i am creating a window service. my requirement is to display window form from window NT service on particular interval. For testing purpose , i just want to display the form on service start:
protected override void OnStart(string[] args)
{
eventLog1.WriteEntry("In OnStart -before form show");
Messager_Form obj = new Messager_Form();
obj.Show();
// System.Diagnostics.Process.Start("calc.exe");
eventLog1.WriteEntry("In OnStart -after form show");
// timer1.Start();
}
it not working. Neither form is showing nor calc process is running. i have found some links
showing pop up , but most of them suggesting WCF. isn't it possible without wcf. can anybody show me the way to achieve this.
Cant be done*. In later Operating Systems that won't work as Windows Services are disallowed from interacting with the Desktop - instead UI presented by Windows Services is shown in Session 0, a special logon session which is not normally visible to the end user.
What you should instead do is write a separate Windows Forms application which is always running, but not always visible (possibly have that application run at startup and have an icon in the notification area) and communicates with the Windows Service using some form of IPC
When the Windows Service wishes to display some UI to the user it sends a message to the application, which in turns shows the desired UI to the end user.
*or at least it definitely shouldn't be done
I am just referring to the answer given in another link in StackOverflow
How to communicate with a windows service from an application that interacts with the desktop?
Answer is :
Be aware that if you are planning to eventually deploy on Windows Vista or Windows Server 2008, many ways that this can be done today will not work. This is because of the introduction of a new security feature called "Session 0 Isolation".
Most windows services have been moved to run in Session 0 now in order to properly isolate them from the rest of the system. An extension of this is that the first user to login to the system no longer is placed in Session #0, they are placed in Session 1. And hence, the isolation will break code that does certain types of communication between services and desktop applications.
The best way to write code today that will work on Vista and Server 2008 going forward when doing communication between services and applications is to use a proper cross-process API like RPC, Named Pipes, etc. Do not use SendMessage/PostMessage as that will fail under Session 0 Isolation.
http://www.microsoft.com/whdc/system/vista/services.mspx
Now, given your requirements, you are going to be in a bit of a pickle. For the cross-platform concerns, I'm not sure if Remoting would be supported. You may have to drop down and go all the way back to sockets: http://msdn.microsoft.com/en-us/library/system.net.sockets.aspx
Checking the "Interact with desktop" box will work on Windows NT, 2000, XP and 2003 but thanks to Session 0 Isolation that setting no longer works as you may expect in Windows Vista and beyond. You want to think very carefully before developing an interactive service...
Related
I need to display Message Box and Windows Forms through windows service by using c#. Anyone Please help me. Thanks in advance.
You cannot (easily) do this directly from the service's process. As descibed here, there is a way to create an interactive service, that is able to send/process windows messages and display windows.
But: Since Windows Vista, all services run in a separate user session, named "session 0". Thus, all windows displayed by services, are displayed in that session. It is theoretically possible (I have even done that once, just for fun), to switch to this session and view these windows, but this would hardly be of use in real life.
My advice would be to create a separate gui application (maybe one with a nice tray icon), that communicates with your service via e.g. TCP/IP or a database. This application can then handle any required user interaction and do the appropriate interaction with the service's process.
I have created a windows Form tray application in C# .NET 4.0 that does some random things, not important, for Windows XP SP3.
The intention is that the application is to be started using Windows Services and should be running as LocalSystem with "Allow service to interact with desktop" checked. I understand the security implications and that services are not meant to be running GUI's etc, but this is the point of the program and is being used for training purposes.
When I start the application using the Services.msc utility it starts fine, but after about 10 seconds it states "Error 1053: The service did not respond to the start or control request in a timely fashion"
I have looked at a number of other solutions without any luck, for example:
https://social.msdn.microsoft.com/Forums/vstudio/en-US/dac443c1-f2fc-49c6-bdd4-5426edc946ee/how-to-start-calcexe-from-windows-service-
I don't really care about a nice programming example. I can either create a service then have the tray application called API's, but I don't know if the tray application will run with elevated privs, or create a forms application and hack it to run as a Windows XP service or get a proper service to launch an exe being my tray application...
Any examples would be much appreciated or links to coding examples etc.
For a windows service, if your overridden OnStart method performs a lot of work, you will get the "Error 1053: The service did not respond to the start or control request in a timely fashion" error.
You can call the ServiceBase.RequestAdditionalTime method with enough time required to perform whatever work is needed.
See http://msdn.microsoft.com/en-us/library/system.serviceprocess.servicebase.requestadditionaltime%28v=vs.110%29.aspx for refrence.
Just in case this happens to someone else. I just used the Windows 2003 Resource kit and used 'SRVANY'.
More information is available here:
http://support.microsoft.com/kb/137890
and here:
http://www.tacktech.com/display.cfm?ttid=197
I just followed the instructions except for ticking the checkbox in Services "Allow Service to Interact with Desktop"
Thanks for the Answer Dietz, it is probably the correct way in getting it working but this is just a simple hack.
I want to load a form in OnStart() method in my windows service; here is my code. It is not working. Can you please provide any help ?
protected override void OnStart(string[] args)
{
Form1 fr = new Form1();
fr.Show();
}
You can't use services that way. Services can't interact with desktop directly, because they run in another WindowsStation from the logged in users session. You need to create another application that will communicate with your service.
