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  • Substrings, timer and LED lights, as3

    - by VideoDnd
    How would I sync my timer with my LED lights? I don't understand how to to set up the strings and conditions, so that they are unique to each number space. Need a condition and values for each blinker var condition:Number = 5; if(condition==5){ blink.visible = !blink.visible; //blink_.visible = !box.visible; //blink__.visible = !box.visible; } } Complete code //MY TIMER var timer:Timer = new Timer(100); //INTEGER VALUES var count:int = 0; var fcount:int = 0; var oldcount:int = 0; //FORMATTING STRING function formatCount(i:int):String { var fraction:int = i % 100; var whole:int = i / 100; return ("00" + whole).substr(-2, 2) + "." + (fraction < 10 ? "0" + fraction : fraction); } //START TIMER timer.start(); timer.addEventListener(TimerEvent.TIMER, condition); //ANIMATION function condition(event:TimerEvent):void{ count++; fcount=int(count) var toText:String = formatCount(fcount); dec.text = toText.substr(4, 1); decimal.text = toText.substr(3, 1); ones.text = toText.substr(1, 1); //LED LIGHTS var condition:Number = 5; if(condition==5){ blink.visible = !blink.visible; //blink_.visible = !box.visible; //blink__.visible = !box.visible; } }

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  • Why does a sub-class class of a class have to be static in order to initialize the sub-class in the

    - by Alex
    So, the question is more or less as I wrote. I understand that it's probably not clear at all so I'll give an example. I have class Tree and in it there is the class Node, and the empty constructor of Tree is written: public class RBTree { private RBNode head; public RBTree(RBNode head,RBTree leftT,RBTree rightT){ this.head=head; this.head.leftT.head.father = head; this.head.rightT.head.father = head; } public RBTree(RBNode head){ this(head,new RBTree(),new RBTree()); } public RBTree(){ this(new RBNode(),null,null); } public class RBNode{ private int value; private boolean isBlack; private RBNode father; private RBTree leftT; private RBTree rightT; } } Eclipse gives me the error: "No enclosing instance of type RBTree is available due to some intermediate constructor invocation" for the "new RBTree()" in the empty constructor. However, if I change the RBNode to be a static class, there is no problem. So why is it working when the class is static. BTW, I found an easy solution for the cunstructor: public RBTree(){ this.head = new RBNode(); } So, I have no idea what is the problem in the first piece of code.

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  • MSSQL in ASP.NET application getting unstable after a certain period

    - by Barslett
    Hello, I have an ASP.NET 2.0 application that I made to keep track of disruption reports about our public transport system. The architecture is pretty straight-forward; an MSSQL Express 2008 database, ADO.NET and a DataSet/DAL with a few methods to access the database. There is a set of .aspx pages for the UI in use by our dispatchers and on our public website, as well as a set of SOAP and REST webservices and an RSS feed. Everything worked just fine for more than a year, until two weeks ago. Now and then, it seems as the database enters an unstable mode, and the application starts responding something right, something wrong. The typical error is that apparently, an empty DataTable is returned to the public disruption overview or to the RSS generator. Thus, the user gets e.g. an empty GridView, but no exception is thrown AFAIK, and nothing is written to the Windows Application log. After a restart of the MSSQL Express service, the situation is back to normal. It has to be said that the situation first time appeared a few days after I made a new minor upgrade of the application. The RSS generator was slightly rewritten, and I added a WCF REST service. But the DAL and the database schema were untouched... Any hints of how we could keep the database stable? It is a bit annoying not to have a clue ;-)

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  • Why does TrimStart trims a char more when asked to trim "PRN.NUL" ?

