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• multiple clients - one server connection with sockets tcp/ip c# .net

  - by jagse

  Hello guys, I need to develop a client server system where I can have multiple clients communicating with one server at the same time. I want to communicate xml serialized objects and also need to send and receive other commands to invoke methods. Now, I am just starting with socket programming in C# and .Net and found that the asynchronous I/O is the way to go so that the methods dont block the execution of code. Also there are many examples of how to make a simple client server system. So I have a basic understanding of how that works. Anyway, what still is not clear to me is how I can set up a server which can manage connections to multiple clients? Can I just create a new socket per connection and then store those in some kind of list? Do I need some kind of multiplexing to achieve this? Do I have to listen at multiple ports? What`s the best way here? And the other thing is if I need to develop my own protocol to differentiate between what I am actually sending over the network -- xml serialized object or a command which might be just a string encoded in ascII or something. Or would I develop my own protocol just to send these commands? Any kind of help is apreciated! If someone knows a good book which covers this sort of stuff, let me know. Cheers I forgot to mention that some of my clients which are supposed to communicate with my server will be pda and I therefore use the compact framework... So this might bring in some restrictions...

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• What makes an effective UI for displaying versioning of structured hierarchical data

  - by Fadrian Sudaman

  Traditional version control system are displaying versioning information by grouping Projects-Folders-Files with Tree view on the left and details view on the right, then you will click on each item to look at revision history for that configuration history. Assuming that I have all the historical versioning information available for a project from Object-oriented model perspective (e.g. classes - methods - parameters and etc), what do you think will be the most effective way to present such information in UI so that you can easily navigate and access the snapshot view of the project and also the historical versioning information? Put yourself in the position that you are using a tool like this everyday in your job like you are currently using SVN, SS, Perforce or any VCS system, what will contribute to the usability, productivity and effectiveness of the tool. I personally find the classical way for display folders and files like above are very restrictive and less effective for displaying deep nested logical models. Assuming that this is a greenfield project and not restricted by specific technology, how do you think I should best approach this? I am looking for idea and input here to add values to my research project. Feel free to make any suggestions that you think is valuable. Thanks again for anyone that shares their thoughts.

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• Modify SQL result set before returning from stored procedure

  - by m0sa

  I have a simple table in my SQL Server 2008 DB: Tasks_Table -id -task_complete -task_active -column_1 -.. -column_N The table stores instructions for uncompleted tasks that have to be executed by a service. I want to be able to scale my system in future. Until now only 1 service on 1 computer read from the table. I have a stored procedure, that selects all uncompleted and inactive tasks. As the service begins to process tasks it updates the task_active flag in all the returned rows. To enable scaleing of the system I want to enable deployment of the service on more machines. Because I want to prevent a task being returned to more than 1 service I have to update the stored procedure that returns uncompleted and inactive tasks. I figured that i have to lock the table (only 1 reader at a time - I know I have to use an apropriate ISOLATION LEVEL), and updates the task_active flag in each row of the result set before returning the result set. So my question is how to modify the SELECT result set iin the stored procedure before returning it?

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• I have problem using vesijama (Very Simple Java Mail)

  - by Huuhaacece

  Hi, i already read this tutorial from here and i have download all required libraries (Log4j, JavaMail API ,Activation framework) . But when i trying running this program i got this error log4j:WARN No appenders could be found for logger (org.codemonkey.vesijama.Mailer). org.codemonkey.vesijama.MailException: Generic error: Exception reading response log4j:WARN Please initialize the log4j system properly. this is the source code i use import javax.mail.Message.RecipientType; import org.codemonkey.vesijama.Email; import org.codemonkey.vesijama.MailException; import org.codemonkey.vesijama.Mailer; public class testSend { final Email email = new Email(); public testSend{ try{ email.setFromAddress("test", "[email protected]"); email.setSubject("hey"); email.addRecipient("hai", "[email protected]", RecipientType.TO); email.setText("We should meet up!"); email.setTextHTML("<b>We should meet up!</b>"); new Mailer("smtp.gmail.com", 465, "[email protected]", "XXXXXX").sendMail(email); } catch(MailException me) { System.out.println(me); } } } i have also trying using port 587. but i got same error .< btw , it say can add attachments what should i write if i want to attach .xls ( microsoft excel 2003) ? Thx B4.

