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• Haskel dot (.) and dollar ($) composition: correct use.

  - by Robert Massaioli

  I have been reading Real World Haskell and I am nearing the end but a matter of style has been niggling at me to do with the (.) and ($) operators. When you write a function that is a composition of other functions you write it like: f = g . h But when you apply something to the end of those functions I write it like this: k = a $ b $ c $ value But the book would write it like this: k = a . b . c $ value Now to me they look functionally equivalent, they do the exact same thing in my eyes. However, the more I look, the more I see people writing their functions in the manner that the book does: compose with (.) first and then only at the end use ($) to append a value to evaluate the lot (nobody does it with many dollar compositions). Is there a reason for using the books way that is much better than using all ($) symbols? Or is there some best practice here that I am not getting? Or is it superfluous and I shouldn't be worrying about it at all? Thanks.

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• Getting unhandled error and connection get lost when a client tries to communicate with chat server in twisted

  - by user2433888

  from twisted.internet.protocol import Protocol,Factory from twisted.internet import reactor class ChatServer(Protocol): def connectionMade(self): print "A Client Has Connected" self.factory.clients.append(self) print"clients are ",self.factory.clients self.transport.write('Hello,Welcome to the telnet chat to sign in type aim:YOUR NAME HERE to send a messsage type msg:YOURMESSAGE '+'\n') def connectionLost(self,reason): self.factory.clients.remove(self) self.transport.write('Somebody was disconnected from the server') def dataReceived(self,data): #print "data is",data a = data.split(':') if len(a) > 1: command = a[0] content = a[1] msg="" if command =="iam": self.name + "has joined" elif command == "msg": ma=sg = self.name + ":" +content print msg for c in self.factory.clients: c.message(msg) def message(self,message): self.transport.write(message + '\n') factory = Factory() factory.protocol = ChatServer factory.clients = [] reactor.listenTCP(80,factory) print "Iphone Chat server started" reactor.run() The above code is running succesfully...but when i connect the client (by typing telnet localhost 80) to this chatserver and try to write message ,connection gets lost and following errors occurs : Iphone Chat server started A Client Has Connected clients are [<__main__.ChatServer instance at 0x024AC0A8>] Unhandled Error Traceback (most recent call last): File "C:\Python27\lib\site-packages\twisted\python\log.py", line 84, in callWithLogger return callWithContext({"system": lp}, func, *args, **kw) File "C:\Python27\lib\site-packages\twisted\python\log.py", line 69, in callWithContext return context.call({ILogContext: newCtx}, func, *args, **kw) File "C:\Python27\lib\site-packages\twisted\python\context.py", line 118, in callWithContext return self.currentContext().callWithContext(ctx, func, *args, **kw) File "C:\Python27\lib\site-packages\twisted\python\context.py", line 81, in callWithContext return func(*args,**kw) --- --- File "C:\Python27\lib\site-packages\twisted\internet\selectreactor.py", line 150, in _doReadOrWrite why = getattr(selectable, method)() File "C:\Python27\lib\site-packages\twisted\internet\tcp.py", line 199, in doRead rval = self.protocol.dataReceived(data) File "D:\chatserverultimate.py", line 21, in dataReceived content = a[1] exceptions.IndexError: list index out of range Where am I going wrong?

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• Why does this threading approach not work?

  - by Tomas Lycken

  I have a wierd problem with threading in an ASP.NET application. For some reason, when I run the code in the request thread, everything works as expected. But when I run it in a separate thread, nothing happens. This is verified by calling the below handler with the three flags "on", "off" and "larma" respectively - in the two first cases everything works, but in the latter nothing happens. What am I doing wrong here? In the web project I have a generic handler with the following code: If task = "on" Then Alarm.StartaLarm(personId) context.Response.Write("Larmet är PÅ") ElseIf task = "off" Then Alarm.StoppaLarm(personId) context.Response.Write("Larmet är AV") ElseIf task = "larma" Then Alarm.Larma(personId) context.Response.Write("Larmar... (stängs av automagiskt)") Else context.Response.Write("inget hände - task: " & task) End If The Alarm class has the following methods: Private Shared Sub Larma_Thread(ByVal personId As Integer) StartaLarm(personId) Thread.Sleep(1000 * 30) StoppaLarm(personId) End Sub Public Shared Sub StartaLarm(ByVal personId As Integer) SandSMS(True, personId) End Sub Public Shared Sub StoppaLarm(ByVal personId As Integer) SandSMS(False, personId) End Sub Public Shared Sub SandSMS(ByVal setOn As Boolean, ByVal personId As Integer) ... End Sub

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• How to get to the key name of a referenced entity property from an entity instance without a datastore read in google app engine?

