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  • Why doesn't my form post when I disable the submit button to prevent double clicking?

    - by John MacIntyre
    Like every other web developer on the planet, I have an issue with users double clicking the submit button on my forms. My understanding is that the conventional way to handle this issue, is to disable the button immediately after the first click, however when I do this, it doesn't post. I did do some research on this, god knows there's enough information, but other questions like Disable button on form submission, disabling the button appears to work. The original poster of Disable button after submit appears to have had the same problem as me, but there is no mention on how/if he resolved it. Here's some code on how to repeat it (tested in IE8 Beta2, but had same problem in IE7) My aspx code <%@ Page Language="C#" CodeFile="Default.aspx.cs" Inherits="_Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <script language="javascript" type="text/javascript"> function btn_onClick() { var chk = document.getElementById("chk"); if(chk.checked) { var btn = document.getElementById("btn"); btn.disabled = true; } } </script> <body> <form id="form1" runat="server"> <asp:Literal ID="lit" Text="--:--:--" runat="server" /> <br /> <asp:Button ID="btn" Text="Submit" runat="server" /> <br /> <input type="checkbox" id="chk" />Disable button on first click </form> </body> </html> My cs code using System; public partial class _Default : System.Web.UI.Page { protected override void OnInit(EventArgs e) { base.OnInit(e); btn.Click += new EventHandler(btn_Click); btn.OnClientClick = "btn_onClick();"; } void btn_Click(object sender, EventArgs e) { lit.Text = DateTime.Now.ToString("HH:mm:ss"); } } Notice that when you click the button, a postback occurs, and the time is updated. But when you check the check box, the next time you click the button, the button is disabled (as expected), but never does the postback. WHAT THE HECK AM I MISSING HERE??? Thanks in advance.

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  • Memory efficient int-int dict in Python

    - by Bolo
    Hi, I need a memory efficient int-int dict in Python that would support the following operations in O(log n) time: d[k] = v # replace if present v = d[k] # None or a negative number if not present I need to hold ~250M pairs, so it really has to be tight. Do you happen to know a suitable implementation (Python 2.7)? EDIT Removed impossible requirement and other nonsense. Thanks, Craig and Kylotan! To rephrase. Here's a trivial int-int dictionary with 1M pairs: >>> import random, sys >>> from guppy import hpy >>> h = hpy() >>> h.setrelheap() >>> d = {} >>> for _ in xrange(1000000): ... d[random.randint(0, sys.maxint)] = random.randint(0, sys.maxint) ... >>> h.heap() Partition of a set of 1999530 objects. Total size = 49161112 bytes. Index Count % Size % Cumulative % Kind (class / dict of class) 0 1 0 25165960 51 25165960 51 dict (no owner) 1 1999521 100 23994252 49 49160212 100 int On average, a pair of integers uses 49 bytes. Here's an array of 2M integers: >>> import array, random, sys >>> from guppy import hpy >>> h = hpy() >>> h.setrelheap() >>> a = array.array('i') >>> for _ in xrange(2000000): ... a.append(random.randint(0, sys.maxint)) ... >>> h.heap() Partition of a set of 14 objects. Total size = 8001108 bytes. Index Count % Size % Cumulative % Kind (class / dict of class) 0 1 7 8000028 100 8000028 100 array.array On average, a pair of integers uses 8 bytes. I accept that 8 bytes/pair in a dictionary is rather hard to achieve in general. Rephrased question: is there a memory-efficient implementation of int-int dictionary that uses considerably less than 49 bytes/pair?

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  • ArithmeticException thrown during BigDecimal.divide

    - by polygenelubricants
    I thought java.math.BigDecimal is supposed to be The Answer™ to the need of performing infinite precision arithmetic with decimal numbers. Consider the following snippet: import java.math.BigDecimal; //... final BigDecimal one = BigDecimal.ONE; final BigDecimal three = BigDecimal.valueOf(3); final BigDecimal third = one.divide(three); assert third.multiply(three).equals(one); // this should pass, right? I expect the assert to pass, but in fact the execution doesn't even get there: one.divide(three) causes ArithmeticException to be thrown! Exception in thread "main" java.lang.ArithmeticException: Non-terminating decimal expansion; no exact representable decimal result. at java.math.BigDecimal.divide It turns out that this behavior is explicitly documented in the API: In the case of divide, the exact quotient could have an infinitely long decimal expansion; for example, 1 divided by 3. If the quotient has a non-terminating decimal expansion and the operation is specified to return an exact result, an ArithmeticException is thrown. Otherwise, the exact result of the division is returned, as done for other operations. Browsing around the API further, one finds that in fact there are various overloads of divide that performs inexact division, i.e.: final BigDecimal third = one.divide(three, 33, RoundingMode.DOWN); System.out.println(three.multiply(third)); // prints "0.999999999999999999999999999999999" Of course, the obvious question now is "What's the point???". I thought BigDecimal is the solution when we need exact arithmetic, e.g. for financial calculations. If we can't even divide exactly, then how useful can this be? Does it actually serve a general purpose, or is it only useful in a very niche application where you fortunately just don't need to divide at all? If this is not the right answer, what CAN we use for exact division in financial calculation? (I mean, I don't have a finance major, but they still use division, right???).

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  • Writing to a comet stream using tomcat 6.0

    - by user301247
    Hey I'm new to java servlets and I am trying to write one that uses comet so that I can create a long polling Ajax request. I can successfully start the stream and perform operations but I can't write anything out. Here is my code: public class CometTestServlet extends HttpServlet implements CometProcessor { /** * */ private static final long serialVersionUID = 1070949541963627977L; private MessageSender messageSender = null; protected ArrayList<HttpServletResponse> connections = new ArrayList<HttpServletResponse>(); public void event(CometEvent cometEvent) throws IOException, ServletException { HttpServletRequest request = cometEvent.getHttpServletRequest(); HttpServletResponse response = cometEvent.getHttpServletResponse(); //final PrintWriter out = response.getWriter(); if (cometEvent.getEventType() == CometEvent.EventType.BEGIN) { PrintWriter writer = response.getWriter(); writer.println("<!doctype html public \"-//w3c//dtd html 4.0 transitional//en\">"); writer.println("<head><title>JSP Chat</title></head><body bgcolor=\"#FFFFFF\">"); writer.println("</body></html>"); writer.flush(); cometEvent.setTimeout(10 * 1000); //cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.ERROR) { log("Error for session: " + request.getSession(true).getId()); synchronized(connections) { connections.remove(response); } cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.END) { log("End for session: " + request.getSession(true).getId()); synchronized(connections) { connections.remove(response); } PrintWriter writer = response.getWriter(); writer.println("</body></html>"); cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.READ) { //handleReadEvent(cometEvent); InputStream is = request.getInputStream(); byte[] buf = new byte[512]; do { int n = is.read(buf); //can throw an IOException if (n > 0) { log("Read " + n + " bytes: " + new String(buf, 0, n) + " for session: " + request.getSession(true).getId()); } else if (n < 0) { //error(cometEvent, request, response); return; } } while (is.available() > 0); } } Any help would be appreciated.