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• Working with libpath with java reflection.

  - by C. Ross

  I'm dynamically loading a class and calling a method on it. This class does JNI. When I call the class, java attempts to load the library. This causes an error because the library is not on the libpath. I'm calling from instead a jar so I can't easily change the libpath (especially since the library is not in the same directory or a sub directory of the jar). I do know the path of the library, but how can I load it before I load the class. Current code: public Class<?> loadClass(String name) throws ClassNotFoundException { if(!CLASS_NAME.equals(name)) return super.loadClass(name); try { URL myUrl = new URL(classFileUrl); URLConnection connection = myUrl.openConnection(); InputStream input = connection.getInputStream(); byte[] classData = readConnectionToArray(input); return defineClass(CLASS_NAME, classData, 0, classData.length); } catch (MalformedURLException e) { throw new UndeclaredThrowableException(e); } catch (IOException e) { throw new UndeclaredThrowableException(e); } } Exception: Can't find library libvcommon.so java.lang.UnsatisfiedLinkError: vcommon (A file or directory in the path name does not exist.) at java.lang.ClassLoader.loadLibraryWithPath(ClassLoader.java:998) at java.lang.ClassLoader.loadLibraryWithClassLoader(ClassLoader.java:962) at java.lang.System.loadLibrary(System.java:465) at vcommon.(vcommon.java:103) at java.lang.J9VMInternals.initializeImpl(Native Method) at java.lang.J9VMInternals.initialize(J9VMInternals.java:200) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) at java.lang.reflect.Method.invoke(Method.java:599) at com.fortune500.fin.v.vunit.reflection.ReflectionvProcessor.calculateV(ReflectionvProcessor.java:36) at com.fortune500.fin.v.vunit.UTLTestCase.execute(UTLTestCase.java:42) at com.fortune500.fin.v.vunit.TestSuite.execute(TestSuite.java:15) at com.fortune500.fin.v.vunit.batch.Testvendor.execute(Testvendor.java:101) at com.fortune500.fin.v.vunit.batch.Testvendor.main(Testvendor.java:58) Related: Dynamic loading a class in java with a different package name

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• Delphi fastMM doesn't work with operator "IS"

  - by Joc02

  I work on Delphi project who interac with many other small libraries. I use FastMM4 and I would like work with complex classes passed on dll parameter. So for exemple I send my form to my dll. Into the dll I test the type of parameter with the operator "IS". But into the Dll the operator "IS" return always "false" Exemple library Dll; uses FastMM4, System.SysUtils, System.Classes, Vcl.Dialogs, Vcl.Forms; {$R *.res} procedure Complex(L : TObject);stdcall; begin if L is TForm then showmessage('Ok') else showmessage('Pas ok') ; if L is TCustomFrame then showmessage('Ok') else showmessage('Pas ok') end; exports Complex; begin end. And the call procedure TffsIsOperator.Button2Click(Sender: TObject); var MaDLL : THandle; Proc : procedure (l : TForm); begin try MaDLL := LoadLibrary(PChar('Dll.dll')); @Proc := GetProcAddress(MaDLL, 'Complex'); Proc(self); finally FreeLibrary(MaDLL); end; end;

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• ASP.NET MVC 2 user input to SQL 2008 Database problems

  - by Rob

  After my publish in VS2010 the entire website loads and pulls data from the database perfectly. I can even create new users through the site with the correct key code, given out to who needs access. I have two connection strings in my web.config file The first: <add xdt:Transform="SetAttributes" xdt:Locator="Match(name)" name="EveModelContainer" connectionString="metadata=res://*/Models.EdmModel.EveModel.csdl|res://*/Models.EdmModel.EveModel.ssdl|res://*/Models.EdmModel.EveModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=localhost;Initial Catalog=fleet;Persist Security Info=True;User ID=fleet;Password=****&quot;" providerName="System.Data.EntityClient" /> The second: <add xdt:Transform="SetAttributes" xdt:Locator="Match(name)" name="ApplicationServices" connectionString="Data Source=localhost;Initial Catalog=fleet;Persist Security Info=True;User ID=fleet;Password=****;MultipleActiveResultSets=True" /> The first one is the one that is needed to post data with the main application, EveModelContainer. Everything else is pulled using the standard ApplicationServices connection. Do you see anything wrong with my connectionstring? I'm at a complete loss here. The site works perfectly on my friends server and not on mine... Could it be a provider issue? And if I go to iis 7's manager console, and click .net users I get a pop up message saying the custom provider isn't a trusted provider do I want to allow it to run at a higher trust level. I'm at the point where I think its either my string or this trusted provider error... but I have no clue how to add to the trusted provider list... Thank you in advance!!!

