I’m just learning visual studio and already struggling. I can’t add WindowsBase.dll as a reference because I get an error that its automatically being referenced by the build system. But without adding it, I get an error, “Cannot find type System.Windows.DependencyObject in module WindowsBase.dll. What am I missing?

Below is my code, it’s a copy from windows tutorial on writing a uwp app.

using System;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media;
using Windows.UI;

// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace SayHello
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        private Random rand;

        public MainPage()
        {
            this.InitializeComponent();
            rand = new Random();
        }

        private byte[] GetRandomBytes(int n)
        {
            var randomBytes = new byte[n];
            rand.NextBytes(randomBytes);
            return randomBytes;
        }
        private void SayHelloButton_Click(object sender, RoutedEventArgs e)
        {
            byte[] rgb = GetRandomBytes(3);

            var randomColorBrush = new SolidColorBrush(Color.FromArgb(255, rgb[0], rgb[1], rgb[2]));

            textBox1.BorderBrush = randomColorBrush;
            textBox1.Foreground = randomColorBrush;
        }
    }
}