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  • Exception: attempt to acquire a reference on a close SQLiteClosable

    - by CommonsWare
    I posted this back in May on the [android-developers] Google Group. I never heard back and was not able to reproduce the problem until one of my students did last week. I figured I'd post it here and see if it rang any bells for anyone. In one of my code samples, I have the following method: static Cursor getAll(SQLiteDatabase db, String orderBy) { return(db.rawQuery("SELECT * FROM restaurants "+orderBy, null)); } When I run it, sporadically, I get this: 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): java.lang.IllegalStateException: attempt to acquire a reference on a close SQLiteClosable 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:31) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:56) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1118) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1092) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at apt.tutorial.Restaurant.getAll(Restaurant.java:14) This makes no sense to me. The database is definitely open. The SQLiteClosable is the SQLiteQuery created by SQLiteQueryDriver, and I see no evidence that there is an object pool or something going on here that might explain how a "new" SQLiteClosable is already closed. The fact that it is sporadic (meaning the same UI operations sometimes trigger the exception, but not always) suggests some sort of pool, race condition, or something...but I'm not sure where. Thoughts? Thanks! UPDATE: The code in question is from the LunchList tutorials out of my Android Programming Tutorials book. It's a bit spread out and not terribly suitable for posting directly in SO. You can download the code for that book from the above link if you want to take a look at it. I do not recall exactly which edition of the tutorial the student was working on at the time, though it was in the Tutorial 12-Tutorial 16 range. I was mostly hoping to run across somebody who had tripped over this problem before and had a likely culprit. I'm fairly certain my database is open. Thanks again!

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  • Sanity Check: change event not firing first time using keyboard

    - by macca1
    I've done a good amount of research on this and found a bunch of reported problems and solutions but the general consensus seems that all change problems in IE6 were fixed in jQuery 1.4.2. I'm having an issue where a change event is not firing in jQuery 1.4.2, but it did fire successfully in jQuery 1.3.2. This is in IE6. I'm about to submit a bug for this, but for my sanity I wanted to post it here first to see if there's something dumb I'm missing. I don't understand why this is working this way... <HTML> <HEAD> <TITLE>jQuery 1.4.2 Problem </TITLE> <script src="jquery-1.4.2.min.js" type="text/javascript"></script> <script> $(document).ready( function() { $("#firstBox").change(function() { alert("CHANGE"); }); // ONLOAD of document autofocus into the first element... $("form").find(":input:visible:first").focus() }); </script> </HEAD> <BODY> <form> <select id="firstBox"> <option value="" selected="selected">--</option> <option value="1">One</option> <option value="2">Two</option> </select> <br><br> <input size="10" id="secondBox"> </form> </BODY> </HTML> Simple enough, right? Onload of the page, give the first element focus. Onchange of the first element, alert. If you use the mouse, it works as expected. The page loads, the focus is in the drop down, you change the option, you get the alert. The problem is if you use the keyboard. The page loads, the focus is in the drop down, you press the down arrow. The option changes. Tab off the field, no alert. Weird. To make it even weirder, if you tab back into the field and change it again (all using the keyboard), the change event DOES fire after tab out this time. Any ideas?

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  • Display an Image using C# in Web Application

    - by Josh
    Hello again, I have a Web Application that I built a C# class in that generates a Report. This report takes nearly 40 seconds to generate because it searches hundreds of folders for certain files. So I was hoping there was a way to display a "Loading.." icon as this report is generating. I have a gif stored in my Images folder that would be perfect. The research that I've done at this point mostly talks about picturebox's and image controls that can hold the image but I was hoping there was just a way of displaying the image above the report while its being created. The Web Application is from a Web ADF Geocortex website and again I created a C# class that generates this report. Below is some code that may help. /// <summary> /// Generates HTML for the current report using the data in /// the given table. /// </summary> /// <param name="reportLayers">The layers to include in the report.</param> /// <returns> public override string GenerateReportHtml(List<ReportLayer> reportLayers) { StringBuilder htmlString = new StringBuilder(); StringWriter stringWriter = new StringWriter(htmlString); HtmlTextWriter writer = new HtmlTextWriter(stringWriter); string holdAPI = ""; List<string> exclusions = GetExcludedFields(); foreach (ReportLayer layer in reportLayers) { string[] strFiles = null; Boolean val = false; if (layer.Layer.Name == "Bottom Hole Location (OP)") writer.RenderBeginTag(HtmlTextWriterTag.P); // <p> writer.RenderBeginTag(HtmlTextWriterTag.Strong); // <strong> writer.Write(layer.Layer.Name); writer.RenderEndTag(); // end </strong> writer.RenderEndTag(); // end </p> writer.WriteBreak(); // <br /> foreach (ReportFeature feature in layer.ReportFeatures) { // each feature will be in a table writer.RenderBeginTag(HtmlTextWriterTag.Table); // <table> foreach (ReportField field in feature.ReportFields) { string fieldName = field.Alias; if (!exclusions.Contains(fieldName)) {

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  • How do I display a jquery dialog box before the entire page is loaded?