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• Measuring time spent in application / thread

  - by Adamski

  I am writing a simulation in Java whereby objects act under Newtonian physics. An object may have a force applied to it and the resulting velocity causes it to move across the screen. The nature of the simulation means that objects move in discrete steps depending on the time ellapsed between the current and previous iteration of the animation loop; e.g public void animationLoop() { long prev = System.currentTimeMillis(); long now; while(true) { long now = System.currentTimeMillis(); long deltaMillis = now - prev; prev = now; if (deltaMillis > 0) { // Some time has passed for (Mass m : masses) { m.updatePosition(deltaMillis); } // Do all repaints. } } } A problem arises if the animation thread is delayed in some way causing a large amount of time to ellapse (the classic case being under Windows whereby clicking and holding on minimise / maximise prevents a repaint), which causes objects to move at an alarming rate. My question: Is there a way to determine the time spent in the animation thread rather than the wallclock time, or can anyone suggest a workaround to avoid this problem? My only thought so far is to contstrain deltaMillis by some upper bound.

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• Create static instances of a class inside said class in Python

  - by Samir Talwar

  Apologies if I've got the terminology wrong here—I can't think what this particular idiom would be called. I've been trying to create a Python 3 class that statically declares instances of itself inside itself—sort of like an enum would work. Here's a simplified version of the code I wrote: class Test: A = Test("A") B = Test("B") def __init__(self, value): self.value = value def __str__(self): return "Test: " + self.value print(str(Test.A)) print(str(Test.B)) Writing this, I got an exception on line 2 (A = Test("A")). I assume line 3 would also error if it had made it that far. Using __class__ instead of Test gives the same error. File "<stdin>", line 1, in <module> File "<stdin>", line 2, in Test NameError: name 'Test' is not defined Is there any way to refer to the current class in a static context in Python? I could declare these particular variables outside the class or in a separate class, but for clarity's sake, I'd rather not if I can help it. To better demonstrate what I'm trying to do, here's the same example in Java: public class Test { private static final Test A = new Test("A"); private static final Test B = new Test("B"); private final String value; public Test(String value) { this.value = value; } public String toString() { return "Test: " + value; } public static void main(String[] args) { System.out.println(A); System.out.println(B); } } This works as you would expect: it prints: Test: A Test: B How can I do the same thing in Python?

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• Multithreading A Function in VB.Net

  - by Ben

  I am trying to multi thread my application so as it is visible while it is executing the process, this is what I have so far: Private Sub SendPOST(ByVal URL As String) Try Dim DataBytes As Byte() = Encoding.ASCII.GetBytes("") Dim Request As HttpWebRequest = TryCast(WebRequest.Create(URL.Trim & "/webdav/"), HttpWebRequest) Request.Method = "POST" Request.ContentType = "application/x-www-form-urlencoded" Request.ContentLength = DataBytes.Length Request.Timeout = 1000 Request.ReadWriteTimeout = 1000 Dim PostData As Stream = Request.GetRequestStream() PostData.Write(DataBytes, 0, DataBytes.Length) Dim Response As WebResponse = Request.GetResponse() Dim ResponseStream As Stream = Response.GetResponseStream() Dim StreamReader As New IO.StreamReader(ResponseStream) Dim Text As String = StreamReader.ReadToEnd() PostData.Close() Catch ex As Exception If ex.ToString.Contains("401") Then TextBox2.Text = TextBox2.Text & URL & "/webdav/" & vbNewLine End If End Try End Sub Public Sub G0() Dim siteSplit() As String = TextBox1.Text.Split(vbNewLine) For i = 0 To siteSplit.Count - 1 Try If siteSplit(i).Contains("http://") Then SendPOST(siteSplit(i).Trim) Else SendPOST("http://" & siteSplit(i).Trim) End If Catch ex As Exception End Try Next End Sub Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Dim t As Thread t = New Thread(AddressOf Me.G0) t.Start() End Sub However, the 'G0' sub code is not being executed at all, and I need to multi thread the 'SendPOST' as that is what slows the application.