  - by Sumeet Pareek

  Consider I have the following models - class Team(db.Model): # say I have just 5 teams name = db.StringProperty() class Player(db.Model): # say I have thousands of players name = db.StringProperty() team = db.ReferenceProperty(Team, collection_name="player_set") Key name for each Team entity = 'team_' , and for each Player entity = 'player_' By some prior arrangement I have a Team entity's (key_name, name) mapping available to me. For example (team_01, United States Of America), (team_02, Russia) etc I have to show all the players and their teams on a page. One way of doing this would be - players = Player.all().fetch(1000) # This is 1 DB read for player in players: # This will iterate 1000 times self.response.out.write(player.name) # This is obviously not a DB read self.response.out.write(player.team.name) #This is a total of 1x1000 = 1000 DB reads That is a 1001 DB reads for a silly thing. The interesting part is that when I do a db.to_dict() on players, it shows that for every player in that list there is 'name' of the player and there is the 'key_name' of the team available too. So how can I do the below ?? players = Player.all().fetch(1000) # This is 1 DB read for player in players: # This will iterate 1000 times self.response.out.write(player.name) # This is obviously not a DB read self.response.out.write(team_list[player.<SOME WAY OF GETTING TEAM KEY NAME>]) # Here 'team_list' already has (key_name, name) for all 5 teams I have been struggling with this for a long time. Have read every available documentation. I could just hug the person that can help me here :-) Disclaimer: The above problem description is not a real scenario. It is a simplified arrangement that represents my problem exactly. I have run into it in a rater complex and big GAE appication.

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• Line End Problem Reading with Scanner Class in Java

  - by dikbas

  I am not an experienced Java programmer and i'm trying to write some text to a file and then read it with Scanner. I know there are lots of ways of doing this, but i want to write records to file with delimiters, then read the pieces. The problem is so small. When I look the output some printing isn't seen(shown in below). I mean the bold line in the Output that is only written "Scanner". I would be appreciated if anyone can answer why "String: " isn't seen there. (Please answer just what i ask) I couldn't understand if it is a simple printing problem or a line end problem with "\r\n". Here is the code and output: import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.util.Scanner; public class Tmp { public static void main(String args[]) throws IOException { int i; boolean b; String str; FileWriter fout = new FileWriter("test.txt"); fout.write("Testing|10|true|two|false\r\n"); fout.write("Scanner|12|one|true|"); fout.close(); FileReader fin = new FileReader("Test.txt"); Scanner src = new Scanner(fin).useDelimiter("[|\\*]"); while (src.hasNext()) { if (src.hasNextInt()) { i = src.nextInt(); System.out.println("int: " + i); } else if (src.hasNextBoolean()) { b = src.nextBoolean(); System.out.println("boolean: " + b); } else { str = src.next(); System.out.println("String: " + str); } } fin.close(); } } Here is the output: String: Testing int: 10 boolean: true String: two String: false Scanner int: 12 String: one boolean: true

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• Haskell function composition (.) and function application ($) idioms: correct use.

  - by Robert Massaioli

  I have been reading Real World Haskell and I am nearing the end but a matter of style has been niggling at me to do with the (.) and ($) operators. When you write a function that is a composition of other functions you write it like: f = g . h But when you apply something to the end of those functions I write it like this: k = a $ b $ c $ value But the book would write it like this: k = a . b . c $ value Now to me they look functionally equivalent, they do the exact same thing in my eyes. However, the more I look, the more I see people writing their functions in the manner that the book does: compose with (.) first and then only at the end use ($) to append a value to evaluate the lot (nobody does it with many dollar compositions). Is there a reason for using the books way that is much better than using all ($) symbols? Or is there some best practice here that I am not getting? Or is it superfluous and I shouldn't be worrying about it at all? Thanks.

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• Python file iterator over a binary file with newer idiom.

