mdk-01.01-school/school/FolderWindows/MainWindow.xaml

<Window x:Class="school.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:school"
        mc:Ignorable="d"
        Title="Леарн" MinHeight="450" MinWidth="800"
        Height="450" Width="800"
        Icon ="\Resource\school_logo.ico">
    <Grid>
        <Frame Name="mainFrame" NavigationUIVisibility="Hidden"/>
    </Grid>
</Window>