    - by James
    Here is the code: namespace TrimTest { class Program { static void Main(string[] args) { string ToTrim = "PRN.NUL"; Console.WriteLine(ToTrim); string Trimmed = ToTrim.TrimStart("PRN.".ToCharArray()); Console.WriteLine(Trimmed); ToTrim = "PRN.AUX"; Console.WriteLine(ToTrim); Trimmed = ToTrim.TrimStart("PRN.".ToCharArray()); Console.WriteLine(Trimmed); ToTrim = "AUX.NUL"; Console.WriteLine(ToTrim); Trimmed = ToTrim.TrimStart("AUX.".ToCharArray()); Console.WriteLine(Trimmed); } } } The output is like this: PRN.NUL UL PRN.AUX AUX AUX.NUL NUL As you can see, the TrimStart took out the N from NUL. But it doesn't do that for other strings even if it started with PRN. I tried with .NET Framework 3.5 and 4.0 and the results are same. Are there any explanation on what causes this behavior?

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  • std::list : get next element

    - by sheepsimulator
    I'm trying to build a string using data elements stored in a std::list, where I want commas placed only between the elements (ie, if elements are {A,B,C,D} in list, result string should be "A,B,C,D". This code does not work: typedef std::list< shared_ptr<EventDataItem> > DataItemList; // ... std::string Compose(DataItemList& dilList) { std::stringstream ssDataSegment; for(iterItems = dilList.begin(); iterItems = dilList.end(); iterItems++) { // Lookahead in list to see if next element is end if((iterItems + 1) == dilList.end()) { ssDataSegment << (*iterItems)->ToString(); } else { ssDataSegment << (*iterItems)->ToString() << ","; } } return ssDataSegment.str(); } How do I get at "the-next-item" in a std::list using an iterator? I would expect that it's a linked-list, why can't I get at the next item?

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  • How to implement generic callbacks in C++

    - by Kylotan
    Forgive my ignorance in asking this basic question but I've become so used to using Python where this sort of thing is trivial that I've completely forgotten how I would attempt this in C++. I want to be able to pass a callback to a function that performs a slow process in the background, and have it called later when the process is complete. This callback could be a free function, a static function, or a member function. I'd also like to be able to inject some arbitrary arguments in there for context. (ie. Implementing a very poor man's coroutine, in a way.) On top of that, this function will always take a std::string, which is the output of the process. I don't mind if the position of this argument in the final callback parameter list is fixed. I get the feeling that the answer will involve boost::bind and boost::function but I can't work out the precise invocations that would be necessary in order to create arbitrary callables (while currying them to just take a single string), store them in the background process, and invoke the callable correctly with the string parameter.

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  • "Order By" in LINQ-to-SQL Causes performance issues

    - by panamack
    I've set out to write a method in my C# application which can return an ordered subset of names from a table containing about 2000 names starting at the 100th name and returning the next 20 names. I'm doing this so I can populate a WPF DataGrid in my UI and do some custom paging. I've been using LINQ to SQL but hit a snag with this long executing query so I'm examining the SQL the LINQ query is using (Query B below). Query A runs well: SELECT TOP (20) [t0].[subject_id] AS [Subject_id], [t0].[session_id] AS [Session_id], [t0].[name] AS [Name] FROM [Subjects] AS [t0] WHERE (NOT (EXISTS( SELECT NULL AS [EMPTY] FROM ( SELECT TOP (100) [t1].[subject_id] FROM [Subjects] AS [t1] WHERE [t1].[session_id] = 1 ORDER BY [t1].[name] ) AS [t2] WHERE [t0].[subject_id] = [t2].[subject_id] ))) AND ([t0].[session_id] = 1) Query B takes 40 seconds: SELECT TOP (20) [t0].[subject_id] AS [Subject_id], [t0].[session_id] AS [Session_id], [t0].[name] AS [Name] FROM [Subjects] AS [t0] WHERE (NOT (EXISTS( SELECT NULL AS [EMPTY] FROM ( SELECT TOP (100) [t1].[subject_id] FROM [Subjects] AS [t1] WHERE [t1].[session_id] = 1 ORDER BY [t1].[name] ) AS [t2] WHERE [t0].[subject_id] = [t2].[subject_id] ))) AND ([t0].[session_id] = 1) ORDER BY [t0].[name] When I add the ORDER BY [t0].[name] to the outer query it slows down the query. How can I improve the second query? This was my LINQ stuff Nick int sessionId = 1; int start = 100; int count = 20; // Query subjects with the shoot's session id var subjects = cldb.Subjects.Where<Subject>(s => s.Session_id == sessionId); // Filter as per params var orderedSubjects = subjects .OrderBy<Subject, string>( s => s.Col_zero ); var filteredSubjects = orderedSubjects .Skip<Subject>(start) .Take<Subject>(count);