  - by drewk

  In Python, for a binary file, I can write this: buf_size=1024*64 # this is an important size... with open(file, "rb") as f: while True: data=f.read(buf_size) if not data: break # deal with the data.... With a text file that I want to read line-by-line, I can write this: with open(file, "r") as file: for line in file: # deal with each line.... Which is shorthand for: with open(file, "r") as file: for line in iter(file.readline, ""): # deal with each line.... This idiom is documented in PEP 234 but I have failed to locate a similar idiom for binary files. I have tried this: >>> with open('dups.txt','rb') as f: ... for chunk in iter(f.read,''): ... i+=1 >>> i 1 # 30 MB file, i==1 means read in one go... I tried putting iter(f.read(buf_size),'') but that is a syntax error because of the parens after the callable in iter(). I know I could write a function, but is there way with the default idiom of for chunk in file: where I can use a buffer size versus a line oriented? Thanks for putting up with the Python newbie trying to write his first non-trivial and idiomatic Python script.

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• What goes into main function?

  - by Woltan

  I am looking for a best practice tip of what goes into the main function of a program using c++. Currently I think two approaches are possible. (Although the "margins" of those approaches can be arbitrarily close to each other) 1: Write a "Master"-class that receives the parameters passed to the main function and handle the complete program in that "Master"-class (Of course you also make use of other classes). Therefore the main function would be reduced to a minimum of lines. #include "MasterClass.h" int main(int args, char* argv[]) { MasterClass MC(args, argv); } 2: Write the "complete" program in the main function making use of user defined objects of course! However there are also global functions involved and the main function can get somewhat large. I am looking for some general guidelines of how to write the main function of a program in c++. I came across this issue by trying to write some unit test for the first approach, which is a little difficult since most of the methods are private. Thx in advance for any help, suggestion, link, ...

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• how to download data which upload to gae ,

  - by zjm1126

  this is my code : import os from google.appengine.ext import webapp from google.appengine.ext.webapp import template from google.appengine.ext.webapp.util import run_wsgi_app from google.appengine.ext import db #from login import htmlPrefix,get_current_user class MyModel(db.Model): blob = db.BlobProperty() class BaseRequestHandler(webapp.RequestHandler): def render_template(self, filename, template_args=None): if not template_args: template_args = {} path = os.path.join(os.path.dirname(__file__), 'templates', filename) self.response.out.write(template.render(path, template_args)) class upload(BaseRequestHandler): def get(self): self.render_template('index.html',) def post(self): file=self.request.get('file') obj = MyModel() obj.blob = db.Blob(file.encode('utf8')) obj.put() self.response.out.write('upload ok') class download(BaseRequestHandler): def get(self): #id=self.request.get('id') o = MyModel.all().get() #self.response.out.write(''.join('%s: %s <br/>' % (a, getattr(o, a)) for a in dir(o))) self.response.out.write(o) application = webapp.WSGIApplication( [ ('/?', upload), ('/download',download), ], debug=True ) def main(): run_wsgi_app(application) if __name__ == "__main__": main() my index.html is : <form action="/" method="post"> <input type="file" name="file" /> <input type="submit" /> </form> and it show : <__main__.MyModel object at 0x02506830> but ,i don't want to see this , i want to download it , how to change my code to run, thanks

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• JavaCard monitoring folder

  - by GxG

  I want to write a two way application: applet for javacard and an application in C#. I've got the C# covered but i want to know if with JavaCard i can monitor a folder on the memory and how would i go about doing that. I have a shared folder let's call it temp in which i want to store buffer information between the simulated smartcard and the C# application. The C# application will only read from that folder and display the information, but also it will write requests towards the smartcard. For example i simulate entering the PIN for the card. The applet will write a file containing available options and the C# application will read that file and display those options; from the C# app i will chose and option and write a request file in the same folder. This is when the smartcard which is monitoring that folder will read the request and issue a response. Can i make the smartcard monitor that folder? I was thinking of using encrypted XML files for the request/response operations. But simple .txt files are good to. I am limited to using JavaCard v2.2.1, and every operation has to be encrypted/decrypted. (with the ciphering i have no problem)

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• how to install a file handle in perl class

