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• Unicode strings in my C# App are shown with question marks

  - by mrbamboo

  Hi, I have a header file in C++/CLR project, which contains some strings in different languages. arabic, english, german, chinese, french, japanese etc... I have a second project written in C#. Here I access the strings stored in the header file of the C++/CLR project. The encoding of the header file is Unicode - Codepage 1200 or UTF-8. the visual studio editor is able to display the strings correctly. At runtime I access these strings and assign them into a local String variable. Here I recognized that many strings are not shown correctly. Doesn't matter if I assign them or not. Accessing the original place (while debugging) shows me all the foreign strings with question marks. Especially chinese, just question marks. Example : "So?e St?ange ?ext in Ch?n?se" (This is not the best example, I know) What is the problem? I read that C# is by default UTF-16, My header file containing the strings is UTF-16 or UTF-8. I must be able to handle strings in different languages. What am I doing wrong?

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• How to implement Excel Solver functionality in C#?

  - by Vic

  Hi, I have an application in C#, I need to do some optimization calculations, like Excel Solver Add-in does, one option is certainly to write my own solver implementation, but I'm kind of short of time, so I'm looking into libraries that already exist that can help me with this. I've been trying the Microsoft Solver Foundation, which seems pretty neat and cool, the problem is that it doesn't seem to work with the kind of calculations that I need to do. At the end of this question I'm adding the information about the calculations I need to perform and optimize. So basically my question is if any of you know of any other library that I can use for this purpose, or any tutorial that can help to do my own solver, or any idea that gives me a lead to solve this issue. Thanks. Additional Info: This is the data I need to calculate: I have 7 variables, lets call them var1, var2,...,var7 The constraints for these variables are: All of them need to be 0 <= varn <= 0.5 (where n is the number of the variable) The sum of all the variables should be equal to 1 The objective is to maximize the target formula, which in Excel looks like this: (MMULT(TRANSPOSE(L26:L32),M14:M20)) / (SQRT(MMULT(MMULT(TRANSPOSE(L26:L32),M4:S10),L26:L32))) The range that you see in this formula, L26:L32, is actually the range with the variables from above, var1, var2,..., varn. M14:M20 and M4:S10 are ranges with data that I get from different sources, there are more likely decimal values. As I said before, I was using Microsoft Solver Foundation, I modeled pretty much everything with it, I created functions that handle the operations of the target formula, but when I tried to solve the model it always fail, I think it is because of the complexity of the operations. In any case, I just wanted to show these data so you can have an idea about the kind of calculations that I need to implement.

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• Find and Replace RegEx with wildcard search and addition of value

  - by fraXis

  The below code is from my other questions that I have asked here on SO. Everyone has been so helpful and I almost have a grasp with regards to RegEx but I ran into another hurdle. This is what I basically need to do in a nutshell. I need to take this line that is in a text file that I load into my content variable: X17.8Y-1.Z0.1G0H1E1 I need to do a wildcard search for the X value, Y value, Z value, and H value. When I am done, I need this written back to my text file (I know how to create the text file so that is not the problem). X17.8Y-1.G54G0T2 G43Z0.1H1M08 I have code that the kind users here have given me, except I need to create the T value at the end of the first line, and use the value from the H and increment it by 1 for the T value. For example: X17.8Y-1.Z0.1G0H5E1 would translate as: X17.8Y-1.G54G0T6 G43Z0.1H5M08 The T value is 6 because the H value is 5. I have code that does everything (does two RegEx functions and separates the line of code into two new lines and adds some new G values). But I don't know how to add the T value back into the first line and increment it by 1 of the H value. Here is my code: StreamReader reader = new StreamReader(fDialog.FileName.ToString()); string content = reader.ReadToEnd(); reader.Close(); content = Regex.Replace(content, @"X[-\d.]+Y[-\d.]+", "$0G54G0"); content = Regex.Replace(content, @"(Z(?:\d*\.)?\d+)[^H]*G0(H(?:\d*\.)?\d+)\w*", "\nG43$1$2M08"); //This must be created on a new line This code works great at taking: X17.8Y-1.Z0.1G0H5E1 and turning it into: X17.8Y-1.G54G0 G43Z0.1H5M08 but I need it turned into this: X17.8Y-1.G54G0T6 G43Z0.1H5M08 (notice the T value is added to the first line, which is the H value +1 (T = H + 1). Can someone please modify my RegEx statement so I can do this automatically? I tried to combine my two RegEx statements into one line but I failed miserably.