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• Problem with loading a PNG image in JApplet.

  - by Bruce

  Hi there, I'm trying to load a PNG image from JAR file when running JApplet. The file is, I think, loaded properly - there are no errors. However it is not displayed. img.png is placed in the same directory as MainClass.java file. Here is the code: InputStream imageURL = this.getClass().getResourceAsStream("img.png" ); byte[] bytes = null; try {bytes = new byte[imageURL.available()]; System.out.println(imageURL.available()); imageURL.read(bytes);} catch(Exception e) {System.out.println("bleah");} Image image = Toolkit.getDefaultToolkit().createImage(bytes); Image imageScaled = me.getScaledInstance( 100, 150, Image.SCALE_SMOOTH ); jLabel6 = new javax.swing.JLabel( new ImageIcon( imageScaled) ); and the HTML exerpt: <APPLET codebase="classes" code="myapplet/MainClass.class" archive ="LittleApplet.jar" width=700 height=500> The image, as I wrote, is probably read, but not displayed in JLabel. What am I missing/doing wrong? Thanks in advance for the reply!

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• Best solution for an StringToInt function in C#

  - by StefanE

  Hi, I were asked to do an StringToInt / Int.parse function on the white board in an job interview last week and did not perform very good but I came up with some sort of solution. Later when back home I made one in Visual Studion and I wonder if there are any better solution than mine below. Have not bothred with any more error handling except checking that the string only contains digits. private int StrToInt(string tmpString) { int tmpResult = 0; System.Text.Encoding ascii = System.Text.Encoding.ASCII; byte[] tmpByte = ascii.GetBytes(tmpString); for (int i = 0; i <= tmpString.Length-1; i++) { // Check whatever the Character is an valid digit if (tmpByte[i] > 47 && tmpByte[i] <= 58) // Here I'm using the lenght-1 of the string to set the power and multiply this to the value tmpResult += (tmpByte[i] - 48) * ((int)Math.Pow(10, (tmpString.Length-i)-1)); else throw new Exception("Non valid character in string"); } return tmpResult; }

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• C++ Builder 2010 Exception Dead Lock ???

  - by James

  Hello Is this some kind of exception dead lock i am facing? How to avoid it ? Have a look at below line where i have TIdContext objects of connected clients stored in an objlist and at times i need to process it. But if one user is disconnected while another thread is processing the list, then for that freed TIdContext-Data object I am getting Access voilation, Ok its fine i am using try/catch but problem is that at below line there is some kind of dead lock and process hangs , if i attach a debuger it show Access voilation Again and Again and Again, and cpu coonsumption goes up because of that exception dead lock. AnsiString UserID = ((Tmyobject*) ((TIdContext*) ObjList->Objects[i])->Data)->UserID; i know i can check before accessing the object, if object is not Null, It works.. But my question is what if once in a blue moon the Data object is freed at the point when NULL check is performed and on next line when again i am accessing the object i get same dead lock ??? So how to avoid/handle this dead lock exception ? Here is the call stack... :005F07C0 System::AnsiStringBase::AnsiStringBase(this=:0285FCE0, src=????) :0040223F System::AnsiStringT<0>::AnsiStringT<0>(this=:0285FCE0, src=:00000008) :00457996 TSomeClass::SomeFunction(this=:009D8230, UserID={ }, DataSize={ }, ) :0047BFF1 __linkproc__ ThreadProc(Thread=:009561C0) :004AD00E __linkproc__ ThreadWrapper(Parameter=:009EAA30) :7c80b729 ; C:\WINDOWS\system32\kernel32.dll Please helppppppppppppppppppppp Thanks

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• Gathering entropy in web apps to create (more) secure random numbers