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  • Why Illegal cookies are send by Browser and received by web servers (rfc2109)?

    - by Artyom
    Hello, According to RFC 2109 cookie's value can be either HTTP token or quoted string, and token can't include non-ASCII characters. Cookie's RFC 2109: http://tools.ietf.org/html/rfc2109#page-3 HTTP's RFC 2068 token definition: http://tools.ietf.org/html/rfc2068#page-16 However I had found that Firefox browser (3.0.6) sends cookies with utf-8 string as-is and three web servers I tested (apache2, lighttpd, nginx) pass this string as-is to the application. For example, raw request from browser: $ nc -l -p 8080 GET /hello HTTP/1.1 Host: localhost:8080 User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.9) Gecko/2009050519 Firefox/2.0.0.13 (Debian-3.0.6-1) Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: windows-1255,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive Cookie: wikipp=1234; wikipp_username=?????? Cache-Control: max-age=0 And raw response of apache, nginx and lighttpd HTTP_COOKIE CGI variable: wikipp=1234; wikipp_username=?????? What do I miss? Can somebody explain me?

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  • How to remove the MenuBar of an application using windows API ?

    - by karthik
    I am using the below code to remove the Title Bar of an application, which is working perfectly for notepad. Now i want to remove the Menu Bar also. How to achieve it ? //Finds a window by class name [DllImport("USER32.DLL")] public static extern IntPtr FindWindow(string lpClassName, string lpWindowName); //Sets a window to be a child window of another window [DllImport("USER32.DLL")] public static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent); //Sets window attributes [DllImport("USER32.DLL")] public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong); //Gets window attributes [DllImport("USER32.DLL")] public static extern int GetWindowLong(IntPtr hWnd, int nIndex); [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)] static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName); //assorted constants needed public static int GWL_STYLE = -16; public static int WS_BORDER = 0x00800000; //window with border public static int WS_DLGFRAME = 0x00400000; //window with double border but no title public static int WS_CAPTION = WS_BORDER | WS_DLGFRAME; //window with a title bar public void WindowsReStyle() { Process[] Procs = Process.GetProcesses(); foreach (Process proc in Procs) { if (proc.ProcessName.StartsWith("notepad")) { IntPtr pFoundWindow = proc.MainWindowHandle; int style = GetWindowLong(pFoundWindow, GWL_STYLE); SetWindowLong(pFoundWindow, GWL_STYLE, (style & ~WS_CAPTION)); } } }

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  • What's the most DRY-appropriate way to execute an SQL command?

    - by Sean U
    I'm looking to figure out the best way to execute a database query using the least amount of boilerplate code. The method suggested in the SqlCommand documentation: private static void ReadOrderData(string connectionString) { string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;"; using (SqlConnection connection = new SqlConnection(connectionString)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); try { while (reader.Read()) { Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1])); } } finally { reader.Close(); } } } mostly consists of code that would have to be repeated in every method that interacts with the database. I'm already in the habit of factoring out the establishment of a connection, which would yield code more like the following. (I'm also modifying it so that it returns data, in order to make the example a bit less trivial.) private SQLConnection CreateConnection() { var connection = new SqlConnection(_connectionString); connection.Open(); return connection; } private List<int> ReadOrderData() { using(var connection = CreateConnection()) using(var command = connection.CreateCommand()) { command.CommandText = "SELECT OrderID FROM dbo.Orders;"; using(var reader = command.ExecuteReader()) { var results = new List<int>(); while(reader.Read()) results.Add(reader.GetInt32(0)); return results; } } } That's an improvement, but there's still enough boilerplate to nag at me. Can this be reduced further? In particular, I'd like to do something about the first two lines of the procedure. I don't feel like the method should be in charge of creating the SqlCommand. It's a tiny piece of repetition as it is in the example, but it seems to grow if transactions are being managed manually or timeouts are being altered or anything like that.