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• Assigning a property across threads

  - by Mike

  I have set a property across threads before and I found this post http://stackoverflow.com/questions/142003/cross-thread-operation-not-valid-control-accessed-from-a-thread-other-than-the-t about getting a property. I think my issue with the code below is setting the variable to the collection is an object therefore on the heap and therefore is just creating a pointer to the same object So my question is besides creating a deep copy, or copying the collection into a different List object is there a better way to do the following to aviod the error during the for loop. Cross-thread operation not valid: Control 'lstProcessFiles' accessed from a thread other than the thread it was created on. Code: private void btnRunProcess_Click(object sender, EventArgs e) { richTextBox1.Clear(); BackgroundWorker bg = new BackgroundWorker(); bg.DoWork += new DoWorkEventHandler(bg_DoWork); bg.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bg_RunWorkerCompleted); bg.RunWorkerAsync(lstProcessFiles.SelectedItems); } void bg_DoWork(object sender, DoWorkEventArgs e) { WorkflowEngine engine = new WorkflowEngine(); ListBox.SelectedObjectCollection selectedCollection=null; if (lstProcessFiles.InvokeRequired) { // Try #1 selectedCollection = (ListBox.SelectedObjectCollection) this.Invoke(new GetSelectedItemsDelegate(GetSelectedItems), new object[] { lstProcessFiles }); // Try #2 //lstProcessFiles.Invoke( // new MethodInvoker(delegate { // selectedCollection = lstProcessFiles.SelectedItems; })); } else { selectedCollection = lstProcessFiles.SelectedItems; } // *********Same Error on this line******************** // Cross-thread operation not valid: Control 'lstProcessFiles' accessed // from a thread other than the thread it was created on. foreach (string l in selectedCollection) { if (engine.LoadProcessDocument(String.Format(@"C:\TestDirectory\{0}", l))) { try { engine.Run(); WriteStep(String.Format("Ran {0} Succussfully", l)); } catch { WriteStep(String.Format("{0} Failed", l)); } engine.PrintProcess(); WriteStep(String.Format("Rrinted {0} to debug", l)); } } } private delegate void WriteDelegate(string p); private delegate ListBox.SelectedObjectCollection GetSelectedItemsDelegate(ListBox list); private ListBox.SelectedObjectCollection GetSelectedItems(ListBox list) { return list.SelectedItems; }

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• How to read utf-8 xml from vbs and get correct character code

  - by vkjr

  I'm trying to read xml file from vbs script. Xml is encoded in utf-8 and has appropriate header From vbs script I use microsoft xmldom parser to read xml: Dim objXMLDoc Set objXMLDoc = CreateObject( "Microsoft.XMLDOM" ) objXMLDoc.load("vbs_strings.xml") Inside xml I'm trying to write character by code using &#nnn; notation. Then I read this character from vbscript and try to get it's code using Asc() function. For some characters it works fine and read code is equal to one written. But for some characters Asc() always returns code 63. What could it be? Examples: If xml contains <section>&#195;<section> and in script I have Section variable for representing this xml node then code: Asc(Section.Text) will return value 195 and it's ok. If xml contains <section>&#110;<section> then code: Asc(Section.Text) will return value 110 and it's ok. But if xml contains <section>&#130;<section> or <section>&#156;<section> or <section>&#140;<section> Asc(Section.Text) will return value 63 and it's definitely not good. Do you know why?

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• Generic function pointers in C

  - by Lucas

  I have a function which takes a block of data and the size of the block and a function pointer as argument. Then it iterates over the data and performes a calculation on each element of the data block. The following is the essential outline of what I am doing: int myfunction(int* data, int size, int (*functionAsPointer)(int)){ //walking through the data and calculating something for (int n = 0; n < size; n++){ data[n] = (*function)(data[n]); } } The functions I am passing as arguments look something like this: int mycalculation(int input){ //doing some math with input //... return input; } This is working well, but now I need to pass an additional variable to my functionpointer. Something along the lines int mynewcalculation(int input, int someVariable){ //e.g. input = input * someVariable; //... return input; } Is there an elegant way to achieve this and at the same time keeping my overall design idea?

