C# Discussion Boards - CodeProject

29-Feb-04 23:13

Dear All,
I want to capture the keycode from keyboard buffer in VB.Net or C# Compact Framework.
Actually, I want to make a TSR(Terminate And Stay Resident) utility
which continuously look at the key strocks of keyboard and as soon as
a special key combination is pressed, it will invoke a function to
perform a series of actions.
For this purpose, I need to capture the keycode at system level not at
form level. So, how can i get keycode from keyboard buffer directly?
Tell me about some API for this purpose.

Regards,

Muhammad Arif

Mazdak29-Feb-04 23:23

29-Feb-04 23:23

http://www.codeproject.com/csharp/NetWin32Hooks.asp[^]

Mazy

"A bank is a place that will lend you money if you can prove that you don't need it." - Bob Hope

aliarifpk29-Feb-04 23:37

29-Feb-04 23:37

Dear Mazy,
There are two issues in the link you provided
1- This is for .NET Framework not for .NET Compact Framework
2- This code is for Mouse hooking not for keyboard
Please reply me for the code related to keyboard and written in .net compact framework.

Regards,

Muhammad Arif

Mazdak29-Feb-04 23:40

29-Feb-04 23:40

aliarifpk wrote:
1- This is for .NET Framework not for .NET Compact Framework

Oh,sorry for that I didn't take attention to it.

aliarifpk wrote:
2- This code is for Mouse hooking not for keyboard

They follow the same procedure, you can find out yourself when you learn one.

Mazy

"A bank is a place that will lend you money if you can prove that you don't need it." - Bob Hope

aliarifpk29-Feb-04 23:46

29-Feb-04 23:46

Dear Mazy,
I am working on this task for last three days and the API's in .Net Framwork doesn't supported in .Net Compact Framework. That's why I am looking for some alternated which read the keyboard buffer and yet searching .... If someone has done this ... please let me know

Regards,

Muhammad Arif

Dave Kreskowiak1-Mar-04 6:53

Dave Kreskowiak

1-Mar-04 6:53

Windows CE doesn't support message hooks. Hooking the keyboard isn't possible like it is under Windows 9x/2000/XP/2003.

RageInTheMachine9532

aliarifpk1-Mar-04 20:38

1-Mar-04 20:38

Dear Dave,
Can you provide me some authenticated URL which agree with your argument that Windows CE doesn't support hooking? I have to have a proof to my client for this argument.

Arif

Muhammad Arif

Dave Kreskowiak2-Mar-04 4:16

Dave Kreskowiak

2-Mar-04 4:16

More of the proof is going to be in what you DON'T find. But, here is a mention of it on MSDN:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceui40/html/ceconEventHandling.asp[^]

and at the bottom of this page:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceui/htm/_wcesdk_Receiving_and_Dispatching_Messages.asp[^]

Also, you won't find SetWindowsHook, or anything like it, in the Windows CE API Reference.
This functionality was left out because of performance issues and just because these hooks would not be used very much on small devices.

RageInTheMachine9532

Mazdak29-Feb-04 23:42

UserControl in VisualBasic 6.0

29-Feb-04 23:42

aliarifpk wrote:
This is for .NET Framework not for .NET Compact Framework

I don't think it make difference cause you have to call win32 API as you can see in that article, so I think you can use those API there too.

Mazy

"A bank is a place that will lend you money if you can prove that you don't need it." - Bob Hope

god4k29-Feb-04 20:29

god4k

29-Feb-04 20:29

UserControl in VisualBasic 6.0 has
UserControl_AsyncReadComplete(AsyncProp As AsyncProperty) Event,
UserControl_AsyncReadProgress(AsyncProp As AsyncProperty) Event and
UserControl.AsyncRead() Method

To create in C#, I should use what class?

Note: The event and method I mention is very excellent, No side effect while downloading

Sorry for bad English.
Thank You.

Re: UserControl in VisualBasic 6.0

Mazdak29-Feb-04 21:00

Inserting thread in single process

29-Feb-04 21:00

What do you want to exactly do? and what is that UserControl? Those are Async. methods and in your class you don'm implement them, you just call them in your client like that.

Mazy

"A bank is a place that will lend you money if you can prove that you don't need it." - Bob Hope

azusakt29-Feb-04 20:26

azusakt

29-Feb-04 20:26

hi,

I have some questions about making thread in my application, as I have no much experiences on Threading. Hope someone can help me.
In my application, I have a button function for outputing files. However, I need to generate some files and pictures before final step, the flow is simply like :

<br />
   private void menuItem4_Click(object sender, System.EventArgs e)<br />
   {<br />
      ....<br />
      Main_generate_process();<br />
     <br />
      finalStep();			<br />
   }<br />

The main problem is that before runing finalstep, I have to wait until the successful of Main_generate_process(), but I can't measure how long will the process take because the process is run in other DLL function, so I have an idea to use thread.