    - by obarshay
    On my site a number of operations can take a long time to complete. When I know a page will take a while to load, I would like to display a progress indicator while the page is loading. Ideally I would like to say something along the lines of: $("#dialog").show("progress.php"); and have that overlay on top of the page that is being loaded (disappearing after the operation is completed). Coding the progress bar and displaying progress is not an issue, the issue is getting a progress indicator to pop up WHILE the page is being loaded. I have been trying to use JQuery's dialogs for this but they only appear after the page is already loaded. This has to be a common problem but I am not familiar enough with JavaScript to know the best way to do this. Here's simple example to illustrate the problem. The code below fails to display the dialog box before the 20 second pause is up. I have tried in Chrome and Firefox. In fact I don't even see the "Please Wait..." text. Here's the code I am using: <html> <head> <link type="text/css" href="http://jqueryui.com/latest/themes/base/ui.all.css" rel="stylesheet" /> <script type="text/javascript" src="http://jqueryui.com/latest/jquery-1.3.2.js"></script> <script type="text/javascript" src="http://jqueryui.com/latest/ui/ui.core.js"></script> <script type="text/javascript" src="http://jqueryui.com/latest/ui/ui.dialog.js"></script> </head> <body> <div id="please-wait">My Dialog</div> <script type="text/javascript"> $("#please-wait").dialog(); </script> <?php flush(); echo "Waiting..."; sleep(20); ?> </body> </html>

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  • Overwhelmed by design patterns... where to begin?

    - by Pete
    I am writing a simple prototype code to demonstrate & profile I/O schemes (HDF4, HDF5, HDF5 using parallel IO, NetCDF, etc.) for a physics code. Since focus is on IO, the rest of the program is very simple: class Grid { public: floatArray x,y,z; }; class MyModel { public: MyModel(const int &nip1, const int &njp1, const int &nkp1, const int &numProcs); Grid grid; map<string, floatArray> plasmaVariables; }; Where floatArray is a simple class that lets me define arbitrary dimensioned arrays and do mathematical operations on them (i.e. x+y is point-wise addition). Of course, I could use better encapsulation (write accessors/setters, etc.), but that's not the concept I'm struggling with. For the I/O routines, I am envisioning applying simple inheritance: Abstract I/O class defines read & write functions to fill in the "myModel" object HDF4 derived class HDF5 HDF5 using parallel IO NetCDF etc... The code should read data in any of these formats, then write out to any of these formats. In the past, I would add an AbstractIO member to myModel and create/destroy this object depending on which I/O scheme I want. In this way, I could do something like: myModelObj.ioObj->read('input.hdf') myModelObj.ioObj->write('output.hdf') I have a bit of OOP experience but very little on the Design Patterns front, so I recently acquired the Gang of Four book "Design Patterns: Elements of Reusable Object-Oriented Software". OOP designers: Which pattern(s) would you recommend I use to integrate I/O with the myModel object? I am interested in answering this for two reasons: To learn more about design patterns in general Apply what I learn to help refactor an large old crufty/legacy physics code to be more human-readable & extensible. I am leaning towards applying the Decerator pattern to myModel, so I can attach the I/O responsibilities dynamically to myModel (i.e. whether to use HDF4, HDF5, etc.). However, I don't feel very confident that this is the best pattern to apply. Reading the Gang of Four book cover-to-cover before I start coding feels like a good way to develop an unhealthy caffeine addiction. What patterns do you recommend?

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  • ASP.NET MVC CRUD PartialView Popup Issue

    - by Smiley Face
    I am creating an MVC website which makes use of Partial Views on Popups to handle all my CRUD transactions. Please note that my application can already handle these CRUD operations perfectly (LINQ-To-Entity). However, I have a problem with my popup forms. Below is the code from my _Add.cshtml: @model MyStore.Models.MyModels.ProductsModel @{ Layout = null; } @using (Ajax.BeginForm("_Add", "Products", new AjaxOptions { InsertionMode = InsertionMode.Replace, HttpMethod = "POST", OnSuccess = "addSuccess" }, new { @id = "addForm" })) { @Html.ValidationSummary(true) <div id="add-message" class="error invisible"></div> <fieldset> <legend>Products</legend> @Html.HiddenFor(m => Model.ProductCode) <div class="editor-label"> @Html.LabelFor(model => model.ProductName) </div> <div class="editor-field"> @Html.EditorFor(model => model.ProductName) @Html.ValidationMessageFor(model => model.ProductName) </div> <div class="editor-label"> @Html.LabelFor(model => model.Price) </div> <div class="editor-field"> @Html.TextBoxFor(model => model.Price) @Html.ValidationMessageFor(model => model.Price) </div> </fieldset> } Below is the code from my Controller: [HttpGet] public ActionResult _Add(string productCode) { ProductsModel model = newProductsModel(); model.ProductCode = ProductCode ; return PartialView(model); } [HttpPost] public JsonResult _Add(ProductsModel model) { if (ModelState.IsValid) { ProductsManager prod = new ProductsManager(); Products pa = new Products(); pa.ProductCode = model.ProductCode; pa.ProductName = model.ProductName; pa.Price = model.Price; prod.AddProduct(pa); return Json(HelperClass.SuccessResponse(pa), JsonRequestBehavior.AllowGet); } else { return Json(HelperClass.ErrorResponse("Please review your form"), JsonRequestBehavior.DenyGet); } } Please note that the _Add.cshtml is a partial view which is being rendered through a Popup.js which I found on the internet. It is rendered through this code: @Html.ActionLink("[Add Product]", "_Add", new { ProductCode = @ViewData["ProductCode"] }, new { @class = "editLink" }) This works okay. I mean it adds product to my database. But my problem is upon clicking the Proceed button, I get this pop-up download dialog from the page: Can somebody please help me with this? I have a hunch it's because of the HttpMethod i'm using (POST, PUT, GET, DELETE) but i'm not really sure which one is right to use or if it really is the problem in the first place. Any help would be greatly appreciated! PS. Sorry for the long post.