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• Login failed when a web service tries to communicate with SharePoint 2007

  - by tata9999

  Hi, I created a very simple webservice in ASP.NET 2.0 to query a list in SharePoint 2007 like this: namespace WebService1 { /// <summary> /// Summary description for Service1 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.ComponentModel.ToolboxItem(false)] // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. // [System.Web.Script.Services.ScriptService] public class Service1 : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World"; } [WebMethod] public string ShowSPMyList() { string username = this.User.Identity.Name; return GetList(); } private string GetList() { string resutl = ""; SPSite siteCollection = new SPSite("http://localhost:89"); using (SPWeb web = siteCollection.OpenWeb()) { SPList mylist = web.Lists["MySPList"]; SPQuery query = new SPQuery(); query.Query = "<Where><Eq><FieldRef Name=\"AssignedTo\"/><Value Type=\"Text\">Ramprasad</Value></Eq></Where>"; SPListItemCollection items = mylist.GetItems(query); foreach (SPListItem item in items) { resutl = resutl + SPEncode.HtmlEncode(item["Title"].ToString()); } } return resutl; } } } This web service runs well when tested using the built-in server of Visual Studio 2008. The username indicates exactly my domain account (domain\myusername). However when I create a virtual folder to host and launch this web service (still located in the same machine with SP2007), I got the following error when invoking ShowSPMyList() method, at the line to execute OpenWeb(). These are the details of the error: System.Data.SqlClient.SqlException: Cannot open database "WSS_Content_8887ac57951146a290ca134778ddc3f8" requested by the login. The login failed. Login failed for user 'NT AUTHORITY\NETWORK SERVICE'. Does anyone have any idea why this error happens? Why does the web service run fine inside Visual Studio 2008, but not when running stand-alone? I checked and in both cases, the username variable has the same value (domain\myusername). Thank you very much.

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• Bloated PDF created by TCPDF

  - by Yogi Yang 007

  In a web app developed in PHP we are generating Quotations and Invoices (which are very simple and of single page) using TCPDF lib. The lib is working just great but it seems to generate very large PDF files. For example in our case it is generating PDF files as large as 4 MB (+/- a few KB). How to reduce this bloating of PDF files generated by TCPDF? Here is code snippet that I am using ob_start(); include('quote_view_bag_pdf.php'); //This file is valid HTML file with PHP code to insert data from DB $quote = ob_get_contents(); //Capture the content of 'quote_view_bag_pdf.php' file and store in variable ob_end_clean(); //Code to generate PDF file for this Quote //This line is to fix a few errors in tcpdf $k_path_url=''; require_once('tcpdf/config/lang/eng.php'); require_once('tcpdf/tcpdf.php'); // create new PDF document $pdf = new TCPDF(); // remove default header/footer $pdf->setPrintHeader(false); $pdf->setPrintFooter(false); // add a page $pdf->AddPage(); // print html formated text $pdf->writeHtml($quote, true, 0, true, 0); //Insert Variables contents here. //Build Out File Name $pdf_out_file = "pdf/Quote_".$_POST['quote_id']."_.pdf"; //Close and output PDF document $pdf->Output($pdf_out_file, 'F'); $pdf->Output($pdf_out_file, 'I'); /////////////// enter code here Hope this code fragment will give some idea?

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• What is the right way to make a new XMLHttpRequest from an RJS response in Ruby on Rails?

  - by Yuri Baranov

  I'm trying to come closer to a solution for the problem of my previous question. The scheme I would like to try is following: User requests an action from RoR controller. Action makes some database queries, makes some calculations, sets some session variable(s) and returns some RJS code as the response. This code could either update a progress bar and make another ajax request. display the final result (e.g. a chart grahic) if all the processing is finished The browser evaluates the javascript representation of the RJS. It may make another (recursive? Is recursion allowed at all?) request, or just display the result for the user. So, my question this time is: how can I embed a XMLHttpRequest call into rjs code properly? Some things I'd like to know are: Should I create a new thread to avoid stack overflow. What rails helpers (if any) should I use? Have anybody ever done something similar before on Rails or with other frameworks? Is my idea sane?

