single cs file for winfrom by csc.exe from cli

top-win.cs

using System; // Console
using System.Runtime.InteropServices; // DllImport、StructLayout
using System.Windows.Forms; // Screen、Form
using System.Drawing; // Rectangle
using System.ComponentModel;
using System.Diagnostics; // Process

/**
 * https://docs.microsoft.com/en-us/dotnet/framework/app-domains/how-to-build-a-single-file-assembly
 * https://docs.microsoft.com/zh-cn/dotnet/csharp/language-reference/compiler-options/command-line-building-with-csc-exe
 * https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/inside-a-program/hello-world-your-first-program
 * https://docs.microsoft.com/en-us/dotnet/framework/winforms/how-to-create-a-windows-forms-application-from-the-command-line
 * https://stackoverflow.com/a/24406318/6528523
 * https://stackoverflow.com/questions/5282588/how-can-i-bring-my-application-window-to-the-front
 */
namespace TopWin
{
    public class Form1 : Form
    {
        [DllImport("user32.dll")]
        private static extern bool GetWindowRect(HandleRef hWnd, [In, Out] ref RECT rect);

        [DllImport("user32.dll")]
        private static extern IntPtr GetForegroundWindow();

        [StructLayout(LayoutKind.Sequential)]
        private struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }
        
        public static bool IsAnyWindowFullScreen()
        {
            RECT rect = new RECT();
            GetWindowRect(new HandleRef(null, GetForegroundWindow()), ref rect);
            return new Rectangle(rect.left,
                rect.top,
                rect.right - rect.left,
                rect.bottom - rect.top
            ).Contains(Screen.PrimaryScreen.Bounds);
        }
        
        [DllImport("User32.dll", SetLastError = true)]
        private static extern void SwitchToThisWindow(IntPtr hWnd, bool fAltTab);
        
        [DllImport("User32.dll")]
        public static extern Int32 SetForegroundWindow(int hWnd); 
        
        //////////////////////////////////////////
        
        public Button button1;
        private System.Timers.Timer timer;
        private void button1_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
            this.BringToFront();
            this.Show();
            this.WindowState = FormWindowState.Normal;
            MessageBox.Show("Hello World");
        }
        private void OnTimedEvent(Object source, System.Timers.ElapsedEventArgs e)
        {
            Process currentProcess = Process.GetCurrentProcess();
            // SwitchToThisWindow(currentProcess.MainWindowHandle, true);
            SetForegroundWindow(currentProcess.MainWindowHandle.ToInt32());
        }
        public Form1()
        {
            button1 = new Button();
            button1.Size = new Size(40, 40);
            button1.Location = new Point(30, 30);
            button1.Text = "Click me";
            this.Controls.Add(button1);
            button1.Click += new EventHandler(button1_Click);
            
            // Create a timer with a 1 millisecond interval.
            timer = new System.Timers.Timer(1000 * 1); // 1 second
            timer.Elapsed += this.OnTimedEvent;
            // Hook up the Elapsed event for the timer. 
            timer.AutoReset = true;
            Console.WriteLine("The timer should fire every {0} * 1000 milliseconds.", timer.Interval);
            timer.Enabled = true;
        }
        
        [STAThread]
        static void Main(string[] args) 
        {
            string csc_exe = @"C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe";
            string cs_file = @"C:\Users\312\Desktop\top-win.cs";
            Console.WriteLine(csc_exe + " " + cs_file);

            // Keep the console window open in debug mode.
            Console.WriteLine("Press any key to show window.");
            Console.ReadKey();
            
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            
            Form1 form = new Form1();
            form.StartPosition = FormStartPosition.CenterScreen;
            if(!IsAnyWindowFullScreen())
            {
                Console.WriteLine("IsAnyWindowFullScreen() == false");
                // form.Hide();
                form.TopMost = true;
            }
            // form.Show();
            Application.Run(form);
            
            // https://pypi.org/project/websockets/
            // https://github.com/aaugustin/websockets
        }
    }
}

build with command line(maybe need to change v4.0.30319 to another version number):

C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe C:\Users\312\Desktop\top-win.cs