<br />
   private void menuItem4_Click(object sender, System.EventArgs e)<br />
   {<br />
      ....<br />
      //Start the background thread<br />
      outThread = new Thread(new ThreadStart(ThreadProc));<br />
      outThread.IsBackground = true;<br />
      outThread.Start();<br />
<br />
      do<br />
      { <br />
	<br />
      }while(this.outThread !=null);<br />
      <br />
        <br />
      finalStep();			<br />
   }<br />
<br />
   public void ThreadProc()<br />
   { <br />
     Main_generate_process();<br />
     StopThread();    <br />
   }<br />
<br />
   private void StopThread()<br />
   {<br />
	if (this.outThread != null)<br />
	{<br />
	outThread.Interrupt();<br />
	outThread = null;<br />
	}<br />
   }<br />

I found that the do-while loop also waste many times. Am I get a wrong idea?

The other quetion is :
can I call ThreadProc() directly in other function; i.e. if the thread has already started, and I need to run generate process again.

Thanks for help~~

Stefan Troschuetz29-Feb-04 21:27

Stefan Troschuetz

29-Feb-04 21:27

The method Thread.Join() should exactly fit to your requirements. See MSDN for further information. Your code should look like that:

private void menuItem4_Click(object sender, System.EventArgs e)
{
....
//Start the background thread
outThread = new Thread(new ThreadStart(ThreadProc));
outThread.IsBackground = true;
outThread.Start();
outThread.Join();
}

public void ThreadProc()
{
Main_generate_process();
}

azusakt29-Feb-04 22:55

azusakt

29-Feb-04 22:55

Thank you Troschi,

I have read and tried outThread.Join instead of using do-while loop, but Thread.Join() takes similar effect of do-while loop, it holds the main UI process, means caused the application in idle state.

I would like to run the process smoothly on background. so I need another good methods..

Stefan Troschuetz29-Feb-04 23:20

Stefan Troschuetz

29-Feb-04 23:20

Maybe this could help you. It's not that elegant but it should work.

outThread.Start();
while (outThread.ThreadState != ThreadState.Terminated)
{
Application.DoEvents();
}
DoEvents-method will process all Windows messages currently in the message queue, so your application should not be idle.

Other solution could be raising an event before the outThread terminates.

azusakt2-Mar-04 14:33

azusakt

2-Mar-04 14:33

THanks so much Troschi,

The code worked well, and the process does not held.
But will this method cause any hidden side effect?

I changed the code to :

outThread.Start();
while (outThread != null)
{
Application.DoEvents();
}

because I will call stopThread after processed the Thread function.

Stefan Troschuetz3-Mar-04 4:22

Stefan Troschuetz

3-Mar-04 4:22

You should consider what Tom Larsen mentioned in his comments. Any use of multi threading could turn into a debugging nightmare. So I recommend you disable your menuitem while running the event handler, to prevent the user from starting it again before it finishes execution.

scadaguy1-Mar-04 2:52

scadaguy

1-Mar-04 2:52

Try something like the following. I didn't test this so it may require some minor modifications.

private delegate void MyCallbackDelegate();

private void menuItem4_Click(object sender, System.EventArgs e)
{
  // Start the thread.
  outThread = new Thread(new ThreadStart(this.ThreadProc));
  outThread.IsBackground = true;
  outThread.Start();


  // Do not block the UI thread by placing a while loop
  // or Join() here.
}

private void ThreadProc()
{ 
  Main_generate_process();
  
  // Now we need to inform the UI thread that we are done.
  // We do this by executing a method on the UI thread.
  this.Invoke(new MyCallbackDelegate(this.InformUI)); 
}

private void InformUI()
{
  // We can safely access form controls because we are 
  // executing on the UI thread.
}

Tom Larsen1-Mar-04 4:23

Tom Larsen

1-Mar-04 4:23

The first thing you need to do is "join" the child process on the parent process. Doing this will insure that the parent will not proceed until the child processes have completed and therefore will call finalStep() at the right time.

The rest of the code snippet is unnecessarily complex. Just doing Thread.Join onto the parent thread should be more than enough syncronization. Threading topics like this can easily turn a simple task into a debugging nightmare. I would suggest you step back and read up on threading and the threading framework in .Net/C#.

scadaguy1-Mar-04 4:58

scadaguy

1-Mar-04 4:58

I would avoid the use of Thread.Join in the UI thread because it is a blocking call. The UI thread will be unable to process messages during the execution of the worker thread. The whole reason for using a thread in the first place is keep the UI thread active.