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• How to analyze the efficiency of this algorithm Part 2

  - by Leonardo Lopez

  I found an error in the way I explained this question before, so here it goes again: FUNCTION SEEK(A,X) 1. FOUND = FALSE 2. K = 1 3. WHILE (NOT FOUND) AND (K < N) a. IF (A[K] = X THEN 1. FOUND = TRUE b. ELSE 1. K = K + 1 4. RETURN Analyzing this algorithm (pseudocode), I can count the number of steps it takes to finish, and analyze its efficiency in theta notation, T(n), a linear algorithm. OK. This following code depends on the inner formulas inside the loop in order to finish, the deal is that there is no variable N in the code, therefore the efficiency of this algorithm will always be the same since we're assigning the value of 1 to both A & B variables: 1. A = 1 2. B = 1 3. UNTIL (B > 100) a. B = 2A - 2 b. A = A + 3 Now I believe this algorithm performs in constant time, always. But how can I use Algebra in order to find out how many steps it takes to finish?

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• Dashcode code translation

  - by Alex Mcp

  Hi, a quick, probably easy question whose answer is probably "best practice" I'm following a tutorial for a custom-template mobile Safari webapp, and to change views around this code is used: function btnSave_ClickHandler(event) { var views = document.getElementById('stackLayout'); var front = document.getElementById('mainScreen'); if (views && views.object && front) { views.object.setCurrentView(front, true); } } My question is just about the if conditional statement. What is this triplet saying, and why do each of those things need to be verified before the view can be changed? Does views.object just test to see if the views variable responds to the object method? Why is this important? EDIT - This is/was the main point of this question, and it regards not Javascript as a language and how if loops work, but rather WHY these 3 things specifically need to be checked: Under what scenarios might views and front not exist? I don't typically write my code so redundantly. If the name of my MySQL table isn't changing, I'll just say UPDATE 'mytable' WHERE... instead of the much more verbose (and in my view, redundant) $mytable = "TheSQLTableName"; if ($mytable == an actual table && $mytable exists && entries can be updated){ UPDATE $mytable; } Whereas if the table's name (or in the JS example, the view's names) ARE NOT "hard coded" but are instead a user input or otherwise mutable, I might right my code as the DashCode example has it. So tell me, can these values "go wrong" anyhow? Thanks!

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• UnsatisfiedLinkError: The specified procedure could not be found

  - by matt

  I'm writing some JNI code in C++ to be called from an applet on Windows XP. I've been able to successfully run the applet and have the JNI library loaded and called, even going so far as having it call functions in other DLLs. I got this working by setting up the PATH system environment variable to include the directory all of my DLLs are in. So, the problem, is that I add another call that uses a new external DLL, and suddenly when loading the library, an UnsatisfiedLinkError is thrown. The message is: 'The specified procedure could not be found'. This doesn't seem to be a problem with a missing dependent DLL, because I can remove a dependent DLL and get a different message about dependent DLL missing. From what I've been able to find online, it appears that this message means that a native Java function implementation is missing from the DLL, but it's odd that it works fine without this extra bit of code. Does anyone know what might be causing this? What kinds of things can give a 'The specified procedure could not be found' messages for an UnsatisifedLinkError?

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• Setting the value of a radio button with JQuery (ASP.NET MVC)

  - by Mario

  I have 2 "lists" of (4) radio buttons {value = "0", "1", "2", "3"} in all lists. The first list needs to drive the second list (which may occur multiple times). So if an option is selected in the first list, the SAME option is selected in the second list. It sounds weird, but it has a purpose. The first list is more of a "select all" type of list, and the second list is an individual selection list(s). I have the value of the "selectall" list via JQuery: $("#selectalllist").change(function() { var str = $('input[name=selectall]:checked').val(); $(".radiolist").attr('checked', str); //This is my thinking }); The current selected value is stored in the str variable, and that is seemingly correct (I used alert to tell me what is stored, and it comes up what I expect). I just need to set the value of the next set of lists. The second line of the code I thought would set the checked value of $(".radiolist") to the stored value, but it ALWAYS set the value to the last entry (value = "3"). I'm wondering if I have the wrong attribute in the .attr('', str) call? Any thoughts?

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• Android App Build system differences between Eclipse and Ant?

