I need to tap default printer change notification, is it possible?
My scenario is that I want to execute a command whenever default printer is changed in window. What my command does is, it just takes default printer information from registry and save it in HKLM.
So, I have a service for this. Using this service, how can i tap notifications whenever a default printer is changed. I am using C++.
From a regular application, I would listen for a WM_SETTINGCHANGE message and then call GetDefaultPrinter to see if the default printer has actually changed.
I don't know if you can watch for that message from a service. The default printer can be a per-user setting, so your service would have to be running as that user rather than as Local System.
Intercept message WM_WININICHANGE, then get the new printer:
PRINTDLGW *pd;
pd = (PRINTDLGW *)malloc(sizeof(PRINTDLGW));
pd->lStructSize = sizeof(PRINTDLGW);
pd->hDevMode = NULL;
pd->hDevNames = NULL;
pd->Flags = PD_RETURNDEFAULT;
PrintDlgW(pd);
Related
Hey, I am trying to get a service to start my program but it isn't showing the GUI. The process starts but nothing is shown. I have tried enabling 'Allow service to interact with desktop' but that still isn't working.
My program is a computer locking device to stop unauthorised users from accessing the computer. I am running windows 7 with a 64 bit OS.
Here is the code for my service:
protected override void OnStart(string[] args)
{
Process p = new Process();
p.StartInfo.FileName = "notepad.exe";
p.Start();
FileStream fs = new FileStream(#"C:\Users\David\Documents\Visual Studio 2010\Projects\LockPCService\LockPCService\bin\Debug\ServiceLog.dj",
FileMode.OpenOrCreate, FileAccess.Write);
StreamWriter m_streamWriter = new StreamWriter(fs);
m_streamWriter.BaseStream.Seek(0, SeekOrigin.End);
m_streamWriter.WriteLine(" LockPCService: Service Started " + DateTime.Now + "\n" + "\n");
m_streamWriter.Flush();
m_streamWriter.Close();
}
protected override void OnStop()
{
FileStream fs = new FileStream(#"C:\Users\David\Documents\Visual Studio 2010\Projects\LockPCService\LockPCService\bin\Debug\ServiceLog.dj",
FileMode.OpenOrCreate, FileAccess.Write);
StreamWriter m_streamWriter = new StreamWriter(fs);
m_streamWriter.BaseStream.Seek(0, SeekOrigin.End);
m_streamWriter.WriteLine(" LockPCService: Service Stopped " + DateTime.Now + "\n"); m_streamWriter.Flush();
m_streamWriter.Close();
}
To try and get the service working I am using notepad.exe. When I look at the processes notepad is running but there is no GUI. Also the ServiceLog is there and working each time I run it.
Any ideas on why this isn't working?
Thanks.
This article explains Session 0 Isolation which among other things disallows services from creating a UI in Windows Vista/7. In your service starts another process, it starts in Session 0 and also will not show any UI. (By the way, the UI is created, it's just that Session 0 is never displayed). This article on CodeProject can help you create a process from a service on the user's desktop and show its UI.
Also, please consider wrapping you stream objects in a using statement so that they are properly disposed.
Services run under different account so notepad is run by another user and on another desktop so that's why you cannot see it. 'Allow service to interact with desktop' is not supported anymore starting from Vista.
I know this is a late post, but I found that this article was very helpful to me. I am running Windows 7 and the solution provided in this article works great.
If you download the code, there is a class called ApplicationLoader. Include that class in your project and then it's as simple as this:
// the name of the application to launch
String applicationName = "cmd.exe";
// launch the application
ApplicationLoader.PROCESS_INFORMATION procInfo;
ApplicationLoader.StartProcessAndBypassUAC(applicationName, out procInfo);
Services run in a different logon session and have a different window station from the user. That means that all GUI activity is segregated from the user's programs, not that the service can't display a GUI. Actually, this design makes it much easier to temporarily block access to the user's programs.