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  • Makefile issue with compiling a C++ program

    - by Steve
    I recently got MySQL compiled and working on Cygwin, and got a simple test example from online to verify that it worked. The test example compiled and ran successfully. However, when incorporating MySQL in a hobby project of mine it isn't compiling which I believe is due to how the Makefile is setup, I have no experience with Makefiles and after reading tutorials about them, I have a better grasp but still can't get it working correctly. When I try and compile my hobby project I recieve errors such as: Obj/Database.o:Database.cpp:(.text+0x492): undefined reference to `_mysql_insert_id' Obj/Database.o:Database.cpp:(.text+0x4c1): undefined reference to `_mysql_affected_rows' collect2: ld returned 1 exit status make[1]: *** [build] Error 1 make: *** [all] Error 2 Here is my Makefile, it worked with compiling and building the source before I attempted to put in MySQL support into the project. The LIBMYSQL paths are correct, verified by 'mysql_config'. COMPILER = g++ WARNING1 = -Wall -Werror -Wformat-security -Winline -Wshadow -Wpointer-arith WARNING2 = -Wcast-align -Wcast-qual -Wredundant-decls LIBMYSQL = -I/usr/local/include/mysql -L/usr/local/lib/mysql -lmysqlclient DEBUGGER = -g3 OPTIMISE = -O C_FLAGS = $(OPTIMISE) $(DEBUGGER) $(WARNING1) $(WARNING2) -export-dynamic $(LIBMYSQL) L_FLAGS = -lz -lm -lpthread -lcrypt $(LIBMYSQL) OBJ_DIR = Obj/ SRC_DIR = Source/ MUD_EXE = project MUD_DIR = TestP/ LOG_DIR = $(MUD_DIR)Files/Logs/ ECHOCMD = echo -e L_GREEN = \e[1;32m L_WHITE = \e[1;37m L_BLUE = \e[1;34m L_RED = \e[1;31m L_NRM = \e[0;00m DATE = `date +%d-%m-%Y` FILES = $(wildcard $(SRC_DIR)*.cpp) C_FILES = $(sort $(FILES)) O_FILES = $(patsubst $(SRC_DIR)%.cpp, $(OBJ_DIR)%.o, $(C_FILES)) all: @$(ECHOCMD) " Compiling $(L_RED)$(MUD_EXE)$(L_NRM)."; @$(MAKE) -s build build: $(O_FILES) @rm -f $(MUD_EXE) $(COMPILER) -o $(MUD_EXE) $(L_FLAGS) $(O_FILES) @echo " Finished Compiling $(MUD_EXE)."; @chmod g+w $(MUD_EXE) @chmod a+x $(MUD_EXE) @chmod g+w $(O_FILES) $(OBJ_DIR)%.o: $(SRC_DIR)%.cpp @echo " Compiling $@"; $(COMPILER) -c $(C_FLAGS) $< -o $@ .cpp.o: $(COMPILER) -c $(C_FLAGS) $< clean: @echo " Complete compile on $(MUD_EXE)."; @rm -f $(OBJ_DIR)*.o $(MUD_EXE) @$(MAKE) -s build I like the functionality of the Makefile, instead of spitting out all the arguments etc, it just spits out the "Compiling [Filename]" etc. If I add -c to the L_FLAGS then it compiles (I think) but instead spits out stuff like: g++: Obj/Database.o: linker input file unused because linking not done After a full day of trying and research on google, I'm no closer to solving my problem, so I come to you guys to see if you can explain to me why all this is happening and if possible, steps to solve. Regards, Steve

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  • Why does my entire page reload in Chrome and Firefox when using asynchronous UpdatePanel postbacks?

    - by Alex
    Being a bit perplexed about this issue by now, I hope some of you gurus can shed some light on my problem... I've developed a AJAX-enhanced website, which has been running fine in IE, Chrome and Firefox for a year or so. I use a Timer-control to check for incoming messages every 30 seconds, and this updates an UpdatePanel showing potential new messages. Now several one of my Firefox users complain about the page refreshing every 30 seconds! I my self cannot reproduce this behaviour, but given the "30 seconds"-description, I cursed my Timer-solution as the culprit. But now, I'm experiencing this error myself, not in Firefox though, but in Google Chrome! (And only on one of my two computers!) Every 30 seconds the page reloads! But I found that it's not only related to the Timer, because all other asynchronous postbacks to the server within UpdatePanels reloads the entire page as well. This error has never been experienced in Internet Explorer (to my knowledge). As I said, this it not only related to the Timer postback, but if it's of interest to anybody the code is like this: <asp:Timer runat="server" ID="MailCheckTimer" Interval="30000" OnTick="MailChecker_Tick"></asp:Timer> <asp:UpdatePanel runat="server" ID="MailCheckerUpdatePanel" UpdateMode="Conditional"> <ContentTemplate> <div class="newmail_box" runat="server" id="newmail_box"> <!-- Content stripped for this example --> </div> </ContentTemplate> <Triggers> <asp:AsyncPostBackTrigger ControlID="MailCheckTimer" /> </Triggers> </asp:UpdatePanel> In other places of the website I call the client side __doPostBack function directly from JavaScript in relation to an UpdatePanel. Normal behaviour for this call is to updated the referenced UpdatePanel with some content, but now in Chrome this refreshes the entire page! (but again not consistently, and never in IE) Even the most fundamental UpdatePanel operations like refreshing the content after a button (inside the panel) is clicked, forces the page to reload completely: <asp:Button ID="btnSearch" runat="server" Text="Search" OnClick="btnSearch_Click"></asp:Button> And just to torment me further, I only experience this on my public website, and not in my local development environment, making it a tedious affair for me to find the actual cause! :( Any ideas on why this happens? Why so inconsistently? Has it to do with my UpdatePanel-design? Or does some security setting in Firefox/Chrome that prevent some asynchronous UpdatePanel callbacks? Any help or idea is highly appreciated!

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  • Measure width() with jQuery after DOM refresh

    - by o_O Tync
    My script dynamically creates a <ul> width left-floating <li>s inside: it's a paginator. Afterwards, the script measures width of all <li>s and summs them up. The problem is that after the nodes are injected into the document — the browser refreshed DOM and applies CSS styles which takes a while. It has a negative effect on my script: when these operations are not complete before I measure the width — my script gets a wrong value. If I perform the measure in a second — everything is ok. The thing I'm looking for is a way to detect the moment when the <ul> is fully drawn, styles applied and the width has stabilizes. Or at least a way to detect every dimensions changes. Of course I can use setTimeout(..., 100) but it's ugly and I guess — not a solution at all. If there's a way to detect width stabilization — I would do the measuring right after it to get the correct values. HTML code generated by the DOM <div> <ul> <li><a href="...">1</a></li> <li><a href="...">2</a></li> .... </ul> </div> P.S. Why I need this. My paginator's left-floating <li> items tend to move to the next line when the <ul> tries to become wider than the page itself. Even though most of <li>s are invisible because of parent <div>'s width restriction: div { width: 500px; overflow: hidden; } div ul { width: 100%; white-space: nowrap; } div ul li { display: block; float: left; } they still go down unless I specify the actual summed width of the <ul> with the script.

