eCIA/eCIAv2.WindowsApp/Forms/MainForm.cs

using eCIAv2.Library.Devices;
using eCIAv2.Library.Devices.DIIO;
using eCIAv2.Library.Devices.Scanner;
using eCIAv2.WindowsApp.ViewModels;
using Microsoft.Extensions.DependencyInjection;
using System.Runtime.InteropServices;
using static System.Net.Mime.MediaTypeNames;

namespace eCIAv2.WindowsApp
{
    public partial class MainForm : Form
    {
        #region Custom TitleBar

        [DllImport("user32.dll")]
        public static extern bool ReleaseCapture();

        [DllImport("user32.dll")]
        public static extern IntPtr SendMessage(
            IntPtr hWnd, int Msg, int wParam, int lParam);

        private Panel titleBar;     

        private void CreateCustomTitle()
        {
            this.FormBorderStyle = FormBorderStyle.None;
            this.WindowState = FormWindowState.Maximized;
            this.MinimumSize = new Size(600, 400);

            titleBar = new Panel();
            titleBar.Height = 36;
            titleBar.Dock = DockStyle.Top;
            titleBar.BackColor = Color.FromArgb(40, 40, 40);

            titleBar.MouseDown += TitleBar_MouseDown;         

            this.Controls.Add(titleBar);

            CreateTitleIcon();
            CreateTitleLabel();
            CreateButtons();            
        }

        private void CreateTitleIcon()
        {
            PictureBox icon = new PictureBox();

            icon.Image = this.Icon.ToBitmap();
            icon.SizeMode = PictureBoxSizeMode.StretchImage;
            icon.Size = new Size(20, 20);
            icon.Location = new Point(8, 8);

            titleBar.Controls.Add(icon);
        }

        private void CreateTitleLabel()
        {
            Label lbl = new Label();

            lbl.Text = this.Text;
            lbl.ForeColor = Color.White;
            lbl.AutoSize = true;
            lbl.Location = new Point(36, 9);

            titleBar.Controls.Add(lbl);
        }

        private void CreateButtons()
        {
            Button btnClose = CreateTitleButton("X");      
            btnClose.Click += (s, e) => this.Close();

            Button btnMax = CreateTitleButton("<22><>");
            btnMax.Click += (s, e) =>
            {
                ToggleMaximize();
            };

            Button btnMin = CreateTitleButton("<22><>");
            btnMin.Click += (s, e) =>
            {
                this.WindowState = FormWindowState.Minimized;
            };
        
            titleBar.Controls.Add(btnMin);
            titleBar.Controls.Add(btnMax);
            titleBar.Controls.Add(btnClose);
        }

        private Button CreateTitleButton(string text)
        {
            Button btn = new Button();

            btn.Text = text;
            btn.Dock = DockStyle.Right;
            btn.Width = 45;
            btn.FlatStyle = FlatStyle.Flat;
            btn.FlatAppearance.BorderSize = 0;
            btn.ForeColor = Color.White;
            btn.BackColor = Color.FromArgb(40, 40, 40);           

            btn.MouseEnter += (s, e) =>
            {
                btn.BackColor = Color.FromArgb(70, 70, 70);
            };

            btn.MouseLeave += (s, e) =>
            {
                btn.BackColor = Color.FromArgb(40, 40, 40);
            };

            return btn;
        }

        private void TitleBar_DoubleClick(object sender, EventArgs e)
        {
            ToggleMaximize();
        }

        private void TitleBar_MouseDown(object sender, MouseEventArgs e)
        {
            ReleaseCapture();
            SendMessage(this.Handle, 0xA1, 0x2, 0);
        }

        private void ToggleMaximize()
        {
            if (this.WindowState == FormWindowState.Normal)
                this.WindowState = FormWindowState.Maximized;
            else
                this.WindowState = FormWindowState.Normal;
        }

        protected override void WndProc(ref Message m)
        {
            const int HTLEFT = 10;
            const int HTRIGHT = 11;
            const int HTTOP = 12;
            const int HTTOPLEFT = 13;
            const int HTTOPRIGHT = 14;
            const int HTBOTTOM = 15;
            const int HTBOTTOMLEFT = 16;
            const int HTBOTTOMRIGHT = 17;

            const int WM_NCHITTEST = 0x84;

            const int resizeArea = 8;

            if (m.Msg == WM_NCHITTEST)
            {
                base.WndProc(ref m);

                if ((int)m.Result == 0x01)
                {
                    Point pos = this.PointToClient(new Point(m.LParam.ToInt32()));

                    if (pos.X <= resizeArea && pos.Y <= resizeArea)
                        m.Result = (IntPtr)HTTOPLEFT;

                    else if (pos.X >= Width - resizeArea && pos.Y <= resizeArea)
                        m.Result = (IntPtr)HTTOPRIGHT;

                    else if (pos.X <= resizeArea && pos.Y >= Height - resizeArea)
                        m.Result = (IntPtr)HTBOTTOMLEFT;

                    else if (pos.X >= Width - resizeArea && pos.Y >= Height - resizeArea)
                        m.Result = (IntPtr)HTBOTTOMRIGHT;

                    else if (pos.X <= resizeArea)
                        m.Result = (IntPtr)HTLEFT;

                    else if (pos.X >= Width - resizeArea)
                        m.Result = (IntPtr)HTRIGHT;

                    else if (pos.Y <= resizeArea)
                        m.Result = (IntPtr)HTTOP;

                    else if (pos.Y >= Height - resizeArea)
                        m.Result = (IntPtr)HTBOTTOM;
                }

                return;
            }

            base.WndProc(ref m);
        }

        protected override void OnHandleCreated(EventArgs e)
        {
            base.OnHandleCreated(e);

            var screen = Screen.FromHandle(this.Handle);
            this.MaximizedBounds = screen.WorkingArea;
        }

        #endregion

        private readonly MainFromViewModel _vm;

        public MainForm(MainFromViewModel vm)
        {
            InitializeComponent();
            CreateCustomTitle();

            _vm = vm;
        }
    }
}