How to make communication you can read on MSDN and in this example. Some ideas also described already on StackOverflow.
Services run in a different window station and desktop to any interactive user. Even if the form is loaded successfully nobody will be able to see it.
You can set the "Allow service to interact with desktop" service option which allows a service to share the console's window station. However, this is a really bad idea. It opens up security holes and a host of other problems. E.g. what happens if there is more than one user logged in? Or if you're running terminal services?
A more conventional design is to have a client application handling the UI and talking to the service running in the background.
GUI requires Single-Threaded Apartment threading model. Forms require a message pump (like the one started by Application.Run).
A service is definitely not designed to show GUI (even interactive services are considered bad practice), it can be controlled from a GUI, though.
For a service to display a window it has to be marked as "Allow interaction with desktop". This can be done by the service installer or on the property page for that service.
That's not enough to get the window to display reliably, though. In practice you will have to determine if there is a user currently logged in and get their desktop. This is not a trivial undertaking and can be a source of security issues. If there is no one currently logged in, you are out of luck.
The best solution is to have a separate GUI app which talks to the service via some IPC mechanism.
I have an application, written by me in C#.net 2.0 - when the application is opened, a timer will check every 3 seconds for x. If x happens, it shows a warning in a windows form.
Is there a possibility to install this timer and the windows form call in a windows-service? So that the timer ticks every time a system is up and shows the message then?
No, it is not possible to have a service display a form. This is by design, since a service is supposed to run without a user interface
You can have a regular application that communicates with your service and displays the warning, but I don't know how exactly this is done.
IMO, you don't need a service, just create a regular application without a main form that runs in the background, performs your check, and displays a warning when necessary. You can add that application to the Run section of HKLM or HKCU, so that it is always started when a user logs on to the system.
Windows Forms cannot be displayed from a Windows Service. A Service runs only in the background.
You can have a separate Windows application that communicates with the Windows service and display warnings, information, etc.
To do this, the service runs on the LocalSystem account, and you have to enable the property for the service to interact with the desktop.
Services are forbidden from interacting with the desktop, including displaying windows or forms. In windows 2003 and XP you could work around the issue by marking the service 'interactive' and this would allow the service to display on the user session, but as of Windows 2008 and Vista this is enforced and services can no longer interact in any fashion with the user.
When services need to display anything, the solution is to split the logic into two separate processes, one being the service and one being a normal user process. The user process runs launched by the user, in its session (it can be launched automatically at session start up) and it connects to the service via some IPC channel (shared memory, named pipes, sockets etc). The service can then display anything it wishes to the user by asking the user process half of the application to display what it needs to display.
As others have said, remember that a windows service is supposed to be a background, never-interacting-with-the-user program. Many services run even when the user is not logged on -- how would they go about displaying a form when there's no desktop for them to display it on?
That said, it shounds like you're trying to shoehorn something into a service that shouldn't be a service. If you want something that runs in the background and still interacts with the user, look into making a lightweight system try application. In fact... here's a helpful tutorial:
Lightweight System Tray Application (NotifyIcon Based)
We have to run a process from a windows service and get a screenshot from it.
We tried the BitBlt and PrintWindow Win32 calls, but both give blank (black) bitmaps.
If we run our code from a normal user process, it works just fine.
Is this something that is even possible? Or could there be another method to try?
Things we tried:
Windows service running as Local System, runs process as Local System -> screenshot fails
Windows service running as Administrator, runs process as Administrator -> screenshot fails.
Windows application running as user XYZ, runs a process as XYZ -> screenshot works with both BitBlt or PrintWindow.
Tried checking "Allow service to interact with desktop" from Local System
We also noticed that PrintWindow works better for our case, it works if the window is behind another window.
For other requirements, both the parent and child processes must be under the same user. We can't really use impersonation from one process to another.
Currently i can't find the corresponding links, but the problem is, that a windows service runs in another session than a normal user application.
In XP this was not fully true. Here are all services started in Session 0 and the first user who logs into the system will also run in Session 0. So in that case, tricks like Allow service to interact with desktop work. But if you fast switch to another user he gets the Session 1 and has no chance to interact with the service directly. This is also true if you connect through RDP to a server version (like 2003 or 2008). These logins will also start in a session higher than 0.
Last but not least there is another drawback by using the interaction with the desktop:
If you enable this option and your service is running under the (default) SYSTEM account it won't be able to create a network connection anymore.
The correct way to get a custom GUI that works with a service is to separate them into two processes and do some kind of IPC (inter process communication). So the service will startup when the machine comes up and a GUI application will be started in the user session. In that case the GUI can create a screenshot, send it to the service and the service can do with it, whatever you like.
Have you tried to run as Local System with the "Allow service to interact with desktop" checked?
I don't think this is possible.
We had to change our scenario where our application wasn't started from a service, but was a standard windows program that has a NotifyIcon in the corner.
If someone still finds a real answer, let me know.
It works using Local System with the "Allow service to interact with desktop"
You can set it programatically using this sample code:
http://www.vbforums.com/showthread.php?t=367177 (it's vb.net but very simple)