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  • Using pointers, references, handles to generic datatypes, as generic and flexible as possible

    - by Patrick
    In my application I have lots of different data types, e.g. Car, Bicycle, Person, ... (they're actually other data types, but this is just for the example). Since I also have quite some 'generic' code in my application, and the application was originally written in C, pointers to Car, Bicycle, Person, ... are often passed as void-pointers to these generic modules, together with an identification of the type, like this: Car myCar; ShowNiceDialog ((void *)&myCar, DATATYPE_CAR); The 'ShowNiceDialog' method now uses meta-information (functions that map DATATYPE_CAR to interfaces to get the actual data out of Car) to get information of the car, based on the given data type. That way, the generic logic only has to be written once, and not every time again for every new data type. Of course, in C++ you could make this much easier by using a common root class, like this class RootClass { public: string getName() const = 0; }; class Car : public RootClass { ... }; void ShowNiceDialog (RootClass *root); The problem is that in some cases, we don't want to store the data type in a class, but in a totally different format to save memory. In some cases we have hundreds of millions of instances that we need to manage in the application, and we don't want to make a full class for every instance. Suppose we have a data type with 2 characteristics: A quantity (double, 8 bytes) A boolean (1 byte) Although we only need 9 bytes to store this information, putting it in a class means that we need at least 16 bytes (because of the padding), and with the v-pointer we possibly even need 24 bytes. For hundreds of millions of instances, every byte counts (I have a 64-bit variant of the application and in some cases it needs 6 GB of memory). The void-pointer approach has the advantage that we can almost encode anything in a void-pointer and decide how to use it if we want information from it (use it as a real pointer, as an index, ...), but at the cost of type-safety. Templated solutions don't help since the generic logic forms quite a big part of the application, and we don't want to templatize all this. Additionally, the data model can be extended at run time, which also means that templates won't help. Are there better (and type-safer) ways to handle this than a void-pointer? Any references to frameworks, whitepapers, research material regarding this?

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  • WCF Service with callbacks coming from background thread?

    - by Mark Struzinski
    Here is my situation. I have written a WCF service which calls into one of our vendor's code bases to perform operations, such as Login, Logout, etc. A requirement of this operation is that we have a background thread to receive events as a result of that action. For example, the Login action is sent on the main thread. Then, several events are received back from the vendor service as a result of the login. There can be 1, 2, or several events received. The background thread, which runs on a timer, receives these events and fires an event in the wcf service to notify that a new event has arrived. I have implemented the WCF service in Duplex mode, and planned to use callbacks to notify the UI that events have arrived. Here is my question: How do I send new events from the background thread to the thread which is executing the service? Right now, when I call OperationContext.Current.GetCallbackChannel<IMyCallback>(), the OperationContext is null. Is there a standard pattern to get around this? I am using PerSession as my SessionMode on the ServiceContract. UPDATE: I thought I'd make my exact scenario clearer by demonstrating how I'm receiving events from the vendor code. My library receives each event, determines what the event is, and fires off an event for that particular occurrence. I have another project which is a class library specifically for connecting to the vendor service. I'll post the entire implementation of the service to give a clearer picture: [ServiceBehavior( InstanceContextMode = InstanceContextMode.PerSession )] public class VendorServer:IVendorServer { private IVendorService _vendorService; // This is the reference to my class library public VendorServer() { _vendorServer = new VendorServer(); _vendorServer.AgentManager.AgentLoggedIn += AgentManager_AgentLoggedIn; // This is the eventhandler for the event which arrives from a background thread } public void Login(string userName, string password, string stationId) { _vendorService.Login(userName, password, stationId); // This is a direct call from the main thread to the vendor service to log in } private void AgentManager_AgentLoggedIn(object sender, EventArgs e) { var agentEvent = new AgentEvent { AgentEventType = AgentEventType.Login, EventArgs = e }; } } The AgentEvent object contains the callback as one of its properties, and I was thinking I'd perform the callback like this: agentEvent.Callback = OperationContext.Current.GetCallbackChannel<ICallback>(); How would I pass the OperationContext.Current instance from the main thread into the background thread?

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  • PHP 'instanceof' failing with class constant

    - by Nathan Loding
    I'm working on a framework that I'm trying to type as strongly as I possibly can. (I'm working within PHP and taking some of the ideas that I like from C# and trying to utilize them within this framework.) I'm creating a Collection class that is a collection of domain entities/objects. It's kinda modeled after the List<T> object in .Net. I've run into an obstacle that is preventing me from typing this class. If I have a UserCollection, it should only allow User objects into it. If I have a PostCollection, it should only allow Post objects. All Collections in this framework need to have certain basic functions, such as add, remove, iterate. I created an interface, but found that I couldn't do the following: interface ICollection { public function add($obj) } class PostCollection implements ICollection { public function add(Post $obj) {} } This broke it's compliance with the interface. But I can't have the interface strongly typed because then all Collections are of the same type. So I attempted the following: interface ICollection { public function add($obj) } abstract class Collection implements ICollection { const type = 'null'; } class PostCollection { const type = 'Post'; public function add($obj) { if(!($obj instanceof self::type)) { throw new UhOhException(); } } } When I attempt to run this code, I get syntax error, unexpected T_STRING, expecting T_VARIABLE or '$' on the instanceof statement. A little research into the issue and it looks like the root of the cause is that $obj instanceof self is valid to test against the class. It appears that PHP doesn't process the entire self::type constant statement in the expression. Adding parentheses around the self::type variable threw an error regarding an unexpected '('. An obvious workaround is to not make the type variable a constant. The expression $obj instanceof $this->type works just fine (if $type is declared as a variable, of course). I'm hoping that there's a way to avoid that, as I'd like to define the value as a constant to avoid any possible change in the variable later. Any thoughts on how I can achieve this, or have I take PHP to it's limit in this regard? Is there a way of "escaping" or encapsulating self::this so that PHP won't die when processing it?