You'll need to call SwitchDesktop.
edit: My issue was never quite resolved, but the answer below provided an interesting result.
The app will eventually be called by a powershell script and in this situation, I don't have the issue explained below. No additional {ENTER} is required in the PS console, so no more issue! I couldn't care less if an extra ENTER is required when my app is launched manually via cmd.exe
Problem: In a VB.NET
form app, I'm unable to get the console back to it's "default" state after the code is finished running. I need to press enter manually.
My app can also be executed from command line (in this case, no form is opened. Code is being executed automatically and output sent to console for user to see what happens)
I call AttachConsole(-1), run some code, and when everything's finished I see my latest message in console, but it's as if the process wasn't quite finished.
I have tried SendKeys.SendWait("{ENTER}"). It works well, but only when the console is the current focus. If I click outside the console while the code is running, the ENTER key is sent to whichever window I made active.
So I tried to make the console the current window:
Dim bProcess As Process = Process.GetProcessesByName("cmd").FirstOrDefault()
SetForegroundWindow(bProcess.MainWindowHandle)
// I also tried AppActivate(bProcess.Id)
SendKeys.SendWait("{ENTER}")
FreeConsole()
Nope, the ENTER key will still be sent somewhere else and not to the console. But it does make the console blink orange, so SetForegroundWindow seems to do something...
Any help will be greatly appreciated :)
EDIT
In response to #TnTinMn's answer:
FreeConsole()
// SendKeys.SendWait("test")
PieceOfCodeFromTnTinMn()
Same behavior as I've had so far: This will send the SendKeys.SendWait("~")command "outside" the console if it loses focus while the code is running.
BUT with the 2nd line above un-commented, "test" is sent outside the console and SendKeys.SendWait("~") is sent to the console, as expected.
I'm still trying to figure out what is happening here...
You can use the VB Interaction.AppActivate Method to activate the parent console prior to calling SendKeys.SendWait. This requires that you obtain the ProcessID of the console window that is the parent process of your application.
One way to do this is using Windows Management Instrumentation (WMI). The following is not pretty, but it appears to work. You would execute this after calling FreeConsole
Using currentProcess As Process = Process.GetCurrentProcess
Dim query As New SelectQuery()
Dim props As New StringCollection
props.Add("ProcessId")
props.Add("ParentProcessId")
With query
.ClassName = "Win32_Process"
.Condition = $"ProcessId={currentProcess.Id}"
.SelectedProperties = props
End With
Dim parentProcessId As Int32
Using searcher As New ManagementObjectSearcher(query)
Using mos As ManagementObjectCollection = searcher.Get
Using en As ManagementObjectCollection.ManagementObjectEnumerator = mos.GetEnumerator
If en.MoveNext() Then
parentProcessId = CInt(en.Current.Item("ParentProcessId"))
End If
End Using 'en
End Using ' mos
End Using 'searcher
If parentProcessId <> 0 Then
AppActivate(parentProcessId)
SendKeys.SendWait("~")
End If
End Using 'currentProcess
I can not find how to start WPS client in Windows 10 from command prompt or powershell. When I used Linux, everything was really ease with wla_supplicant (wpa_cli wps_pbc). Is there something similar in Windows?
Does anyone know how to set up Wi-Fi network (over WPS) key without human input in Windows?
I also tried WCN (Windows Connect Now) from Microsoft as it implements WPS features. I got also samples from Windows SDK on WCN, but they could not get key by WPS (it faild). But if I use Windows user interface to connect wiothout PIN, everyting seems to be pretty fine.
I am sure that there is possibility to do that, it is very important to perform Wifi Protected Setup by button start from the command prompt or app (C++/C#) without human intrusion or input (once WPS is on air, Windows should automatically get the network key and connect then).
I don't know if it's too late to answer, just put what I know in here and hope it can help.
First, if your system has updated to 16299(Fall Creator Update), you can just simply use new wifi api from UWP.
Install newest Windows SDK, create a C# console project, target C# version to at least 7.1, then add two reference to the project.