  - by Haiyuan Zhang

  please looku up the following code first. #! /usr/bin/perl package foo; sub new { my $pkg = shift; my $self = {}; my $self->{_fd} = undef; bless $self, $pkg; return $self; } sub Setfd { my $self = shift; my $fd = shift; $self_->{_fd} = $fd; } sub write { my $self = shift; print $self->{_fd} "hello word"; } my $foo = new foo; My intention is to store a file handle within a class using hash. the file handle is undefined at first, but can be initilized afterwards by calling Setfd function. then write can be called to actually write string "hello word" to a file indicated by the file handle, supposed that the file handle is the result of a success "write" open. but, perl compiler just complains that there are syntax error in the "print" line. can anyone of you tells me what's wrong here? thanks in advance.

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• How can I store and access a filehandle in a Perl class?

  - by Haiyuan Zhang

  please look at the following code first. #! /usr/bin/perl package foo; sub new { my $pkg = shift; my $self = {}; my $self->{_fd} = undef; bless $self, $pkg; return $self; } sub Setfd { my $self = shift; my $fd = shift; $self_->{_fd} = $fd; } sub write { my $self = shift; print $self->{_fd} "hello word"; } my $foo = new foo; My intention is to store a file handle within a class using hash. the file handle is undefined at first, but can be initilized afterwards by calling Setfd function. then write can be called to actually write string "hello word" to a file indicated by the file handle, supposed that the file handle is the result of a success "write" open. but, perl compiler just complains that there are syntax error in the "print" line. can anyone of you tells me what's wrong here? thanks in advance.

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• Is it possible to use a serial port like session in c#?

  - by Pandiya Chendur

  I am using serial port communication in my asp.net webform application... private bool sendSMS(int portNo, string mobNo, string details) { try { SerialPort SerialPort1 = new SerialPort(); SerialPort1.PortName = "COM" + portNo.ToString(); SerialPort1.BaudRate = 9600; SerialPort1.Parity = Parity.None; SerialPort1.DataBits = 8; SerialPort1.StopBits = StopBits.One; SerialPort1.RtsEnable = true; SerialPort1.DtrEnable = true; SerialPort1.Encoding.GetEncoder(); SerialPort1.ReceivedBytesThreshold = 1; SerialPort1.NewLine = Environment.NewLine; SerialPort1.Open(); SerialPort1.Write("AT" + SerialPort1.NewLine); Sleep(500); SerialPort1.Write("AT+CMGF=1" + SerialPort1.NewLine); Sleep(500); SerialPort1.Write("AT+CMGS=" + (char)34 + mobNo + (char)34 + SerialPort1.NewLine); Sleep(1000); SerialPort1.Write(details + (char)26); Sleep(2000); SerialPort1.Close(); } catch { } return true; } This method works when i send i single message... But when want to send sms in bulk opening and closing port everytime is not a good idea... So my question is it possible to use a serial port like session in c#?... When i open a port i want it to be open for 1 hour and then if my time expires i want to close the port and open it the next time... Any suggestion...

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• C# object (2 numbers) performing 2 calculations

  - by Chris

  I have a couple questions about creating a object (2 values) and how to "call" it. Initializing the object with: Tweetal t1, t2, t3, t4, t5, t6; t1 = new Tweetal(); //a: 0 , b = 0 t2 = new Tweetal(-2); //a: -2, b = -2 t3 = new Tweetal(5, 17); //a: 5, b = 17 t4 = new Tweetal(t3); //a:5, b = 17 Console.Write("t1 = " + t1); Console.Write("\tt2 = " + t2); Console.Write("\tt3 = " + t3); Console.Write("\tt4 = " + t4); Console.WriteLine("\n"); t1 = t1.Som(t2); t4 = t2.Som(t2); //...... Now the 2 things i want to do with this object are taking the SUM and the SUMNumber: Sum: t4 = t2.sum(t3); (this would result in t4: a:3 (-2+5), b: 15(-2+17) SumNumber: t1 = t3.sum(8) (this would result in t1: a:13 , b:25) Next is my code for the object (in a separate class), but how exactly do i perform the simple sum calculation when i call up for example t2 etc... public class Tweetal: Object { private int a; private int b; public Tweetal() { //??? //Sum(...,...) } public Tweetal(int a) { //??? //Sum(...,...) } public Tweetal(int a, int b) { //??? } public Tweetal(Tweetal //....) // to call upton the object if i request t1, t2, t3,... insteed of a direct number value) { // ???? } public void Sum(int aValue, int bValue) { //a = ??? //b = ??? //Sum(...,...) } public void SumNumber(int aValue, int bValue) { } public override string ToString() { return string.Format("({0}, {1})", a, b); }/*ToString*/ }

