left" Width="109" Height="23" VerticalAlignment="Top"/>
        <Button Content="Вход" Grid.Column="2" HorizontalAlignment="Left" Margin="10,110,0,0" Grid.Row="1" VerticalAlignment="Top" Width="120" Height="20" Click="ButtonEnter_OnClick"/>
        <Button Content="Регистрация" Grid.Column="2" HorizontalAlignment="Left" Margin="10,135,0,0" Grid.Row="1" VerticalAlignment="Top" Width="120" Height="20" Click="ButtonRegistartion_OnClick"/>
        <PasswordBox x:Name="PasswordBox" Grid.Column="2" HorizontalAlignment="Left" Margin="10,82,0,0" Grid.Row="1" VerticalAlignment="Top" Width="120" Height="23"/>

    </Grid>
</Page>