|
Hi,
What would be the fastest way to ping 255 IP addresses?
Are there any example with using multithreading, as I am quite new to threading.
|
|
|
|
|
The multi-threading itself isn't problematic; getting it all done in a reasonable time may be a bit of a problem.
I would use say four to eight identical instances of a class that starts a thread which, in a loop:
- fetches an IP address out of a shared queue;
- calls Network.Ping();
- stuffs the result in another shared queue.
Of course, both queues need their lock.
You should not pre-assign IP addresses to threads, as you can't predict how long a ping operation will take; typically those that succeed run fast, and the failing ones have to wait for their time-out. And adding more threads won't help much as I expect you will end up running in network limitations.
|
|
|
|
|
For my application I can set time-out to less then 250ms, so waiting is not a issue.
When using lock, does this mean the first thread that access "variable" locks the access and
if other threads are trying to access same "variable" wait (like thread.sleep) until it is released?
|
|
|
|
|
1.
250msec * 255 IP adr / 8 threads is still 8 seconds.
2.
yes, said locks would be exclusive, but only while accessing the queue, not while pinging (hence only a small fraction of the time). Like so (in pseudo-code!):
lock(IPadrLock) {
IPadr=IPadrQueue.Dequeue();
}
result=ping(IPadr);
lock(resultLock) {
resultQueue.Enqueue(result);
}
|
|
|
|
|
|
It is polite to up vote a helpful answer.
Never underestimate the power of human stupidity
RAH
|
|
|
|
|
Hey Guys
In our company we switched from Office 2000 to 2010 a couple of days ago. Now we have a very strange Problem. About 6 different applications could create Word reports (data sheets for heat plate exchangers) under Office 2000. Now under 2010 sometimes we can generate the Word report (on the first start after logon), then after the 2nd or 3rd it no longer works, Word opens but the document is blank. The error we see in those applications is "OLE Automation ERROR".
To trace the problem i wrote the following c# application:
_Application wordApplication = new Microsoft.Office.Interop.Word.Application();
var f = new FileInfo(txtPath.Text);
object o_null = Missing.Value;
object o_true = "";
object o_false = "";
object o_filePath = @"" + f.FullName;
Document doc = wordApplication.Documents.Open(ref o_filePath, ref o_null, ref o_null, ref o_null, ref o_null, ref o_null, ref o_null, ref o_null, ref o_null, ref o_null, ref o_null, ref o_null);
String text = doc.Content.Text;
Thats the relevant part of the code, there is just some gui-code more, nothing special. Of course the Microsoft.Office.Interop.Word-Com object is referenced.
On the first launch of this programm, reading the content of a word document works perfectly. The second time i hit the open-document button in this c#-app i get the following error:
System.Runtime.InteropServices.COMException (0x800A1066): Command failed
at Microsoft.Office.Interop.Word.Documents.Open(Object& FileName, Object& ConfirmConversions, Object& ReadOnly, Object& AddToRecentFiles, Object& PasswordDocument, Object& PasswordTemplate, Object& Revert, Object& WritePasswordDocument, Object& WritePasswordTemplate, Object& Format, Object& Encoding, Object& Visible, Object& OpenAndRepair, Object& DocumentDirection, Object& NoEncodingDialog, Object& XMLTransform)
To solve this Problem i tried almost everything:
Different users (all with local admin accounts)
Different computers (newly installed windows xp sp3)
reinstalled Office 2010 /repaired Office 2010
New domain user accounts
Changed the access rights in DCOM-Word-Object to local administrator
The weird thing is, after logging in the first time, generating one word report works, then the second time it sometimes works but on the third or fourth and so on time we get the error above.
I know, this problem lies probably more in the windows system and not the actual c# application (the other applications aren't written in c# but show the same behaviour), but i thought maybe someone of you could have an idea.
I would be really happy if anybody could help me solving this problem. It don't know anything more I could do!
regards from switzerland
Urs
modified on Tuesday, November 9, 2010 9:14 AM
|
|
|
|
|
Hi,
I haven't done these things myself, however I remember reading about it. Here are some thoughts:
1.
different versions of Office need different libraries ("Primary Interop Adapters"), so you would have to rebuild your app, and you can make it work reliably with only one Office version at a time. I suggest you google for details.
2.
Most articles don't discuss handling multiple Word documents; and most do close both the document and the Word application (your shortened example did not show that).
3.
Here is one CodeProject article on Office automation out of many: Word Automation using VB.NET - Part I[^]
Hope this helps.
|
|
|
|
|
Hey Luc
Thank you very much for your quick answer.
Ok so I downloaded the project from step 3.
I hit the open-doc Button: Document gets opened in MS Word
I hit the read word button: Msgbox appears with document content
I hit the read word button again: Again the msgbox appears with document content
I hit the read word button for the 3rd time: Msgbox appears with document content
I hit the open-doc Button: unhandled Exception System.Runtime.InteropServices.COMException (0x800A1066): command failed
Now the buttons don't work anymore. no open or read...
I closed the app. opened it again. first time opening the word doc works, 2nd and 3rd try no more...
I closed the app again. reopened it. again the first time was ok, any further clicks on open-doc will result in the same Exception above
There is something wrong, but I don't have a clue what...
|
|
|
|
|
That sounds weird. Some more thoughts:
1. you could try on another machine, maybe something is wrong with your Office.
2. if still no luck, you could post on that article's forum too.
3. are you doing anything special within Word? macro's? VBA code?
|
|
|
|
|
Yes it is really weird indeed.
