DP44/DataPRO/DASFactory/DASFactory.WindowsNotification.cs

using System;
using System.Collections.Concurrent;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using DTS.Common.USBFramework;
using DTS.Common.Utilities.Logging;

namespace DTS.DASLib.DASFactory
{
    internal abstract class WindowsNotification : DeviceHandling
    {
        protected FileIODeclarations.SECURITY_ATTRIBUTES Security;
        protected DeviceManagement MyDeviceManagement;

        protected Guid DeviceGuid = Guid.Empty;

        /// <summary>
        /// Handle of the window which receives messages from Windows. This will be a form.
        /// </summary>
        protected IntPtr RecipientHandle;
        protected IntPtr DeviceNotifyHandle;
        protected NotificationForm NotificationWindow;

        protected WindowsNotification(DASFactory _factory,
                                   UpdateFinishedEventHandler _SerialUpdateFinished,
                                   Guid _guid,
                                   BlockingCollection<Tuple<QueueActions, DeviceHandling>> queueActionPerDevice
                                   )
            : base(_factory, _SerialUpdateFinished, queueActionPerDevice)
        {
            MyDeviceManagement = new DeviceManagement();
            Security = new FileIODeclarations.SECURITY_ATTRIBUTES
            {
                lpSecurityDescriptor = 0,
                bInheritHandle = Convert.ToInt32(true)
            };
            Security.nLength = Marshal.SizeOf(Security);

            DeviceGuid = _guid;

            NotificationWindow = new NotificationForm(NotificationWndProc);
            NotificationWindow.Show(); // will be hidden immediately
            DeviceNotifyHandle = IntPtr.Zero;
            RecipientHandle = NotificationWindow.Handle;

            if (!MyDeviceManagement.RegisterForDeviceNotifications(RecipientHandle,
                                                                  DeviceGuid,
                                                                  ref DeviceNotifyHandle))
            {
                throw new Exception("DASFactory.WindowsNotification: Unable to register device");
            }
        }

        public override void Dispose()
        {
            if (DeviceNotifyHandle != IntPtr.Zero)
            {
                MyDeviceManagement.StopReceivingDeviceNotifications(DeviceNotifyHandle);
            }
            try
            {
                /*if (null != NotificationWindow)
                {
                    if (NotificationWindow.InvokeRequired)
                    {
                        NotificationWindow.Invoke(new Action(() =>
                            {
                                if (NotificationWindow.IsHandleCreated)
                                {
                                    NotificationWindow.Close();
                                    NotificationWindow.Dispose();
                                    NotificationWindow = null;
                                }
                            }));
                    }
                    else
                    {
                        if (NotificationWindow.IsHandleCreated)
                        {
                            NotificationWindow.Close();
                            NotificationWindow.Dispose();
                            NotificationWindow = null;
                        }
                    }
                }*/
                /* Cross-thread operation not valid: Control 'NotificationForm' accessed from a thread other than the thread it was created on. */
                //NotificationWindow.Close();
            }
            catch (Exception ex) { APILogger.Log(ex.Message); }
            base.Dispose();
        }

        /// <summary>
        /// This gets called whenever anything happens to WinUSB devices
        /// </summary>
        /// <param name="m">The windows message</param>
        protected virtual void NotificationWndProc(ref Message m)
        {
            //we detect the media arrival event
            if (m.Msg != DeviceManagementDeclarations.WM_DEVICECHANGE)
            {
                return;
            }
            if (m.WParam.ToInt32() == DeviceManagementDeclarations.DBT_DEVICEARRIVAL)
            {
                if (Marshal.ReadInt32(m.LParam, 4) == DeviceManagementDeclarations.DBT_DEVTYP_DEVICEINTERFACE)
                {
                    NotificationDeviceArrived(ref m);
                }
            }
            else
            {
                if (m.WParam.ToInt32() == DeviceManagementDeclarations.DBT_DEVICEREMOVECOMPLETE)
                {
                    if (Marshal.ReadInt32(m.LParam, 4) == DeviceManagementDeclarations.DBT_DEVTYP_DEVICEINTERFACE)
                    {
                        NotificationDeviceRemoved(ref m);
                    }
                }
            }
        }

        protected abstract void NotificationDeviceArrived(ref Message m);

        protected abstract void NotificationDeviceRemoved(ref Message m);

        /// <summary>
        /// Hidden Form which we use to receive Windows messages
        /// </summary>
        internal class NotificationForm : Form
        {
            public delegate void WinMsgProc(ref Message m);

            private Label label1;
            private readonly WinMsgProc mDetector;

            /// <summary>
            /// Set up the hidden form. 
            /// </summary>
            /// <param name="detector">DriveDetector object which will receive notification about USB drives, see WndProc</param>
            public NotificationForm(WinMsgProc detector)
            {
                mDetector = detector;
                MinimizeBox = false;
                MaximizeBox = false;
                ShowInTaskbar = false;
                ShowIcon = false;
                FormBorderStyle = FormBorderStyle.FixedToolWindow;
                Load += Load_Form;
                Activated += Form_Activated;
            }

            private void Load_Form(object sender, EventArgs e)
            {
                // We don't really need this, just to display the label in designer ...
                InitializeComponent();

                // Create really small form, invisible anyway.
                Size = new Size(5, 5);
            }

            private void Form_Activated(object sender, EventArgs e)
            {
                //this.Visible = false;
            }

            /// <summary>
            /// This function receives all the windows messages for this window (form).
            /// We call the DASFactory from here so that is can pick up the messages
            /// </summary>
            protected override void WndProc(ref Message m)
            {
                base.WndProc(ref m);

                if (mDetector != null)
                {
                    mDetector(ref m);
                }
            }

            private void InitializeComponent()
            {
                label1 = new Label();
                SuspendLayout();
                // 
                // label1
                // 
                label1.AutoSize = true;
                label1.Location = new Point(13, 30);
                label1.Name = "label1";
                label1.Size = new Size(314, 13);
                label1.TabIndex = 0;
                label1.Text = @"This is an invisible form.";
                // 
                // DetectorForm
                // 
                ClientSize = new Size(360, 80);
                Controls.Add(label1);
                Name = "NotificationForm";
                Opacity = 0;
                ResumeLayout(false);
                PerformLayout();

            }
        }
    }
}