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  • How to clean completly select2 control?

    - by Candil
    I'm working with the awesome select2 control. I'm trying to clean and disable the select2 with the content too so I do this: $("#select2id").empty(); $("#select2id").select2("disable"); Ok, it works, but if i had a value selected all the items are removed, the control is disabled, but the selected value is still displayed. I want to clear all content so the placeholder would be showed. Here is a example I did where you can see the issue: http://jsfiddle.net/BSEXM/ HTML: <select id="sel" data-placeholder="This is my placeholder"> <option></option> <option value="a">hello</option> <option value="b">all</option> <option value="c">stack</option> <option value="c">overflow</option> </select> <br> <button id="pres">Disable and clear</button> <button id="ena">Enable</button> Code: $(document).ready(function () { $("#sel").select2(); $("#pres").click(function () { $("#sel").empty(); $("#sel").select2("disable"); }); $("#ena").click(function () { $("#sel").select2("enable"); }); }); CSS: #sel { margin: 20px; } Do you have any idea or advice to this?

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  • Text piped to PowerShell.exe isn't recieved when using [Console]::ReadLine()

    - by crtracy
    I'm getting itermittent data loss when calling .NET [Console]::ReadLine() to read piped input to PowerShell.exe: >ping localhost | powershell -NonInteractive -NoProfile -C "do {$line = [Console]::ReadLine(); ('' + (Get-Date -f 'HH:mm :ss') + $line) | Write-Host; } while ($line -ne $null)" 23:56:45time<1ms 23:56:45 23:56:46time<1ms 23:56:46 23:56:47time<1ms 23:56:47 23:56:47 Normally 'ping localhost' from Vista64 looks like this, so there is a lot of data missing from the output above: Pinging WORLNTEC02.bnysecurities.corp.local [::1] from ::1 with 32 bytes of data: Reply from ::1: time<1ms Reply from ::1: time<1ms Reply from ::1: time<1ms Reply from ::1: time<1ms Ping statistics for ::1: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms But using the same API from C# recieves all the data sent to the process (excluding some newline differences). Code: namespace ConOutTime { class Program { static void Main (string[] args) { string s; while ((s = Console.ReadLine ()) != null) { if (s.Length > 0) // don't write time for empty lines Console.WriteLine("{0:HH:mm:ss} {1}", DateTime.Now, s); } } } } Output: 00:44:30 Pinging WORLNTEC02.bnysecurities.corp.local [::1] from ::1 with 32 bytes of data: 00:44:30 Reply from ::1: time<1ms 00:44:31 Reply from ::1: time<1ms 00:44:32 Reply from ::1: time<1ms 00:44:33 Reply from ::1: time<1ms 00:44:33 Ping statistics for ::1: 00:44:33 Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), 00:44:33 Approximate round trip times in milli-seconds: 00:44:33 Minimum = 0ms, Maximum = 0ms, Average = 0ms So, if calling the same API from PowerShell instead of C# many parts of StdIn get 'eaten'. Is the PowerShell host reading string from StdIn even though I didn't use 'PowerShell.exe -Command -'?