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  • Java program has errors, 80 lines of code

    - by user2961687
    I have a problem with a program. It contains a lot of errors in Eclipse. Sorry for my english and thank you in advance. Here is the task: I. Declare a class that contains private fields Jam: String taste, double weight Create constructors containing variables as parameters: (String taste, double weight), (double weight), (String taste). Parameters constructors should initialize class fields. In case the constructor does not provide the necessary parameter, it must be assumed that the field taste must have the value "No Name" and weight - 100.0. Introduce the use of all constructors creating objects that represent three kinds of jams. Note: it must be assumed that the only constructor with two parameters can be assigned to fields of the class. Declare a class Jar that contains the field Jam jam, a dedicated constructor initiating all declared fields and methods: open close isItOpen Next, create an object of class Jar and fill it with the selected type of jam, operations repeat for all the kinds of jams. This is my code this far: public class App { public static void main(String[] args) { Jam strawberry = new Jam("strawberry", 20.45); Jam raspberry = new Jam(40.50); Jam peach = new Jam("peach"); Jar jar_1 = new Jar(); Jar jar_2 = new Jar(); Jar jar_3 = new Jar(); jar_1.open(); jar_1.fillIn(strawberry); jar_2.fillIn(peach); jar_3.fillIn(raspberry); } } class Jam { String taste; double weight; public Jam(String taste, double weight) { this.taste = taste; this.weight = weight; } public Jam(double weight) { this.taste = "No name"; this.weight = weight; } public Jam(String taste) { this.taste = taste; this.weight = 100.0; } } class Jar { public Jam Jam = new Jam(); private String state_jar; public Jar() { Jam.weight = 0; Jam.taste = ""; state_jar = "closed"; } public static String open() { state_jar = open; return state_jar; } public static String close() { state_jar = "closed"; return state_jar; } public static boolean isItOpen() { return state_jar; } public void fillIn(Jam jam) { if (isItOpen == false) open(); this.Jam.weight = jam.weight; this.Jam.taste = jam.taste; this.Jam.close(); } }

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  • Continuous Form, how to add/update records with external connection

    - by Mohgeroth
    EDIT After some more research I found that I cannot use a continuous form with an unbound form since it can only reference a single record at a time. Given that I've altered my question... I have a sample form that pulls out data to enter into a table as an intermediary. Initially the form is unbound and I open connections to two main recordsets. I set the listbox's recordset equal to one of them and the forms recordset equal to the other. The problem is that I cannot add records or update existing ones. Attempting to key into the fields does nothing almost as if the field was locked (Which it is not). Settings of the recordsets are OpenKeyset and LockPessimistic. Tables are not linked, they come from an outside access database seperate from this project and must remain that way. I am using an adodb connection to get the data. Could the separation of the data from the project be causing this? Sample Code from the Form Option Compare Database Option Explicit Private conn As CRobbers_Connections Private exception As CError_Trapping Private mClient_Translations As ADODB.Recordset Private mUnmatched_Clients As ADODB.Recordset Private mExcluded_Clients As ADODB.Recordset //Construction Private Sub Form_Open(Cancel As Integer) Set conn = New CRobbers_Connections Set exception = New CError_Trapping Set mClient_Translations = New ADODB.Recordset Set mUnmatched_Clients = New ADODB.Recordset Set mExcluded_Clients = New ADODB.Recordset mClient_Translations.Open "SELECT * FROM Client_Translation" _ , conn.RBRS_Conn, adOpenKeyset, adLockPessimistic mUnmatched_Clients.Open "SELECT DISTINCT(a.Client) as Client" _ & " FROM Master_Projections a " _ & " WHERE Client NOT IN ( " _ & " SELECT DISTINCT ClientID " _ & " FROM Client_Translation);" _ , conn.RBRS_Conn, adOpenKeyset, adLockPessimistic mExcluded_Clients.Open "SELECT * FROM Clients_Excluded" _ , conn.RBRS_Conn, adOpenKeyset, adLockPessimistic End Sub //Add new record to the client translations Private Sub cmdAddNew_Click() If lstUnconfirmed <> "" Then AddRecord End If End Sub Private Function AddRecord() With mClient_Translations .AddNew .Fields("ClientID") = Me.lstUnconfirmed .Fields("ClientAbbr") = Me.txtTmpShort .Fields("ClientName") = Me.txtTmpLong .Update End With UpdateRecords End Function Private Function UpdateRecords() Me.lstUnconfirmed.Requery End Function //Load events (After construction) Private Sub Form_Load() Set lstUnconfirmed.Recordset = mUnmatched_Clients //Link recordset into listbox Set Me.Recordset = mClient_Translations End Sub //Destruction method Private Sub Form_Close() Set conn = Nothing Set exception = Nothing Set lstUnconfirmed.Recordset = Nothing Set Me.Recordset = Nothing Set mUnmatched_Clients = Nothing Set mExcluded_Clients = Nothing Set mClient_Translations = Nothing End Sub

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  • How to access a matrix in a matlab struct's field from a mex function?

    - by B. Ruschill
    I'm trying to figure out how to access a matrix that is stored in a field in a matlab structure from a mex function. That's awfully long winded... Let me explain: I have a matlab struct that was defined like the following: matrixStruct = struct('matrix', {4, 4, 4; 5, 5, 5; 6, 6 ,6}) I have a mex function in which I would like to be able to receive a pointer to the first element in the matrix (matrix[0][0], in c terms), but I've been unable to figure out how to do that. I have tried the following: /* Pointer to the first element in the matrix (supposedly)... */ double *ptr = mxGetPr(mxGetField(prhs[0], 0, "matrix"); /* Incrementing the pointer to access all values in the matrix */ for(i = 0; i < 3; i++){ printf("%f\n", *(ptr + (i * 3))); printf("%f\n", *(ptr + 1 + (i * 3))); printf("%f\n", *(ptr + 2 + (i * 3))); } What this ends up printing is the following: 4.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 I have also tried variations of the following, thinking that perhaps it was something wonky with nested function calls, but to no avail: /* Pointer to the first location of the mxArray */ mxArray *fieldValuePtr = mxGetField(prhs[0], 0, "matrix"); /* Get the double pointer to the first location in the matrix */ double *ptr = mxGetPr(fieldValuePtr); /* Same for loop code here as written above */ Does anyone have an idea as to how I can achieve what I'm trying to, or what I am potentially doing wrong? Thanks! Edit: As per yuk's comment, I tried doing similar operations on a struct that has a field called array which is a one-dimensional array of doubles. The struct containing the array is defined as follows: arrayStruct = struct('array', {4.44, 5.55, 6.66}) I tried the following on the arrayStruct from within the mex function: mptr = mxGetPr(mxGetField(prhs[0], 0, "array")); printf("%f\n", *(mptr)); printf("%f\n", *(mptr + 1)); printf("%f\n", *(mptr + 2)); ...but the output followed what was printed earlier: 4.440000 0.000000 0.000000