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• C++ template type deduction problem

  - by hamishmcn

  motivation: I would like to create a utility class so that instead of having to write: if( someVal == val1 || someVal == val2 || someVal == val3 ) I could instead write: if( is(someVal).in(val1, val2, val3) ) which is much closer to the mathematical 'a is an element of (b,c,d)' and also would save on a lot of typing when the variable name 'someVal' is long. Here is the code I have so far (for 2 and 3 values): template<class T> class is { private: T t_; public: is(T t) : t_(t) { } bool in(const T& v1, const T& v2) { return t_ == v1 || t_ == v2; } bool in(const T& v1, const T& v2, const T& v3) { return t_ == v1 || t_ == v2 || t_ == v3; } }; However it fails to compile if I write: is(1).in(3,4,5); instead I have to write is<int>(1).in(3,4,5); Which isn't too bad, but it would be better if somehow the compiler could figure out that the type is int with out me having to explicitly specify it. Is there anyway to do this or I am stuck with specifying it explicitly?

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• Fire Box doesnot support program based calling function

  - by manish

  on clicking any row of the following program... i am firinf on function mail file click....function just having alert message that shoes deffrent file name on the bases of clicking... *its working properly in IE .....FireBox N other browser function doesnot call on clicking on any row.. whats problem..please help me......i am writing code for your better awareness* For Each info In fsi Response.Write("<span id=" & " 'userijd'" & " onmouseup=" & "mailfileclick('" & info.Name & "')" & ";>") Response.Write("<td width=" & "16%" & " bgcolor=" & "#FFFFFF" & " style=" & "border-bottom-style:&nbsp;solid;&nbsp;border-bottom-width:&nbsp;1px" & " bordercolor=" & "#C0C0C0" & " nowrap" & ">") Response.Write("<font face=" & "Arial" & "style=" & "font-size:&nbsp;9pt" & " color=" & "#000000" & ">" & Mid(contents, InStr(contents, "Date: ") + Len("Date:"), 17) & "</font></td>") Response.Write("</span>") Next

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• How to wrtie a XML License Line in C#?

  - by Nano HE

  My want to write a XML file as this: <?xml version="1.0" encoding="UTF-8"?> <Equipment xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <License licenseId="" licensePath="" /> Some piece of my code attached here // Create a new file in D:\\ and set the encoding to UTF-8 XmlTextWriter textWriter = new XmlTextWriter("D:\\books.xml", System.Text.Encoding.UTF8); // Format automatically textWriter.Formatting = Formatting.Indented; // Opens the document textWriter.WriteStartDocument(); // Write the namespace declaration. textWriter.WriteStartElement("books", null); // Write the genre attribute. textWriter.WriteAttributeString("xmlns", "xsd", null, "http://www.w3.org/2001/XMLSchema"); textWriter.WriteAttributeString("xmlns", "xsi", null, "http://www.w3.org/2001/XMLSchema-instance"); And now I need to write the License Line below in C# <License licenseId="" licensePath="" /> But I don't know how to move on for I found the Line ended with the special / .Thank you.

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• C# Freq. Table with Random Values

  - by Sef

  Hello, I am trying to write a frequency program that will represent a bar diagram (in console code). The problem is i have no idea how exactly to caculate this frequency or how do i exactly then give the bars different heights according to there frequency (trough calculation). The frequency height is capped at 21. (meaning the bars go from 1 to 21, so the max bar height would be for example 21 stars(* as display sign for the bar itself). A calculation i have so far (although not sure if correct) for frequency: This array takes the random values generated: for (int j = 0; j < T.Length; j++) { T[j] = (MaxHeight* T[j]) / Ber.GreatestElement(T); Console.Write("{0,7}", T[j]); } This results in values between 0 and 21 -- Based on the values my bars should give a certain height compared to all the other frequency values. (for example 8000 could have 21 in height where 39 could have 1). To represent this diagram i used 2 for loops to display height and width (keep in mind i only wish to use Using System; to keep it to the "basics"). for (int height= 1; height<= 21; height++) { for (int width= 0; width<= 10; width++) { if(...??) { Console.Write("{0,7}", bar); // string bar= ("*"); } else { Console.Write("{0,7}", empty); } } Console.WriteLine(); } So so far i have a entire field filled with * and the random values generated along with their frequency value (although i have no idea if the freq value is properly calculated). I assume i need a if (.....) in the second for but i cannot seem to get further then this. Thanks in advance!