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  • php.ini on goDaddy

    - by Afrosimon
    Hey all, I've got a little problem on a goDaddy server. I have a php script (ajaxCRUD) in which there's an upload field, and I can't get it to accept file over the default limit. I always get this (when I output the $_FILE[$fieldname]) : array(5) { ["name"]=> string(13) "children2.mp3" ["type"]=> string(0) "" ["tmp_name"]=> string(0) "" ["error"]=> int(1) ["size"]=> int(0) } Things I tried : Added a parameter in the HTML form ([...]name="MAX_FILE_SIZE" value="10000000"[...]) Changed the php5.ini at the root of the server, to no avail. After a phpinfo(), no differences are seen, even though the phpinfo clearly indicate it is reading the same php5.ini : [...]/html/php5.ini. Here is what I added in this file : upload_tmp_dir = ./temp upload_max_filesize = 20M Anything under 2M (the default value) is okay, so there's no problem with the upload path or file permission. I don't have any more idea for the moment, do any of you has one?

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  • Boost binding a function taking a reference

    - by Jamie Cook
    Hi all, I am having problems compiling the following snippet int temp; vector<int> origins; vector<string> originTokens = OTUtils::tokenize(buffer, ","); // buffer is a char[] array // original loop BOOST_FOREACH(string s, originTokens) { from_string(temp, s); origins.push_back(temp); } // I'd like to use this to replace the above loop std::transform(originTokens.begin(), originTokens.end(), origins.begin(), boost::bind<int>(&FromString<int>, boost::ref(temp), _1)); where the function in question is // the third parameter should be one of std::hex, std::dec or std::oct template <class T> bool FromString(T& t, const std::string& s, std::ios_base& (*f)(std::ios_base&) = std::dec) { std::istringstream iss(s); return !(iss >> f >> t).fail(); } the error I get is 1>Compiling with Intel(R) C++ 11.0.074 [IA-32]... (Intel C++ Environment) 1>C:\projects\svn\bdk\Source\deps\boost_1_42_0\boost/bind/bind.hpp(303): internal error: assertion failed: copy_default_arg_expr: rout NULL, no error (shared/edgcpfe/il.c, line 13919) 1> 1> return unwrapper<F>::unwrap(f, 0)(a[base_type::a1_], a[base_type::a2_]); 1> ^ 1> 1>icl: error #10298: problem during post processing of parallel object compilation Google is being unusually unhelpful so I hope that some one here can provide some insights.

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  • Background color remaining when switching views

    - by Guy
    Hi Guys. I have a UIViewController named equationVC who's user interface is being programmatically created from another NSObject class called equationCon. Upon loading equationVC, a method called chooseInterface is called from the equationCon class. I have a global variable (globalVar) that points to a user defined string. chooseInterface finds a method in the equationCon class that matches the string globalVar points to. In this case, let's say that globalVar points to a string that is called "methodThatMatches." In methodThatMatches, another view controller needs to show the results of what methodThatMatches did. methodThatMatches creates a new equationVC that calls upon methodThatMatches2. As a test, each method changes the color of the background. When the application starts up, I get a purple background, but as soon as I hit backwards I get another purple screen, which should be yellow. I do not think that I am release the view properly. Can anyone help? -(void)chooseInterface { NSString* equationTemp = [globalVar stringByReplacingOccurrencesOfString:@" " withString:@""]; equationTemp = [equationTemp stringByReplacingOccurrencesOfString:@"'" withString:@""]; SEL equationName = NSSelectorFromString(equationTemp); NSLog(@"selector! %@",NSStringFromSelector(equationName)); if([self respondsToSelector:equationName]){ [self performSelector:equationName]; } } -(void)methodThatMatches{ self.equationVC.view.backgroundColor = [UIColor yellowColor]; [setGlobalVar:@"methodThatMatches2"]; EquationVC* temp = [[EquationVC alloc] init]; [[self.equationVC navigationController] pushViewController:temp animated:YES ]; [temp release]; } -(void)methodThatmatches2{ self.equationVC.view.backgroundColor = [UIColor purpleColor]; }

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  • How do I create a hyperlink in java?

