Enable/disable WiFi with the .NET Compact Framework

In my first compact framework blog entry I want to show you how to programmatically enable and disable wifi on your device.
When I started programming for Windows Mobile I was surprised how much isn't directly available in the .NET compact framework but has to be accessed with function calls in the coredll.dll. I thought that something basic like controlling the volume or enabling/disabling the phone/bt or wifi is easily to do... but it isn't.

Here are the steps you have to perform to control the wifi device:
1. Get the name of the wifi device. It is located in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Power\State
Because there are more than just one values we are looking for the first subkey in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Power\State\Suspend which is on my device "{98C5250D-C29A-4985-AE5F-AFE5367E5006}"
Now, to get the complete name, let's find the first value in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Power\State which contains {98C5250D-C29A-4985-AE5F-AFE5367E5006}. This is on my Diamond "{98C5250D-C29A-4985-AE5F-AFE5367E5006}\TNETW12511"
This may sound a bit unreliable but it worked on all devices I saw ;-)
2. If we have found the correct name we call the coredll function SetDevicePower
3. Because on iPAQ devices everything works different, we have to call some other functions as well: iPAQSetWLANRadio which is located in ipaqutil.dll

Now here is the example:

using System;

using System.Collections.Generic;

using System.Text;

using System.Runtime.InteropServices;

using Microsoft.Win32;

namespace WifiTest

{

    public class WiFiCtrl

    {

        #region PInvokes

        [DllImport("ipaqutil.dll", SetLastError = true)]

        private static extern bool iPAQSetWLANRadio(ref int status);

        [DllImport("iPAQUtil.dll", SetLastError = true)]

        private static extern bool iPAQGetWLANRadioStatus(ref int val);

        [DllImport("coredll.dll", SetLastError = true)]

        private static extern int SetDevicePower(string pvDevice, int dwDeviceFlags, DevicePowerState DeviceState);

        [DllImport("coredll.dll", SetLastError = true)]

        private static extern int GetDevicePower(string pvDevice, int dwDeviceFlags, ref DevicePowerState DeviceState);

        #endregion

        private enum DevicePowerState : int

        {

            Unspecified = -1,

            D0 = 0, //Full power

            D1,

            D2,

            D3,

            D4, //Unpowered

        }

        private const int POWER_NAME = 1;

        private const int POWER_FORCE = 4096;

        private static string GetDeviceName()

        {

            //Get the device name from the registry

            string target = "";

            RegistryKey TheKey = Registry.LocalMachine.OpenSubKey("System\\CurrentControlSet\\Control\\Power\\State\\Suspend", false);

            if (TheKey != null)

            {

                string[] subkey = TheKey.GetSubKeyNames();

                target = subkey.GetValue(0).ToString();

                TheKey.Close()

            }

            RegistryKey rk = Registry.LocalMachine.OpenSubKey("System\\CurrentControlSet\\Control\\Power\\State");

            if (rk != null)

            {

                foreach (string items in rk.GetValueNames())

                {

                    if (items.Replace(target, "") != items)

                    {

                        rk.Close();

                        return items;

                    }

                }

                rk.Close();

            }

            return "";

        }

        public static bool IsEnabled()

        {

            //Checks if the WiFi is enabled or disabled

            try

            {

                int i = -1;

                if (iPAQGetWLANRadioStatus(ref i))

                {

                    if (i == 1)

                        return true;

                    else if (i == 0)

                        return false;

                }

            }

            catch { }

            string tmp = GetDeviceName();

            if (tmp.Length > 0)

            {

                DevicePowerState x = new DevicePowerState();

                GetDevicePower(tmp, POWER_NAME | POWER_FORCE, ref x);

                if (x == DevicePowerState.D0)

                    return true;

                else

                    return false;

            }

            return false;

        }

        public static void ToggleWifi()

        {

            //Enables/Disables the WiFi device

            //Default values -> Enable WiFi

            int NewI = 1;

            DevicePowerState DevP = DevicePowerState.D0;

            if (IsEnabled())

            {

                //WiFi is already enabled -> disable it

                NewI = 0;

                DevP = DevicePowerState.D4;

            }

            try

            {

                iPAQSetWLANRadio(ref NewI);

            }

            catch

            { }

            string tmp = GetDeviceName();

            if (tmp.Length > 0)

            {

                SetDevicePower(tmp, POWER_NAME | POWER_FORCE, DevP);

            }

        }

    }

}

My new blog

Welcome!
Yesterday I opened my own forum, today I'm starting my own blog.

I just wanted to do some Windows Mobile blogging which contains help for PocketPC developers. I know there are tons of blogs out there but if you're doing Windows Mobile programming it's so hard to find all the necessary information. For some problems I even needed months to find a solution...

So basically this is a collection of my collected and own knowledge about doing some deeper interaction with Windows Mobile...

Have fun with it! It will be filled soon!