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• Writing a generic function that can take a Writer as well as an OutputStream

  - by ebruchez

  I wrote a couple of functions that look like this: def myWrite(os: OutputStream) = {} def myWrite(w: Writer) = {} Now both are very similar and I thought I would try to write a single parametrized version of the function. I started with a type with the two methods that are common in the Java OutputStream and Writer: type Writable[T] = { def close() : Unit def write(cbuf: Array[T], off: Int, len: Int): Unit } One issue is that OutputStream writes Byte and Writer writes Char, so I parametrized the type with T. Then I write my function: def myWrite[T, A[T] <: Writable[T]](out: A[T]) = {} and try to use it: val w = new java.io.StringWriter() myWrite(w) Result: <console>:9: error: type mismatch; found : java.io.StringWriter required: ?A[ ?T ] Note that implicit conversions are not applicable because they are ambiguous: both method any2ArrowAssoc in object Predef of type [A](x: A)ArrowAssoc[A] and method any2Ensuring in object Predef of type [A](x: A)Ensuring[A] are possible conversion functions from java.io.StringWriter to ?A[ ?T ] myWrite(w) I tried a few other combinations of types and parameters, to no avail so far. My question is whether there is a way of achieving this at all, and if so how. (Note that the implementation of myWrite will need, internally, to know the type T that parametrizes the write() method, because it needs to create a buffer as in new ArrayT.)

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• How to delay execution of a method in c#?

  - by Pandiya Chendur

  I have this if condition, if (sendSMS(Convert.ToInt32(DLComportNo.SelectedItem.Text), TxtDriMob.Text, TxtCliDet.Text) && sendSMS(Convert.ToInt32(DLComportNo.SelectedItem.Text), TxtCliMob.Text, TxtDriDet.Text)) { // I am inserting details to my db } and my sendSMS method looks like this, private bool sendSMS(int portNo, string mobNo, string details) { try { SerialPort SerialPort1 = new SerialPort(); SerialPort1.PortName = "COM" + portNo.ToString(); SerialPort1.BaudRate = 9600; SerialPort1.Parity = Parity.None; SerialPort1.DataBits = 8; SerialPort1.StopBits = StopBits.One; SerialPort1.RtsEnable = true; SerialPort1.DtrEnable = true; SerialPort1.Encoding.GetEncoder(); SerialPort1.ReceivedBytesThreshold = 1; SerialPort1.NewLine = Environment.NewLine; SerialPort1.Open(); SerialPort1.Write("AT" + SerialPort1.NewLine); Sleep(500); SerialPort1.Write("AT+CMGF=1" + SerialPort1.NewLine); Sleep(500); SerialPort1.Write("AT+CMGS=" + (char)34 + mobNo + (char)34 + SerialPort1.NewLine); Sleep(1000); SerialPort1.Write(details + (char)26); Sleep(2000); SerialPort1.Close(); } catch { } return true; } What happens is when i use break point in my sendSMS i get my output (ie) both the methods get executed and messages are sent properly... But when i removed my breakpoint both the methods in the if statement are executed but message from the first method is sent and not from the second method.... Any suggestion?

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• Saving information in the IO System

  - by djTeller

  Hi Kernel Gurus, I need to write a kernel module that simulate a "multicaster" Using the /proc file system. Basically it need to support the following scenarios: 1) allow one write access to the /proc file and many read accesses to the /proc file. 2) The module should have a buffer of the contents last successful write. Each write should be matched by a read from all reader. Consider scenario 2, a writer wrote something and there are two readers (A and B), A read the content of the buffer, and then A tried to read again, in this case it should go into a wait_queue and wait for the next message, it should not get the same buffer again. I need to keep a map of all the pid's that already read the current buffer, and in case they try to read again and the buffer was not changed, they should be blocked until there is a new buffer. I'm trying to figure it there is a way i can save that info without a map. I heard there are some redundant fields inside the I/O system the I can use to flag a process if it already read the current buffer. Can someone give me a tip where should i look for that field ? how can i save info on the current process without keeping a "map" of pid's and buffers ? Thanks!