    - by Justin984
    I'm going through the google app engine tutorials at https://developers.google.com/appengine/docs/java/gettingstarted/usingusers I'm very new to google app engine, java and web programming in general. So my question is, at the bottom of the page it says to add a link to allow the user to log out. So far I've got this: public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { UserService userService = UserServiceFactory.getUserService(); User user = userService.getCurrentUser(); if(user != null){ resp.setContentType("text/plain"); resp.getWriter().println("Hello, " + user.getNickname()); String logoutLink = String.format("<a href=\"%s\">Click here to log out.</a>", userService.createLogoutURL(req.getRequestURI())); resp.getWriter().println(logoutLink); }else { resp.sendRedirect(userService.createLoginURL(req.getRequestURI())); } } However instead of a link, the full string is printed to the screen including the tags. When I look at the page source, I have no tags or any of the other stuff that goes with a webpage. I guess that makes sense considering I've done nothing to output any of that. Do I just do a bunch of resp.GetWriter().println() statements to output the rest of the webpage, or is there something else I don't know about? Thanks!

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  • data transmission between two sites

    - by SaMSa
    I'm use Asp.Net Mvc 4 www.hostname.com to my site from my report.hostname2.com send and receive data to move directly to that address by the string bi codebehind. querysstring not, because sending a very long string I mean rapor.coskunoglu.net/Pdf address to send string data to move directly to that address PDF of the screen to make it appear so. How can I do this? Thank you, take it easy. I'm sorry, my english is not good. EDIT: I want to use POST. sb - my StringBuilder. byte[] bytt = Encoding.UTF8.GetBytes(sb.ToString()); WebRequest wr = WebRequest.Create("http://report.hostname2.com/Pdf"); wr.ContentType = "application/x-www-form-urlencoded"; wr.ContentLength = bytt.Length; wr.Method = "POST"; Stream st = wr.GetRequestStream(); st.Write(bytt, 0, bytt.Length); st.Close(); After you send the POST I want to go to report.hostname2.com. Did you see this my job?

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  • __toString magic and type coercion

    - by TomcatExodus
    I've created a Template class for managing views and their associated data. It implements Iterator and ArrayAccess, and permits "sub-templates" for easy usage like so: <p><?php echo $template['foo']; ?></p> <?php foreach($template->post as $post): ?> <p><?php echo $post['bar']; ?></p> <?php endforeach; ?> Anyways, rather than using inline core functions, such as hash() or date(), I figured it would be useful to create a class called TemplateData, which would act as a wrapper for any data stored in the templates. This way, I can add a list of common methods for formatting, for example: echo $template['foo']->asCase('upper'); echo $template['bar']->asDate('H:i:s'); //etc.. When a value is set via $template['foo'] = 'bar'; in the controllers, the value of 'bar' is stored in it's own TemplateData object. I've used the magic __toString() so when you echo a TemplateData object, it casts to (string) and dumps it's value. However, despite the mantra controllers and views should not modify data, whenever I do something like this: $template['foo'] = 1; echo $template['foo'] + 1; //exception It dies on a Object of class TemplateData could not be converted to int; Unless I recast $template['foo'] to a string: echo ((string) $template['foo']) + 1; //outputs 2 Sort of defeats the purpose having to jump through that hoop. Are there any workarounds for this sort of behavior that exist, or should I just take this as it is, an incidental prevention of data modification in views?

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  • Test MVC using moq

    - by Raminder
    I am new to moq and I was trying to test a controller (MVC) behaviour that when the view raises a certain event, controller calls a certain function on model, here are the classes - public class Model { public void CalculateAverage() { ... } ... } public class View { public event EventHandler CalculateAverage; private void RaiseCalculateAverage() { if (CalculateAverage != null) { CalculateAverage(this, EventArgs.Empty); } } ... } public class Controller { private Model model; private View view; public Controller(Model model, View view) { this.model = model this.view = view; view.CalculaeAverage += view_CalculateAverage; } priavate void view_CalculateAverage(object sender, EventArgs args) { model.CalculateAverage(); } } and the test - [Test] public void ModelCalculateAverageCalled() { Mock<Model> modelMock = new Mock<Model>(); Mock<View> viewMock = new Mock<View>(); Controller controller = new Controller(modelMock.Object, viewMock.Object); viewMock.Raise(x => x.CalculateAverage += null, new EventArgs.Empty); modelMock.Verify(x => x.CalculateAverage()); //never comes here, test fails in above line and exits Assert.True(true); } The issue is that the test is failing in the second last line with "Invocation was not performed on the mock: x = x.CalculateAverage()". Another thing I noticed is that the test terminates on this second last line and the last line is never executed. Am I doing everything correct?