  - by H M

  after several days of research and discussion i came up with this method to gather entropy from visitors (u can see the history of my research here) when a user visits i run this code: $entropy=sha1(microtime().$pepper.$_SERVER['REMOTE_ADDR'].$_SERVER['REMOTE_PORT']. $_SERVER['HTTP_USER_AGENT'].serialize($_POST).serialize($_GET).serialize($_COOKIE)); note: pepper is a per site/setup random string set by hand. then i execute the following (My)SQL query: $query="update `crypto` set `value`=sha1(concat(`value`, '$entropy')) where name='entropy'"; that means we combine the entropy of the visitor's request with the others' gathered already. that's all. then when we want to generate random numbers we combine the gathered entropy with the output: $query="select `value` from `crypto` where `name`='entropy'"; //... extract(unpack('Nrandom', pack('H*', sha1(mt_rand(0, 0x7FFFFFFF).$entropy.microtime())))); note: the last line is a part of a modified version of the crypt_rand function of the phpseclib. please tell me your opinion about the scheme and other ideas/info regarding entropy gathering/random number generation. ps: i know about randomness sources like /dev/urandom. this system is just an auxiliary system or (when we don't have (access to) these sources) a fallback scheme.

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• Modelling in Agile Development

  - by bertzzie

  I'm writing a bachelor dissertation report where I'm developing a system with Agile methodology. Given that the development is an one man show, of course the "Agile" I did was not really agile at all (from my understanding at least). So I want some perspective from SO crowds, who is of course a professional, real world, developer with tons of experience. I think real world experience is better than the theory and experiments that I did. My question is: Do we model during development time when using Agile? UML? DFD? Or a Functional Specification is enough1? If modelling is not really necessary, what do we use to communicate to the user, as the user almost always won't understand UML or DFD? For my system, I use UI & UX Design with heavy prototyping, but then I don't have time to draw UML any more. Which one is better? 1 http://www.joelonsoftware.com/articles/fog0000000036.html I hope the question's not "subjective and argumentative" as I know this question exist because of my lack of understanding in the agile development. If it is, could someone just give me a pointer or reference about that? Possible duplicate: Do you use UML in Agile development practices?

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• how do i insert html file that have hebrew text and read it back in sql server 2008 using the filest

  - by gadym

  hello all, i am new to the filestream option in sql server 2008, but i have already understand how to open this option and how to create a table that allow you to save files. let say my table contains: id,name, filecontent i tried to insert an html file (that has hebrew chars/text in it) to this table. i'm writing in asp.net (c#), using visual studio 2008. but when i tried to read back the content , hebrew char becomes '?'. the actions i took were: 1. i read the file like this: // open the stream reader System.IO.StreamReader aFile = new StreamReader(FileName, System.Text.UTF8Encoding.UTF8); // reads the file to the end stream = aFile.ReadToEnd(); // closes the file aFile.Close(); return stream; // returns the stream i inserted the 'stream' to the filecontent column as binary data. i tried to do a 'select' to this column and the data did return (after i coverted it back to string) but hebrew chars become '?' how do i solve this problem ? what I should pay attention to ? thanks, gadym

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• How is external memory, internal memory, and cache organized?

  - by goldenmean

  Consider a system as follows:= A hardware board having say ARM Cortex-A8 and Neon Vector coprocessor, and Embedded Linux OS running on Cortex-A8. On this environment, if there is some application - say, a video decoder is executing - then: How is it decided that which buffers would be in external memory, which ones would be allocated in internal SRAM, etc. When one says calloc/malloc on such system/code, the pointer returned is from which memory: internal or external? Can a user make buffers to be allocated to the memories of his choice (internal/external)? In ARM architectures, there is another memory called as Tightly coupled memory (TCM). What is that and how can user enable and use it? Can I declare buffers in this memory? Do I need to see the memory map (if any) of the hardware board to understand about all these different physical memories present in a typical hardware board? How much of a role does the OS play in distinguishing these different memories? Sorry for multiple questions, but i think they all are interlinked.

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• ASP Force Download

  - by Thomas Clayson

  In PHP I can do: header("Content-type: application/octet-stream") and then anything that I output is downloaded instead of showing in the browser. Is there a similar way to do this in ASP? I have seen about all the file streaming and such using ADODB.Stream, but that doesn't seem to work for me and always requires another file to load the content from. Bit of an ASP noob, so go easy on me. :p All I want to do is have a script that outputs a CSV and that will force download instead of showing in the browser. Thanks EDIT here is my script currently: reportingForce.aspx.vb Public Class reportingForce Inherits System.Web.UI.Page Dim FStream Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Response.Buffer = True Response.ContentType = "application/octet-stream" Response.AddHeader("Content-disposition", "attachment; filename=" & Chr(34) & "my output file.csv" & Chr(34)) Response.Write("1,2,3,4,5" & vbCrLf) Response.Write("5,6,7,8,9" & vbCrLf) End Sub End Class reportingForce.aspx Hello,World

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• How to globalize ASP.NET MVC views (decimal separators in particular)?