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETCore\v4.5\System.Runtime.WindowsRuntime.dll
C:\Program Files (x86)\Windows Kits\10\UnionMetadata\10.0.16299.0\Windows.winmd
After all of that , code in below should work.
using System;
using System.Threading.Tasks;
using Windows.Devices.Enumeration;
using Windows.Devices.WiFi;
class Program
{
static async Task Main(string[] args)
{
var dic = await DeviceInformation.FindAllAsync(WiFiAdapter.GetDeviceSelector());
if (dic.Count > 0)
{
var adapter = await WiFiAdapter.FromIdAsync(dic[0].Id);
foreach (var an in adapter.NetworkReport.AvailableNetworks)
{
if (an.Ssid == "Ssid which you want to connect to.")
{
// Fouth parameter which is ssid can not be set to null even if we provided
// first one, or an exception will be thrown.
await adapter.ConnectAsync(an, WiFiReconnectionKind.Manual, null, "",
WiFiConnectionMethod.WpsPushButton);
}
}
}
}
}
Build and run the exe, then push your router's button, your pc will be connect to the router.
But if you can not update to 16299, WCN will be your only choice. You may already notice that if call IWCNDevic::Connect frist with push-button method, the WSC(Wifi Simple Configuration) session will fail. That's because WNC would not start a push-button session as a enrollee, but only as a registrar. That means you have to ensure that router's button has been pushed before you call IWCNDevic::Connect. The way to do that is using Native Wifi api to scan your router repeatedly, analyse the newest WSC information element from the scan result, confirm that Selected Registrar attribute has been set to true and Device Password Id attribute has been set to 4. After that, query the IWCNDevice and call Connect function will succeed. Then you can call IWCNDevice::GetNetworkProfile to get a profile that can use to connect to the router. Because it's too much of code, I will only list the main wifi api that will be used.
WlanEnuminterfaces: Use to get a available wifi interface.
WlanRegisterNotification: Use to register a callback to handle scan an connect results.
WlanScan: Use to scan a specified wifi BSS.
WlanGetNetworkBsslist: Use to get newest BSS information after scan.
WlanSetProfile: Use to save profile for a BSS.
WlanConnect: Use to connect to a BSS.
And about the WSC information element and it's attributes, you can find all the information from Wi-Fi Simple Configuration Technical Specification v2.0.5.
For Krisz. About timeout.
You can't cast IAsyncOperation to Task directly. The right way to do that is using AsTask method. And also, you should cancel ConnectAsync after timeout.
Sample code:
var t = adapter.ConnectAsync(an, WiFiReconnectionKind.Manual, null, "",
WiFiConnectionMethod.WpsPushButton).AsTask();
if (!t.Wait(10000))
t.AsAsyncOperation().Cancel();
I know the Brew application have 3 types: active, suspend & background. Launch one BREW application as active or suspend is very simple. I know in BREW2.0 and later version, there is a new application type can allow we create one application in the background. It will not stay in the application stack and change status by active or resume command. It will always stay in the background no matter what user command system received. In one of my small project, I need to create and launch one background application like this.
Unfortunately, I cannot find a simple example on Qualcomm or Google. Is there any programmer who has encountered the same problem?
Yes, you are right. BREW2.0+ do support background application.
When we initial a background application, just like other normal new application, it can be launched by the brew application interface directly. You also can launch it by ISHELL_StartApplet function.
When you want to put one brew application in the background, you need do it when handle EVT_APP_STOP event and must set dwParam to false. After handling EVT_APP_STOP by this, the application will be put in the background. And if you want to change it to normal application, you need call ishell_StartApplet function to active to itself again.