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  • The mathematics of Schellings segregation model

    - by Bruce
    For those who don't know the model. You can read this pdf. I want to find what is the probability that 2 nodes are each others neighbors when the algorithm converges (i.e. when all nodes are happy). Here's the model in a gist. You have a grid (say 10x10). You have nodes of two kind (red and green) 45 each. So we have 10 empty spaces. We randomly place the nodes on the grid. Now we scan through this grid (Exact order does not matter according to Schelling). Each node wants a specific percentage of people of same kind in its Moore neighborhood (say b = 50% for each red and green). We calculate the happiness of each node (a = Number of neighbors of same kind/Number of neighbors of different kind). If a node is unhappy (a < b) it moves to an empty cell where it knows it will be happy. This movement can change the dynamics of old as well as new neighborhood. Algorithm converges when all nodes are happy. PS - I am looking for links for any mathematical analysis of the Schelling's model.

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  • How to display objects with dynamic fields in wpf data grid?

    - by Oliver Hanappi
    Hi! I want to display and edit some objects in a WPF data grid and I'm looking for a good way to do so. All objects I want to display have the same fields, but every execution the fields of my objects can differ. Here is a piece of the interface to illustrate what I mean: public interface IMyObject { IEnumerable<string> GetFieldNames(); IEnumerable<Type> GetFieldTypes(); object GetField(string name); void SetField(string name, object value); } How can I generate a data grid which displays this kind of objects? I thought of XAML generation to define the columns, but I'm still facing the problem of accessing the fields. I think I could realize this with value converters, another option would be to dynamically create a type which exposes the dynamic fields with properties. Are there any other ways and which should I favor? I'm keen on hearing your opinions. Best Regards, Oliver Hanappi

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  • How do I rewrite a for loop with a shared dependency using actors

    - by Thomas Rynne
    We have some code which needs to run faster. Its already profiled so we would like to make use of multiple threads. Usually I would setup an in memory queue, and have a number of threads taking jobs of the queue and calculating the results. For the shared data I would use a ConcurrentHashMap or similar. I don't really want to go down that route again. From what I have read using actors will result in cleaner code and if I use akka migrating to more than 1 jvm should be easier. Is that true? However, I don't know how to think in actors so I am not sure where to start. To give a better idea of the problem here is some sample code: case class Trade(price:Double, volume:Int, stock:String) { def value(priceCalculator:PriceCalculator) = (priceCalculator.priceFor(stock)-> price)*volume } class PriceCalculator { def priceFor(stock:String) = { Thread.sleep(20)//a slow operation which can be cached 50.0 } } object ValueTrades { def valueAll(trades:List[Trade], priceCalculator:PriceCalculator):List[(Trade,Double)] = { trades.map { trade => (trade,trade.value(priceCalculator)) } } def main(args:Array[String]) { val trades = List( Trade(30.5, 10, "Foo"), Trade(30.5, 20, "Foo") //usually much longer ) val priceCalculator = new PriceCalculator val values = valueAll(trades, priceCalculator) } } I'd appreciate it if someone with experience using actors could suggest how this would map on to actors.

