Podgotovka_K_Demo/WpfApp10/MainWindow.xaml

<Window x:Class="WpfApp10.MainWindow"
        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:WpfApp10"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <StackPanel>
            <TextBox x:Name="log"></TextBox>
            <TextBox x:Name="par"></TextBox>
            <Button x:Name="prov" Content="Проверить" Click="prov_Click"></Button>
            <StackPanel x:Name="captcha" Visibility="Hidden">
                <Grid x:Name="ris" SizeChanged="ris_SizeChanged" Background="AliceBlue" Width="200" Height="60">
                    
                </Grid>
                <Button Content="Помеянть" Click="Button_Click"></Button>
                <TextBox x:Name="txt"></TextBox>
            </StackPanel>
        </StackPanel>
    </Grid>
</Window>