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  • Some clarification on rvalue references

    - by Dennis Zickefoose
    First: where are std::move and std::forward defined? I know what they do, but I can't find proof that any standard header is required to include them. In gcc44 sometimes std::move is available, and sometimes its not, so a definitive include directive would be useful. When implementing move semantics, the source is presumably left in an undefined state. Should this state necessarily be a valid state for the object? Obviously, you need to be able to call the object's destructor, and be able to assign to it by whatever means the class exposes. But should other operations be valid? I suppose what I'm asking is, if your class guarantees certain invariants, should you strive to enforce those invariants when the user has said they don't care about them anymore? Next: when you don't care about move semantics, are there any limitations that would cause a non-const reference to be preferred over an rvalue reference when dealing with function parameters? void function(T&); over void function(T&&); From a caller's perspective, being able to pass functions temporary values is occasionally useful, so it seems as though one should grant that option whenever it is feasible to do so. And rvalue references are themselves lvalues, so you can't inadvertently call a move-constructor instead of a copy-constructor, or something like that. I don't see a downside, but I'm sure there is one. Which brings me to my final question. You still can not bind temporaries to non-const references. But you can bind them to non-const rvalue references. And you can then pass along that reference as a non-const reference in another function. void function1(int& r) { r++; } void function2(int&& r) { function1(r); } int main() { function1(5); //bad function2(5); //good } Besides the fact that it doesn't do anything, is there anything wrong with that code? My gut says of course not, since changing rvalue references is kind of the whole point to their existence. And if the passed value is legitimately const, the compiler will catch it and yell at you. But by all appearances, this is a runaround of a mechanism that was presumably put in place for a reason, so I'd just like confirmation that I'm not doing anything foolish.

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  • Cepstral Analysis for pitch detection

    - by Ohmu
    Hi! I'm looking to extract pitches from a sound signal. Someone on IRC just explain to me how taking a double FFT achieves this. Specifically: take FFT take log of square of absolute value (can be done with lookup table) take another FFT take absolute value I am attempting this using vDSP I can't understand how I didn't come across this technique earlier. I did a lot of hunting and asking questions; several weeks worth. More to the point, I can't understand why I didn't think of it. I am attempting to achieve this with vDSP library. it looks as though it has functions to handle all of these tasks. However, I'm wondering about the accuracy of the final result. I have previously used a technique which scours the frequency bins of a single FFT for local maxima. when it encounters one, it uses a cunning technique (the change in phase since the last FFT) to more accurately place the actual peak within the bin. I am worried that this precision will be lost with this technique I'm presenting here. I guess the technique could be used after the second FFT to get the fundamental accurately. But it kind of looks like the information is lost in step 2. as this is a potentially tricky process, could someone with some experience just look over what I'm doing and check it for sanity? also, I've heard there is an alternative technique involving fitting a quadratic over neighbouring bins. Is this of comparable accuracy? if so, I would favour it, as it doesn't involve remembering bin phases. so questions: does this approach makes sense? Can it be improved? I'm a bit worried about And the log square component; there seems to be a vDSP function to do exactly that: vDSP_vdbcon however, there is no indication it precalculates a log-table -- I assume it doesn't, as the FFT function requires an explicit pre-calculation function to be called and passed into it. and this function doesn't. Is there some danger of harmonics being picked up? is there any cunning way of making vDSP pull out the maxima, biggest first? Can anyone point me towards some research or literature on this technique? the main question: is it accurate enough? Can the accuracy be improved? I have just been told by an expert that the accuracy IS INDEED not sufficient. Is this the end of the line? Pi PS I get SO annoyed (npi) when I want to create tags, but cannot. :| I have suggested to the maintainers that SO keep track of attempted tags, but I'm sure I was ignored. we need tags for vDSP, accelerate framework, cepstral analysis

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  • Is "Systems Designer" the job title that best describes what I do? [closed]

    - by ivo-rossi
    After having worked as Java developer for almost 3 years in the same company that I currently work at, I moved to a new position associated with the development of the same application. I’m in this new position for more than 1 year now. My official job title is Systems Designer, but I’m not sure this is a title that expresses well what I do. So my question here is what would be the most appropriate job title for me? I see this question as important for my career development. After all, I should be able to explain in one word what I do. And it’s no longer “Java Developer”. Well, in more than one word, this is what I do: The business analysts gather requirements / business problems to be solved with the clients and then discuss these requirements with me. Given the requirements, I design the high level solutions to be implemented in our system (e.g. a new screen on the client application, modifications to existing reports, extension to the XML export format of some objects, etc). I base my decision on the current capabilities of the system, the overall impact that the solutions would have on the system and the estimated effort to implement them (as I was a developer of this same application for almost 3 years before I moved to this position, I’m confident in my estimates). The solutions are discussed iteratively with the business analysts until we agree that they are good. The outcome of this analysis is what we call the “requirements design” document, which is written by me, shared with clients for approval and then also with the team that is going to implement the solutions and test them. Note that there are a few problems that I need to find a solution for that are non-functional. If the users are unhappy with the performance of a certain tool, I will investigate what can be done to speed it up. I will do some research – often based in the Java code itself - to identify possibilities of optimizations. But in this new position I no longer code, the main outcome of my work is really the “requirements design”. Is “Systems Designer” really the most appropriate job title?