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  • HttpWebResonse hangs on multiple request

    - by Ehsan
    I've an application that create many web request to donwload the news pages of a web site (i've tested for many web sites) after a while I find out that the application slows down in fetching the html source then I found out that HttpWebResonse fails getting the response. I post only the function that do this job. public PageFetchResult Fetch() { PageFetchResult fetchResult = new PageFetchResult(); try { HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(URLAddress); HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); Uri requestedURI = new Uri(URLAddress); Uri responseURI = resp.ResponseUri; if (Uri.Equals(requestedURI, responseURI)) { string resultHTML = ""; byte[] reqHTML = ResponseAsBytes(resp); if (!string.IsNullOrEmpty(FetchingEncoding)) resultHTML = Encoding.GetEncoding(FetchingEncoding).GetString(reqHTML); else if (!string.IsNullOrEmpty(resp.CharacterSet)) resultHTML = Encoding.GetEncoding(resp.CharacterSet).GetString(reqHTML); resp.Close(); fetchResult.IsOK = true; fetchResult.ResultHTML = resultHTML; } else { URLAddress = responseURI.AbsoluteUri; relayPageCount++; if (relayPageCount > 5) { fetchResult.IsOK = false; fetchResult.ErrorMessage = "Maximum page redirection occured."; return fetchResult; } return Fetch(); } } catch (Exception ex) { fetchResult.IsOK = false; fetchResult.ErrorMessage = ex.Message; } return fetchResult; } any solution would greatly appreciate

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  • Is it possible to defer member initialization to the constructor body?

    - by Kjir
    I have a class with an object as a member which doesn't have a default constructor. I'd like to initialize this member in the constructor, but it seems that in C++ I can't do that. Here is the class: #include <boost/asio.hpp> #include <boost/array.hpp> using boost::asio::ip::udp; template<class T> class udp_sock { public: udp_sock(std::string host, unsigned short port); private: boost::asio::io_service _io_service; udp::socket _sock; boost::array<T,256> _buf; }; template<class T> udp_sock<T>::udp_sock(std::string host = "localhost", unsigned short port = 50000) { udp::resolver res(_io_service); udp::resolver::query query(udp::v4(), host, "spec"); udp::endpoint ep = *res.resolve(query); ep.port(port); _sock(_io_service, ep); } The compiler tells me basically that it can't find a default constructor for udp::socket and by my research I understood that C++ implicitly initializes every member before calling the constructor. Is there any way to do it the way I wanted to do it, or is it too "Java-oriented" and not feasible in C++? I worked around the problem by defining my constructor like this: template<class T> udp_sock<T>::udp_sock(std::string host = "localhost", unsigned short port = 50000) : _sock(_io_service) { udp::resolver res(_io_service); udp::resolver::query query(udp::v4(), host, "spec"); udp::endpoint ep = *res.resolve(query); ep.port(port); _sock.bind(ep); } So my question is more out of curiosity and to better understand OOP in C++

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  • Fluent NHibernate - Delete a related object when no explicit relationship exists in the model

    - by John Price
    I've got an application that keeps track of (for the sake of an example) what drinks are available at a given restaurant. My domain model looks like: class Restaurant { public IEnumerable<RestaurantDrink> GetRestaurantDrinks() { ... } //other various properties } class RestaurantDrink { public Restaurant Restaurant { get; set; } public Drink { get; set; } public string DrinkVariety { get; set; } //"fountain drink", "bottled", etc. //other various properties } class Drink { public string Name { get; set; } public string Manufacturer { get; set; } //other various properties } My db schema is (I hope) about what you'd expect; "RestaurantDrinks" is essentially a mapping table between Restaurants and Drinks with some extra properties (like "DrinkVariety" tacked on). Using Fluent NHibernate to set up mappings, I've set up a "HasMany" relationship from Restaurants to RestaurantDrinks that causes the latter to be deleted when its parent Restaurant is deleted. My question is, given that "Drink" does not have any property on it that explicitly references RestaurantDrinks (the relationship only exists in the underlying database), can I set up a mapping that will cause RestaurantDrinks to be deleted if their associated Drink is deleted?

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