Windows CE Programming

If you are running a kiosk mode app but need to provide the camercapture dialog on Windows Mobile 5 or later, you may need to disable the one or other click in the CameraCapture dialog.

This article uses a technique known as subclassing as already used and decribed in my StartButtonHookWM65 article. For the CameraCapture dialog the code has been revised and you can now subclass any known window class and disable clicks within the Windows Mobile menu bar.

        private string _winClassName = "HHTaskbar";
        public string winClassName
        {
            get { return _winClassName; }
            set {
                if (this.oldWndProc == IntPtr.Zero) //only allow change before subclassing
                    _winClassName = value;
            }
        }
...
        /// <summary>
        /// SubClassing: Install the wndproc hook
        /// </summary>
        /// <returns></returns>
        private bool hookWindow()
        {
            //find the window to hook
            IntPtr hWndHooked = FindWindow(_winClassName, IntPtr.Zero);
            if (hWndHooked == IntPtr.Zero)
                return false;
            //enable the taskbar, not realy necessary
            EnableWindow(hWndHooked, true);
            //already installed?
            if (oldWndProc == IntPtr.Zero)
            {
                //find the menu_worker window
                IntPtr hwndMenu_Worker = FindWindow("menu_worker", IntPtr.Zero);
                if (hwndMenu_Worker != IntPtr.Zero)
                {
                    //get the child window which has the buttons on it
                    IntPtr hwndToolbar = GetWindow(hwndMenu_Worker, GetWindow_Cmd.GW_CHILD);
                    if (hwndToolbar != IntPtr.Zero)
                    {
                        _mHwnd = hwndToolbar;       //store to remember
                        SubclassHWnd(hwndToolbar);  //subclass the wndproc
                    }
                }
            }
            return true;
        }

As the call to CameraCaptureDialog will block and you can not subclass it before it is launched, I use a timer that will subclass the dialog assuming it will show after the call to .ShowDialog().

        private System.Windows.Forms.Timer timer;
        hwndutils subClassUtils;
        private void ShowCamera()
        {
            CameraCaptureDialog cdlg = new CameraCaptureDialog();
            cdlg.DefaultFileName="picture.jpg";
            cdlg.InitialDirectory = "\\My Documents";
            cdlg.Mode = CameraCaptureMode.Still;
            cdlg.Owner = this.pictureBox1;
            cdlg.StillQuality = CameraCaptureStillQuality.High;
            cdlg.Title = "Take a picture and Select";
            cdlg.Resolution = new Size(240, 320);
            cdlg.VideoTypes = CameraCaptureVideoTypes.All;

            //subclass main window with delay
            subClassUtils = new hwndutils();
            timer = new Timer();
            timer.Interval = 1000;
            timer.Tick += new EventHandler(timer_Tick);
            timer.Enabled = true;

            DialogResult dRes = cdlg.ShowDialog();
...
        void timer_Tick(object sender, EventArgs e)
        {
            subClassUtils.winClassName = "Camera View";
            subClassUtils.CloseButtonDisabled = true;
            System.Threading.Thread.Sleep(500);
            if(subClassUtils.CloseButtonDisabled)
                timer.Enabled = false;

        }

In the line “subClassUtils.CloseButtonDisabled = true;” the subclassing (or the hook) will be activated and clicks on (OK) will not be accepted.

Code subclassing.cs download: [Download not found]

Are you looking for a tool that periodically pings a list of hosts? Here is a toolset that will reschedule a ping utilitiy. This ping utility pings a list of hosts and will create notifications if one or most hosts failed to answer.

I have done this toolset with three separate applications. The scheduler and the notification tool are written in C/C++ win32 API cause this API provided the best access to all the possibilities of the used functions. The user notification API is only supported with basic functionality by CF2. The CEUserNotification API is not supported by CF2 at all.

Although OpenNetCF provides an C# interface to the used APIs, I did not like to include all the unneeded stuff. On the other hand the scheduler is fast and small written in C/C++. With C# I had problems with the notification, especially for removing existing notifications and why should the main tool reside in memory just for showing the notification.

The ping tool is written in C# targeting Compact Framework 2. C# was the easiest to implement the GUI.

All source is available thru one Visual Studio 2008 solution. Yes, you can mix C/C++ and CF2 within one solution.

Continue reading ‘Mobile Development-PingAlert: watch your servers’ »

Hello Readers

it has been a long time since my last post, I was a little bit busy.

This time I want to present some experimental code to visualize and analyze G-Sensor data. The goal was to achieve a shake detection algorithm. Unfortunately the device under test only provided 1 sample per second and that is not enough for a good shake detection. Beside that the code and classes developed may help you to find your way and they help you at last to determine the current orientation of the device.

left shows general information taken from vector, right shows a log with last vector data

[image SensorScan5_0102.gif]

[image SensorScan5_0304.gif]
left shows graphical of vector and force (length), right shows indicators for detected events

A g-sensor or accelerometer sensor normally gives you the x, y and z-values of a vector. A vector is an imaginary arrow with a direction and length starting from the three dimensional point 0,0,0. The vector direction points to the acceleration of the device. The normal acceleration on earth is 9,81m/s^2. If the device is on the desk, the y-acceleration is about minus 9.81m/s^2. The absolute value of the sensor may vary on the sensor and maybe defined as 1.0 for -9.81m/s^2 or -0.981. If you through the device up to the air, the x,y and z-values will reach 0,0,0 as if the device is weightless. Keep in mind that the acceleration towards the middle of the earth is always there and the device will come back to you.

Here is another visualization of the vector and a device (done with visual python, [Download not found]):

[image vectors.gif]

The device is facing upwards (see y arrow) with the top facing to you (the z arrow). The left side of the device is pointing to the right (the x arrow).

The light green/blue and the yellow arrows demonstrate two different vectors which show the direction (the xyz angles) and the force (the vector lengths) to the device.

Continue reading ‘Mobile Development – Shake that thing’ »

The famous rdesktop running natively on windows ce and windows mobile

Intro and Background

Some times ago I found that message of Jay Sorg and retrieved a copy of his code for a native rdesktop win32 version. I played a little and got the code compile with Visual Studio 2005 with the Windows Mobile SDK.

I tried to implement windows clipboard support to enhance the transfer of texts between the client and server, but unfortunately I was not successful yet. Hopefully someone jumps in and helps enhancing the code and adds some features.

Rdesktop is open source and you can go with the wince implementation here, but if it does not work for you, you have either change the code yourself (and publish it) or find someone that is able to do for you.

There is a template uiports/xxxwin.c in the actual rdesktop source you can use as a starter to compile the actual rdesktop version for windows mobile if you manage to get all the dependencies to work. If you success, forget this post and go with this version (maybe you leave me a note?).

Why another Remote Desktop/Terminal Server Client?

Continue reading ‘Mobile Development: a native remote desktop client (rdesktop port win32)’ »