  - by Pawel Krakowiak

  I'm working with the NerdDinner sample application and arrived at the section which deals with the Virtual Earth map. The application stores some values for the longitude and latitude. Unfortunately on my system floating point numbers are stored with a comma as the decimal separator, not a dot like in the US. So if I have a latitude of 47.64 it's retrieved and displayed as 47,64. Because that value is passed in a function call to the Virtual Earth API it fails at that point (e.g. JavaScript API expects 47.64, -122.13, but gets 47,64, -122,13). I need to make sure that the application always uses dots. In a WebForms app I would have a common class which overrides the System.Web.UI.Page.InitializeCulture() method and I would be inheriting my pages from that class. I am not sure about how to do the same with MVC. Do I need a customized ViewPage or something? Is there an easy way to solve this? Examples?

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• Visual Basic Express 2008 Help

  - by khalidfazeli

  I have been given a task to: Develop a program where a child will be presented with picture of a fruit (one of five possible fruit) on the screen at the click of a start button. The child will then try to recognise the fruit and write its name in a specified place on the screen. On the click of a check button the name of the fruit written by the child will be checked by your program and if correct will reward the child with a suitable message. If the name presented by the child is not correct, a suitable message should be presented on a red background with the correct name of the fruit included in the message. so far I have managed to create a form with 5 different fruit pictures and a text box below them. a button at the bottom of the form then checks the results and presents a message box to tell them if they have passed or failed. Private Sub btnResults_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnResults.Click If txtApple.Text = "APPLE" And txtOrange.Text = "ORANGES" And txtStrawberry.Text = "STRAWBERRIES" And txtGrapes.Text = "GRAPES" And txtBanana.Text = "BANANAS" Then MsgBox("Congratulations! you got it all right!", MsgBoxStyle.OkOnly) End Else MsgBox("Incorrect, please try again", MsgBoxStyle.OkOnly) End End If End Sub but I can't get it to randomise the picture of the fruit, so it only displays one fruit at a time and checks against it. Any help is appreciated. Thanks

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• Firefox proxy dilemma

  - by Mike L.

  Any idea why when using system proxy settings in firefox, it can not accept a proxy such as: user:[email protected]:port ??? IE will allow and connect to a proxy in this format. Not only does firefox not work, but it does not prompt for the password, nor attempt to make a connection to the proxy. Basically get a "proxy server not found" error. Anybody know a way around this? I am working on a proxy switching program for IE & Firefox, and I would like to use system-wide proxy settings. If I just store the server:port combination, firefox prompts for the password, as well as IE. Then they can be cached and it will not ask again. Maybe my only option is to programmatically cache the user/pass? Anybody know a way to do this? I am pretty sure IE stores them at HTTP basic authentication passwords and I can add them with AddCredential. After saving a password for a proxy in firefox, it shows up in saved passwords in a format like "moz-proxy://server:port" anybody know how to programmatically add a saved password to firefox? Thanks

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• Do you like languages that let you put the "then" before the "if"?

  - by Matt Hamilton

  I was reading through some C# code of mine today and found this line: if (ProgenyList.ItemContainerGenerator.Status != System.Windows.Controls.Primitives.GeneratorStatus.ContainersGenerated) return; Notice that you can tell without scrolling that it's an "if" statement that works with ItemContainerGenerator.Status, but you can't easily tell that if the "if" clause evaluates to "false" the method will return at that point. Realistically I should have moved the "return" statement to a line by itself, but it got me thinking about languages that allow the "then" part of the statement first. If C# permitted it, the line could look like this: return if (ProgenyList.ItemContainerGenerator.Status != System.Windows.Controls.Primitives.GeneratorStatus.ContainersGenerated); This might be a bit "argumentative", but I'm wondering what people think about this kind of construct. It might serve to make lines like the one above more readable, but it also might be disastrous. Imagine this code: return 3 if (x > y); Logically we can only return if x y, because there's no "else", but part of me looks at that and thinks, "are we still returning if x <= y? If so, what are we returning?" What do you think of the "then before the if" construct? Does it exist in your language of choice? Do you use it often? Would C# benefit from it?