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  • Slow MySQL query....only sometimes

    - by Shane N
    I have a query that's used in a reporting system of ours that sometimes runs quicker than a second, and other times takes 1 to 10 minutes to run. Here's the entry from the slow query log: # Query_time: 543 Lock_time: 0 Rows_sent: 0 Rows_examined: 124948974 use statsdb; SELECT count(distinct Visits.visitorid) as 'uniques' FROM Visits,Visitors WHERE Visits.visitorid=Visitors.visitorid and candidateid in (32) and visittime>=1275721200 and visittime<=1275807599 and (omit=0 or omit>=1275807599) AND Visitors.segmentid=9 AND Visits.visitorid NOT IN (SELECT Visits.visitorid FROM Visits,Visitors WHERE Visits.visitorid=Visitors.visitorid and candidateid in (32) and visittime<1275721200 and (omit=0 or omit>=1275807599) AND Visitors.segmentid=9); It's basically counting unique visitors, and it's doing that by counting the visitors for today and then substracting those that have been here before. If you know of a better way to do this, let me know. I just don't understand why sometimes it can be so quick, and other times takes so long - even with the same exact query under the same server load. Here's the EXPLAIN on this query. As you can see it's using the indexes I've set up: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY Visits range visittime_visitorid,visitorid visittime_visitorid 4 NULL 82500 Using where; Using index 1 PRIMARY Visitors eq_ref PRIMARY,cand_visitor_omit PRIMARY 8 statsdb.Visits.visitorid 1 Using where 2 DEPENDENT SUBQUERY Visits ref visittime_visitorid,visitorid visitorid 8 func 1 Using where 2 DEPENDENT SUBQUERY Visitors eq_ref PRIMARY,cand_visitor_omit PRIMARY 8 statsdb.Visits.visitorid 1 Using where I tried to optimize the query a few weeks ago and came up with a variation that consistently took about 2 seconds, but in practice it ended up taking more time since 90% of the time the old query returned much quicker. Two seconds per query is too long because we are calling the query up to 50 times per page load, with different time periods. Could the quick behavior be due to the query being saved in the query cache? I tried running 'RESET QUERY CACHE' and 'FLUSH TABLES' between my benchmark tests and I was still getting quick results most of the time. Note: last night while running the query I got an error: Unable to save result set. My initial research shows that may be due to a corrupt table that needs repair. Could this be the reason for the behavior I'm seeing? In case you want server info: Accessing via PHP 4.4.4 MySQL 4.1.22 All tables are InnoDB We run optimize table on all tables weekly The sum of both the tables used in the query is 500 MB MySQL config: key_buffer = 350M max_allowed_packet = 16M thread_stack = 128K sort_buffer = 14M read_buffer = 1M bulk_insert_buffer_size = 400M set-variable = max_connections=150 query_cache_limit = 1048576 query_cache_size = 50777216 query_cache_type = 1 tmp_table_size = 203554432 table_cache = 120 thread_cache_size = 4 wait_timeout = 28800 skip-external-locking innodb_file_per_table innodb_buffer_pool_size = 3512M innodb_log_file_size=100M innodb_log_buffer_size=4M

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  • Improving performance on data pasting 2000 rows with validations

    - by Lohit
    I have N rows (which could be nothing less than 1000) on an excel spreadsheet. And in this sheet our project has 150 columns like this: Now, our application needs data to be copied (using normal Ctrl+C) and pasted (using Ctrl+V) from the excel file sheet on our GUI sheet. Copy pasting 1000 records takes around 5-6 seconds which is okay for our requirement, but the problem is when we need to make sure the data entered is valid. So we have to validate data in each row generate appropriate error messages and format the data as per requirement. So we need to at runtime parse and evaluate data in each row. Now all the formatting of data and validations come from the back-end database and we have it in a data-table (dtValidateAndFormatConditions). The conditions would be around 50. So you can see how slow this whole process becomes since N X 150 X 50 operations are required to complete this whole process. Initially it took approximately 2-3 minutes but now i have reduced it to 20 - 30 seconds. However i have increased the speed by making an expression parser of my own - and not by any algorithm, is there any other way i can improve performance, by using Divide and Conquer or some other mechanism. Currently i am not really sure how to go about this. Here is what part of my code looks like: public virtual void ValidateAndFormatOnCopyPaste(DataTable DtCopied, int CurRow) { foreach (DataRow dRow in dtValidateAndFormatConditions.Rows) { string Condition = dRow["Condition"]; string FormatValue = Value = dRow["Value"]; GetValidatedFormattedData(DtCopied,ref Condition, ref FormatValue ,iRowIndex); Condition = Parse(Condition); dRow["Condition"] = Condition; FormatValue = Parse(FormatValue ); dRow["Value"] = FormatValue; } } The above code gets called row-wise like this: public override void ValidateAndFormat(DataTable dtChangedRecords, CellRange cr) { int iRowStart = cr.Row, iRowEnd = cr.Row + cr.RowCount; for (int iRow = iRowStart; iRow < iRowEnd; iRow++) { ValidateAndFormatOnCopyPaste(dtChangedRecords,iRow); } } Please know my question needs a more algorithmic solution than code optimization, however any answers containing code related optimizations will be appreciated as well. (Tagged Linq because although not seen i have been using linq in some parts of my code).

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  • How to reduce redundant code when adding new c++0x rvalue reference operator overloads

    - by Inverse
    I am adding new operator overloads to take advantage of c++0x rvalue references, and I feel like I'm producing a lot of redundant code. I have a class, tree, that holds a tree of algebraic operations on double values. Here is an example use case: tree x = 1.23; tree y = 8.19; tree z = (x + y)/67.31 - 3.15*y; ... std::cout << z; // prints "(1.23 + 8.19)/67.31 - 3.15*8.19" For each binary operation (like plus), each side can be either an lvalue tree, rvalue tree, or double. This results in 8 overloads for each binary operation: // core rvalue overloads for plus: tree operator +(const tree& a, const tree& b); tree operator +(const tree& a, tree&& b); tree operator +(tree&& a, const tree& b); tree operator +(tree&& a, tree&& b); // cast and forward cases: tree operator +(const tree& a, double b) { return a + tree(b); } tree operator +(double a, const tree& b) { return tree(a) + b; } tree operator +(tree&& a, double b) { return std::move(a) + tree(b); } tree operator +(double a, tree&& b) { return tree(a) + std::move(b); } // 8 more overloads for minus // 8 more overloads for multiply // 8 more overloads for divide // etc which also has to be repeated in a way for each binary operation (minus, multiply, divide, etc). As you can see, there are really only 4 functions I actually need to write; the other 4 can cast and forward to the core cases. Do you have any suggestions for reducing the size of this code? PS: The class is actually more complex than just a tree of doubles. Reducing copies does dramatically improve performance of my project. So, the rvalue overloads are worthwhile for me, even with the extra code. I have a suspicion that there might be a way to template away the "cast and forward" cases above, but I can't seem to think of anything.

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