Tried already different machines. On one i'm doing a clean reinstall right now and then i'm going to check again.
No we do not use features like macros or vba.
|
|
|
|
|
Office 2010 does not support automation from unattended client application or components. Maybe this link[^] can help you.
|
|
|
|
|
Hmm thanks for the link.
So with office 2010 the "remote controll" for word via interop-services is gone?
Its weird, because why should it work the first time i do an export and then it doesn't go any further. and our vendor has other customers working with office 2010 and they don't have the problem.
Has anybody for example tested this project demo here with office 2010:
Word Automation using VB.NET - Part I[^]
|
|
|
|
|
Well, not exactly that, I think. What Microsoft says is that it is gone for unattended client applications. What I understand here is that an Office Application might, for example, show a MessageBox, which requires user interaction, and thus an unattended client application would not be able to handle it and any further request to the Office application will unavoidably lead to a COMException.
|
|
|
|
|
Hmm ok. So all my Programms should actually work, because they're alle installed locally, operated by the local user und also use the local word application.
|
|
|
|
|
Errrr, you know, it's hard to say... In my own experience, when Microsoft says something like "this will not work in these conditions" it really means "this will not work in some conditions".
Maybe in this case the problem is that you are trying to open the same file more than once at the same time, so it is locked as readonly from the second time unless you close the first one before.
Really, I would like to help you, but I'm afraid that the best advise I can give you is that you do what I usually do in these cases: if you know exactly when it fails and when it works, try a work-around to avoid the problem.
|
|
|
|
|
I am trying to read serial data from a microchip.
Using the simple serial c# project I am able to read the characters being sent, but I am not able to delineate carriage returns and so the correct data will stream across the screen until the programs input box end and then it will wrap around to the next line and continue to stream, an example would be
seveneightnineteneleventwelvethirteen
fourteenfifteensixteenseventeeneighteen
instead of
seven
eight
nine
ten
eleven
twelve
thirteen
fourteen
fifteen
sixteen
seventeen
eighteen
Does anyone know how I can recognize the carriage returns? They should come through as an ascii character "13" and the serial data protocol is 8 databits no paraty one stopbit (8N1) at a baudrate between 9600 and 115200 baud.
Thanks!
|
|
|
|
|
What have you tried? Are you checking each character as it arrives, or just passing the stream onto the input box?
Are you handling them as characters or bytes?
Post the relevant code fragments so we can tell what you are doing - that should help us to help you!
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
|
|
|
|
|
Hi,
Here is the guts of it
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
if (serialPort1.IsOpen) serialPort1.Close();
}
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
if(!serialPort1.IsOpen) return;
char[] buff = new char[1];
buff[0] = e.KeyChar;
serialPort1.Write(buff, 0, 1);
e.Handled = true;
}
private void DisplayText(object sender, EventArgs e)
{
textBox1.AppendText(RxString);
}
private void serialPort1_DataReceived
(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
RxString = serialPort1.ReadExisting();
this.Invoke(new EventHandler(DisplayText));
}
|
|
|
|
|
The first thing which springs to mind is:
Don't read the text into a string and invoke a routine to handle it. The only logical reason for doing that is to get the execution onto the GUI thread - which may not execute it immediately. If a single other character arrives in the mean time, it will discard your existing data. Better to get the data in the invoked method instead, or add it to a queue (my preference).
Regarding your problem with new lines: Are you sure you are receiving them? Remember that ReadExisting translates according tgo the encoding (Strings are generally Unicode, serial ports are generally ASCII). I would be tempted to either try using ReadLine instead of ReadExisting, or ReadAllBytes and display the data as Hex, at least in the early stages.
I also wouldn't want to use a TextBox - a ListBox might be better as it doesn't slow down lots when the strings start to get large.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
|
|
|
|
|
Hi OG,
What do you think about using a rich text box? That would be ideal for me. I do have to preface this that I am new to c# and o.o and changing parameters around sometimes FUBARs everything because I'm new.
I am sure I am receiving the (13) because I have a barebones serial reader application that can read them correctly.
With this statement
"Don't read the text into a string and invoke a routine to handle it. The only logical reason for doing that is to get the execution onto the GUI thread - which may not execute it immediately."
How would I add it to a queue, I'm hoping that the data will stream up to the data rate speed without issue. When it is going across the screen it does not appear to be missing bits in the string I am sending.
|
|
|
|
|
Luc seems to have covered it all pretty well in his answer - good luck!
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
|
|
|
|
|
I suspect your problem is with how ReadExisting() handles the carriage returns; it may well be expecting a carriage return line feed pair of characters, to indicate a new line.
If I am using Serial port for text data, I get the data as a byte array; and then convert it to a string, either using Encoding - Encoding.ASCII.GetString(myByteArrray) or manually processing each character if I need to handle specific bytes individually.
Off the top of my head, I can't remember if GetString will convert a striaght carriage return to a new line; but if not you can process each byue of the array in turn, detecting the carriage return and adding Environment.NewLine in it's place to the string.
Hope this helps.
|
|
|
|
|
Hi Colin,
Maybe I can send it different characters for a line feed ... do you happen to know what pair of characters is it expecting?
With the byte array, are you just filling it up with 8 bits, and then at the stop bit converting it to a string?
|
|
|
|
|
I expect it wants a carriage return followed by a line feed - 0x0d 0x0a
Reading a byte array is not that low a level; the SerialPort class gives you a method to read byte data - SerialPort.Read Method (Byte[], Int32, Int32).
You can use the BytesToRead property to see how many bytes there are in the buffer.
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