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• How do I implement configurations and settings?

  - by Malvolio

  I'm writing a system that is deployed in several places and each site needs its own configurations and settings. A "configuration" is a named value that is necessary to a particular site (e.g., the database URL, S3 bucket name); every configuration is necessary, there is not usually a default, and it's typically string-valued. A setting is a named value but it just tweaks the behavior of the system; it's often numeric or Boolean, and there's usually some default. So far, I've been using property files or thing like them, but it's a terrible solution. Several times, a developer has added a requirement for a configuration but not added the value to file for the live configuration, so the new release passed all the tests, then failed when released to live. Better, of course, for every file to be compiled — so if there's a missing configuration, or one of the wrong type, it won't get past the compiler — and inject the site-specific class into the build for each site. As a bones, a Scala file can easy model more complex values, especially lists, but also maps and tuples. The downside is, the files are sometimes maintained by people who aren't developers, so it has to be pretty self-explanatory, which was the advantage of property files. (Someone explain XML configurations to me: all the complexity of a compilable file but the run-time risk of a property file.) What I'm looking for is an easy pattern for defining a group required names and allowable values. Any suggestions?

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• passing an "unknown enumeration" to a method

  - by firoso

  I'm currently trying to make a class that can register strings as identifiers and accociate them with different types of Enumerations, these enumerations are being evaluated only in so much that I am ensuring that when it's used, that the parameter passed to broadcast (messageType) is an instance of the associated Enum Type. This would work something like this: Diagnostics.RegisterIdentifier("logger", typeof(TestEnum)); Diagnostics.Broadcast("logger", TestEnum.Info, null, "Hello World", null); here's the code I currently have, I need to be able to verify that messageTypesEnum is contained in messageTypesFromIdentifier. private static Dictionary<string, Type> identifierMessageTypeMapping = new Dictionary<string, Type>(); private static List<IListener> listeners = new List<IListener>(); public static void RegisterIdentifier(string identifier, Type messageTypesEnum) { if (messageTypesEnum.BaseType.FullName == "System.Enum") { identifierMessageTypeMapping.Add(identifier, messageTypesEnum); } else { throw new ArgumentException("Expected type of messageTypesEnum to derive from System.Enum", "messageTypesEnum"); } } public static void Broadcast(string identifier, object messageType, string metaIdentifier, string message, Exception exception) { if (identifierMessageTypeMapping.ContainsKey(identifier)) { Type messageTypesFromIdentifier = identifierMessageTypeMapping[identifier]; foreach (var listener in listeners) { DiagnosticsEvent writableEvent = new DiagnosticsEvent(identifier, messageType, metaIdentifier, message, exception); listener.Write(writableEvent); } } }

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• Dynamically Run IQueryable Method

  - by Micah

  Hi! I'm trying to run the Count() function of a Linq statement in an overriden Gridview function. Basically, I want to be able to assign a linq query to a gridview, and on the OnDataBound(e) event in my new extended gridview have it retrieve the count, using the IQueryable. This is where I'm at so far: protected override void OnDataBound(EventArgs e) { IEnumerable _data = null; if (this.DataSource is IQueryable) { _data = (IQueryable)this.DataSource; } System.Type dataSourceType = _data.GetType(); System.Type dataItemType = typeof(object); if (dataSourceType.HasElementType) { dataItemType = dataSourceType.GetElementType(); } else if (dataSourceType.IsGenericType) { dataItemType = dataSourceType.GetGenericArguments()[0]; } else if (_data is IEnumerable) { IEnumerator dataEnumerator = _data.GetEnumerator(); if (dataEnumerator.MoveNext() && dataEnumerator.Current != null) { dataItemType = dataEnumerator.Current.GetType(); } } Object o = Activator.CreateInstance(dataItemType); object[] objArray = new object[] { o }; RowCount = (int)dataSourceType.GetMethod("Count").Invoke(_data, objArray); Any ideas? I'm really new with working with IQueryables and Linq so I may be way off. How can I get my _data to allow me to run the Count function?

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