SSSnew/SSS/IzmenPar.xaml

<Page x:Class="SSS.IzmenPar"
      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:SSS"
      mc:Ignorable="d" 
      d:DesignHeight="450" d:DesignWidth="800"
      Title="IzmenPar">

    <Grid Background="#F5F5F5">
        <Grid.RowDefinitions>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="35"></RowDefinition>
        </Grid.RowDefinitions>
        <StackPanel Margin="0,80,0,0"  Width="300" Grid.Row="0">
            <TextBlock Text="Логин" Background="#0000" Margin="0,0,0,0"></TextBlock>
            <TextBox Background="#0000" Foreground="Black"  Name="Login"></TextBox>

            <TextBlock Text="Пароль" Background="#0000" Margin="0,5,0,0"></TextBlock>
            <TextBox Background="#0000" Foreground="Black"  Name="Pass"></TextBox>

            <Border BorderThickness="2" CornerRadius="7"  Background="White" Height="30" Margin="0,5,0,0">
                <Button  BorderBrush="#0000" Foreground="Black" FontSize="14" Click="FixChange">Изменить</Button>
            </Border>
        </StackPanel>
        <StackPanel Grid.Row="1" VerticalAlignment="Center" HorizontalAlignment="Left" Margin="3,0,0,0">
            <Border BorderThickness="2" CornerRadius="7" BorderBrush="#0000" Background="White" Width="100" Height="30">
                <Button   Foreground="Black" Content="Назад" FontSize="16" Click="Back"></Button>
            </Border>
        </StackPanel>
    </Grid>
</Page>