Basic c# console app for showing a toast notification.

toast.cs

using Windows.Data.Xml.Dom;
using Windows.UI.Notifications;

namespace ToastDesktop
{
    internal class Program
    {
        /// You have to add in the .csproj:
        /// <TargetPlatformVersion>10.0.10240.0</TargetPlatformVersion>
        /// I always put it in the <PropertyGroup/> which contains the <TargetFrameworkVersion/>.
        ///
        /// References to add :
        /// - Windows.UI
        /// - Windows.Data
        private static void Main(string[] args)
        {
            string xml = $@"
                <toast>
                    <visual>
                        <binding template='ToastGeneric'>
                            <text>Some title</text>
                            <text>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</text>
                        </binding>
                    </visual>
                </toast>";

            XmlDocument doc = new XmlDocument();
            doc.LoadXml(xml);

            ToastNotification toast = new ToastNotification(doc);
            toast.Tag = "tag";
            toast.Group = "group";

            ToastNotificationManager.CreateToastNotifier("ToastDesktop").Show(toast);
        }
    }
}

For this to work with Windows 10 you must add a reference to: C:\Program Files (x86)\Windows Kits\10\References\Windows.Foundation.UniversalApiContract\1.0.0.0\Windows.Foundation.UniversalApiContract.winmd