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Thank you David,
the reason I need to use DeviceIoControl is to catch the UART framing error that happens when I receive a DMX512 data packet.
I use the SerialPort class in trasmission without problem because I can create a correct DMX data packet with the starting break (line low - zero - at least for 88 µs) but when I receive data I can't get the break that starts the packet, I just get one zero, it doesn't metter how long the break is, but this break causes a framing error, so, if I get the framing error I get the start of the data packet.
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Yes, I tried to use the ErrorReceived event but it doesn't seem to work.
I use the DataReceived event to receive data and it works but I get no error, on the other hand I read in the help that:
...
PinChanged, DataReceived, and ErrorReceived events may be called out of order, and there may be a slight delay between when the underlying stream reports the error and when code can when the event handler is executed. Only one event handler can execute at a time.
...
However, I found another way using API and p/invoke: I use the function WaitCommEvent() to get directly the break instaed of the framing error.
This solution was suggested by Bruce Eitman in the MSDN Windows Embedded Compact forum and I found a good example in the article "Smart Device Print Engine for Compact Framework" by Orkun GEDiK here in CodeProject.
Thanks anyway for your interest and for your time.
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How to use keypress event inside timer?
i have to use
Asc(e.keypress)=102 '102-Ascii value of "f"
e.handled=true 'stop the key from processing
all these has to be done even when the application is minimized
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What you want is not possible.
First, the keypress event is raised on the UI-thread. Whatever timer is being used, it will not be raised during the timer-event. You'd need to buffer them keys somewhere.
If the application is minimized, then no keypress-events will be generated - since your app does not have input-focus. You'd need a keylogger for what you'd want - which brings us back to your previous question.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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I have a keylogger and it is detecting the key pressed.
but i want that the pressed key should not be processed to display on the screen what ever be the current application.
And How to have input-focus to my application.
Help me to solve these problems.......
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You're NOT going to use the normal form events for this, nor a timer.
You have to use a (Google for this "global keyboard hook".
Since you just admitted to making a keylogger, you're on your own from now on.
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Guys my aim is not to make a keylogger,i have to detect the ascii key pressed and block that keys from displaying and send my own characters to display.
But This keylogger detects only the key not the character.
with my minimized form i have to detect the ascii characters.How to do this?
I will explain What the exact process is to be done...
When I press any character in any editor the corresponding character should not be displayed on the screen(in other words Input Blocker) and instead of the blocked character i would like to disply my own characters.
i have to do this with my minimized form i.e when my form is in background and when it is closed the inputs should be displayed on the screen as i type.
help me guys plzzzzzzzz...............
modified 29-Oct-13 13:23pm.
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I already told you. If you're writing a keylogger, you're on your own.
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I am not writing a keylogger.Leave this keylogger topic.
I am asking help how to do the below process,help me for this......
When I press any character in any editor the corresponding character should not be displayed on the screen(in other words Input Blocker) and instead of the blocked character i would like to display my own characters in that editor.
i have to do this with my minimized form i.e when my form is in background and when it is closed the inputs should be displayed on the screen as i type.
How to do this process?
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how to place a number or a string in the registry.
and read that value from that place.
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Working with Windows Registry using VB.NET[^] - Sorry- Seems like someone else already pointed you there.
MSDN[^]
People becoming wiser in order to notice the stupid things they did back in the young days. This doesn't mean that they really stop doing those things. Wise people still do stupid things, only on purpose.
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I have Filewatcher services and after 300 files I am getting this error:
Too many changes at once in directory
how can I fix it?
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Try and put in meaningful filters in your file watcher code.
If you are monitoring every change, then you are going to run out of resources very quickly.
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i do have filtering however one a month we have a job which produce more then 300 files...
my filtering...
e.FullPath.ToUpper.IndexOf("~WRD") > -1 OrElse e.FullPath.ToUpper.IndexOf(".TMP")
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In that case you have to enlarge InternalBufferSize. It's default size is 4096 (4K). You must take your number of files to proceed (plus some) and multiply it by 16 (the size of each entry in the buffer); round it up to the next 1024 (1K) and set InternalBufferSize to it...
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is (V).
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Guys i would like to design a application that disables the keyboard.
when my application is opened or minimised the keyboard should not work and when i close it the keyboard should work as usually.How to do this?
Help Me Guys.........
PlZZZZ....
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Google for "global keyboard hook vb.net". All you do is not pass the key messgae to the next hook handler to disable the keyboare.
By the way, this does NOT work for disabling Ctrl-Alt-Del.
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I guess something like this piece of code[^] is what you want.
People becoming wiser in order to notice the stupid things they did back in the young days. This doesn't mean that they really stop doing those things. Wise people still do stupid things, only on purpose.
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Your piece of code is good And it works too but how to detect all the ascii values using this code........
For Example
How to detect Small "a",colon,braces etc.
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You have to change the following function:
Private Function HookCallback(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
If nCode >= 0 AndAlso (wParam.ToInt32 = WM_KEYUP OrElse wParam.ToInt32 = WM_SYSKEYUP) Then
Dim vkCode As Integer = Marshal.ReadInt32(lParam)
If vkCode = Keys.PrintScreen Then
Dim data As IDataObject = Clipboard.GetDataObject()
If data.GetDataPresent(GetType(Bitmap)) Then
Me.BackgroundImage = DirectCast(data.GetData(GetType(Bitmap)), Bitmap)
End If
End If
End If
Return CallNextHookEx(hookID, nCode, wParam, lParam)
End Function
instead of "If vkCode == Keys.PrintScreen Then"... you have to check wether your application is active, and forward the pressed key to it.
People becoming wiser in order to notice the stupid things they did back in the young days. This doesn't mean that they really stop doing those things. Wise people still do stupid things, only on purpose.
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I dont know How to declare functions that reads ascii characters..........
can you give me example to find small "a".
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srinivasankrishnaa wrote: how to detect all the ascii values using this code.
Since you're repeating the question, I'll repeat the answer[^].
There's not a unique key for each character available; you'd need a keyboard with 255 keys if each character would need a unique key. There's no separate key for "A" and "a". You can map a virtual key to a character using below function;
[DllImport("user32.dll", CharSet=CharSet.Auto)]
internal static extern int MapVirtualKey(int uCode, int uMapType);
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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