Example code:
typedef struct _bgApp
{
AEEApplet a;
boolean m_bGoBg;
} bgApp;
switch (eCode)
{
case EVT_APP_START:
if(pMe->m_bGoBg)
ISHELL_CloseApplet(pMe->a.m_pIShell, FALSE);
case EVT_APP_STOP:
if(pMe->m_bGoBg)
*((boolean*) dwParam) = FALSE;
return TRUE;
case EVT_USER:
if(pMe->m_bGoBg)
{
pMe->m_bGoBg = FALSE;
// make applet active
ISHELL_StartApplet(pMe->a.m_pIShell, AEECLSID_BGAPP); }
else
{
pMe->m_bGoBg = TRUE;
// trigger EVT_APP_STOP to send app to background
ISHELL_CloseApplet(pMe->a.m_pIShell, FALSE);
}
return TRUE;
}
There is a limitation of background application. You cannot change the screen or communicate with user directly. Developer should be careful on the memory used by the background application. This is very important.
I'm trying to register my application that will handle opening of links, e,g, http://stackoverflow.com. I need to do this explicitly for Windows 8, I have itworking in earlier versions of Windows. According to MSDN this has changed in Win8.
I've been through the Default Programs page on MSDN (msdn.microsoft.com/en-us/library/cc144154.aspx) page on MSDN. It provides a great walkthrough on handling file types but is light on details for protocols. Registering an Application to a URL Protocol only goes over the steps involved in setting up a new protocol, but not how to correctly add a new handler to an existing protocol.
I've also tried the registry settings outlined in other SO posts.
One more thing, the application is not a Metro/Windows Store App, so adding an entry in the manifest won't work for me.
You were on the right track with the Default Programs web page - in fact, it's my reference for this post.
The following adapts their example:
First, you need a ProgID in HKLM\SOFTWARE\Classes that dictates how to handle any input given to it (yours may already exist):
HKLM\SOFTWARE\Classes
MyApp.ProtocolHandler //this is the ProgID, subkeys are its properties
(Default) = My Protocol //name of any type passed to this
DefaultIcon
(Default) = %ProgramFiles%\MyApp\MyApp.exe, 0 //for example
shell
open
command
(Default) = %ProgramFiles%\MyApp\MyApp.exe %1 //for example
Then fill the registry with DefaultProgram info inside a Capabilities key:
HKLM\SOFTWARE\MyApp
Capabilities
ApplicationDescription
URLAssociations
myprotocol = MyApp.ProtocolHandler //Associated with your ProgID
Finally, register your application's capabilities with DefaultPrograms:
HKLM\SOFTWARE
RegisteredApplications
MyApplication = HKLM\SOFTWARE\MyApp\Capabilities
Now all "myprotocol:" links should trigger %ProgramFiles%\MyApp\MyApp.exe %1.
Side note since this is a top answer found when googling this kind of an issue:
Make sure the path in the shell command open is a proper path to your application.
I spent an entire day debugging issue that seemed only to affect Chrome and Edge on Windows 10. They never triggered the protocol handler while Firefox did.
What was the issue? The path to the .bat file used mixed
\ and / slashes.
Using only proper \ slashes in the path made Edge & Chrome suddenly able to pick up the request.
LaunchUriAsync(Uri)
Starts the default app associated with the URI scheme name for the specified URI.
You can allow the user to specify, in this case.
http://msdn.microsoft.com/library/windows/apps/Hh701476
// Create the URI to launch from a string.
var uri = new Uri(uriToLaunch);
// Calulcate the position for the Open With dialog.
// An alternative to using the point is to set the rect of the UI element that triggered the launch.
Point openWithPosition = GetOpenWithPosition(LaunchUriOpenWithButton);
// Next, configure the Open With dialog.
// Here is where you choose the program.
var options = new Windows.System.LauncherOptions();
options.DisplayApplicationPicker = true;
options.UI.InvocationPoint = openWithPosition;
options.UI.PreferredPlacement = Windows.UI.Popups.Placement.Below;
// Launch the URI.
bool success = await Windows.System.Launcher.LaunchUriAsync(uri, options);
if (success)
{
// URI launched: uri.AbsoluteUri
}
else
{
// URI launch failed. uri.AbsoluteUri
}