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• File being used by another process. Reason, and solution?

  - by pstar

  The process cannot access the file 'abc.log' because it is being used by another process. Hi, I've seen this exception from my application occationaly but I am still trying to fix that, hope I will get some insight from stackoverflow. In my application I've have defined a WriteToLog function which will write to a log file. Also the mainForm of my application will launch a backgroundWorker do some job which also calls the WriteToLog. Maybe two threads access a file will cause a problem? But in my code I 've already do my best to write flush and close the text file (I think), and here is my code from WriteToLog: StreamWriter sw = null; string newText = ""; try { //populate the content for newText sw = File.AppendText(LOG_FILE); sw.Write(newText); sw.Flush(); sw.Close(); } catch (IOException ex) { MessageBox.Show("Failed to write to log!\n\t" + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } finally { if (sw != null) { sw.Close(); } } I think as long as I flush and close the streamWriter, I should be able call the WriteToLog multi-times and in multi-threads isn't it? Or if I am wrong, could I simple make the file open shared, or there are other reason/solutions?

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• Serial Data Not Transmitted in C# Application

  - by Jim Fell

  Hello. I have a C# application wherein serial (COM1) data appears to sometimes not get transmitted. Following is a simplified snippet of my code (calls to textBox writes have been removed): try { serialPort1.Write("D"); serialPort1.Write(msg, 0, 512); serialPort1.Write("d"); serialPort1.Write(pCsum, 0, 2); } catch (SystemException ex) { /* ... */ } What is odd is that this same code works just fine when the port is configured for 115.2Kbps. However, when running at 9600bps data that should be transmitted by this code seems to not get transmitted. I have verified this by monitoring the receive flag on the remote device. No exceptions are thrown from within the try statement. Is there something else (Flush, etc.) that I should be doing to make sure the data is transmitted? Any thoughts or suggestions you may have would be appreciated. I'm using Microsoft Visual C# 2008 Express Edition. Thanks.

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• Writing JavaScript from a Custom Control

  - by coffeeaddict

  I'm new to writing custom controls. I have MyCustomControl.cs and in my Render method I want to render out about 50 lines of JavaScript. What's the best way to do this, use the writer? protected override void Render(HtmlTextWriter writer) { writer.write(@"<script type....rest of opening tag here"); writer.Write(@" function decode(s) { return s.replace(/&amp;/g, ""&"") .replace(/&quot;/g, '""') .replace(/&#039;/g, ""'"") .replace(/&lt;/g, ""<"") .replace(/&gt;/g, "">""); };" ); I plan on having around 6 more writer.Write to write out some more sections here. Is that the best approach to actually perform the writing of JavaScript in this manor? or should I use ClientScript.RegisterClientScriptBlock? So what's the best practice or common way people are writing javascript from a custom control? (I'm not talking about a user control here!!, custom control/Class!) I also want to keep any indentation for readability once it's spit out/rendered on the client when viewing source.

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• How to replace same text in a text file

  - by user1688220

  i created a c# windows login form and i am saving username or password to a text file but every time i use same username or password that i have saved before it takes new place in that text file. But What i want is to replace the same username or password that is already saved in that text file. this is my code: private void button1_Click(object sender, EventArgs e) { try { FileStream fs = new FileStream("data.txt", FileMode.Append, FileAccess.Write); StreamWriter sw = new StreamWriter(fs); sw.Write("Email ID: "); sw.WriteLine(textBox1.Text); sw.Write("Password: "); sw.Write(textBox2.Text); sw.WriteLine(); sw.WriteLine(); sw.Flush(); sw.Close(); fs.Close(); } catch (Exception) { MessageBox.Show("Error", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); this.Close(); } MessageBox.Show("DONE", "Done", MessageBoxButtons.OK, MessageBoxIcon.Information); textBox1.Clear(); textBox2.Clear(); }

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