  - by Amy Winarske

  The Eclipse build for my 1.6 application project is succeeding and the Ant build is failing. I'm looking for help on why they aren't behaving the same way. We are developing on Mac OSX 10.5.8 with Eclipse 3.5 against SDK 1.6 + Google APIs. There are no setting changes in Eclipse, either at workspace or project level. Similarly, our ant is also a vanilla- flavored unmodified installation of 1.7.1. JDK is 1.5.0_22. The CLASSPATH environment variable is not set. JAVA_HOME is /Library/Java/ Home The application was initially created by a team member using the Eclipse plugins. The application references two jar files, one of which has a dependency on javax.xml.bind.annotation.XmlSeeAlso, which is not defined anywhere in our code or in android.jar. The other jar file has an explicit dependency on android.jar. I generated the Ant build file using android update. The Eclipse project builds an apk and runs the application in the emulator. I think this is incorrect behavior. The Android ant project fails to build. I think this is correct behavior. MyClass.java:98: cannot access javax.xml.bind.annotation.XmlSeeAlso [javac] file javax/xml/bind/annotation/XmlSeeAlso.class not found Any ideas as to why the two build methods are behaving differently? I would expect them both to fail. Thanks! -Amy

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• Flex - Issues retrieving an XMLList

  - by BS_C3

  Hello! I'm having a problem retrieving a XMLList and I don't understand why. I have an application that is running properly. It uses some data from two xml files called division.xml and store.xml. I noticed that I have some data in division.xml that should be in store.xml, so I did a copy/paste of the data from one file to the other. This is the data I copied: <stores> <store> <odeis>101</odeis> <name></name> <password></password> <currency></currency> <currSymbol></currSymbol> </store> <store> <odeis>102</odeis> <name></name> <password></password> <currency></currency> <currSymbol></currSymbol> </store> </stores> In the application, I list all odeis codes and I need to retrieve the block store corresponding to the selected odeis code. Before moving the data into store.xml, this is how I retrieved the block: var node:XMLList = divisionData.division.(@name==HomePageData.instance.divisionName).stores.store.(odeis == HomePageData.instance.storeCodeOdeis) This is how I retrieve it after copying the data into store.xml: var node:XMLList = storeData.stores.(@name==HomePageData.instance.divisionName).store.(odeis == HomePageData.instance.storeCodeOdeis) And I'm currently getting the following error: ReferenceError: Error #1065: The variable odeis is not defined. Could anyone enlighten me? Cause I really have no clue of why it is not working... Thanks for any tips you can give. Regards, BS_C3

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• How do I retrieve row ID from an MVCContrib HTML Grid?

  - by ryandreggs

  Hi, I currently have a product view page that contains an MVCContrib HTML Grid with a select link at the beginning of each row. If the select link is clicked, it takes me to a different page. My question is whether it is possible to retrieve the productID from the row that is selected and pass that to the next page. Maybe this is posible to do with a session variable but im not sure. Any help would be greatly appreciated. Thanks in advance. Here is my view code: <% Html.Grid((List<System2__MVC2.Controllers.ProductController.ProductsSet>)ViewData["Products"]).Columns(column => { column.For(c => Html.ActionLink("Select", "Products", "Product")).DoNotEncode(); column.For(c => c.ProductID); column.For(c => c.Name); column.For(c => c.Description); column.For(c => c.Price); }).Render(); %>

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• Direct invocation vs indirect invocation in C

  - by Mohit Deshpande

  I am new to C and I was reading about how pointers "point" to the address of another variable. So I have tried indirect invocation and direct invocation and received the same results (as any C/C++ developer could have predicted). This is what I did: int cost; int *cost_ptr; int main() { cost_ptr = &cost; //assign pointer to cost cost = 100; //intialize cost with a value printf("\nDirect Access: %d", cost); cost = 0; //reset the value *cost_ptr = 100; printf("\nIndirect Access: %d", *cost_ptr); //some code here return 0; //1 } So I am wondering if indirect invocation with pointers has any advantages over direct invocation or vice-versa. Some advantages/disadvantages could include speed, amount of memory consumed performing the operation (most likely the same but I just wanted to put that out there), safeness (like dangling pointers) , good programming practice, etc. 1Funny thing, I am using the GNU C Compiler (gcc) and it still compiles without the return statement and everything is as expected. Maybe because the C++ compiler will automatically insert the return statement if you forget.

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• centos: linking lib that doesn't have a .pc file for pkg-config

  - by Paulie

  I'm trying to compile svg2pdf on centos. I think I've managed to get the required dependencies installed using yum: sudo yum install librsvg2 sudo yum install cairo The Makefile contains: MYCFLAGS=`pkg-config --cflags librsvg-2.0 cairo-pdf` -Wall -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations - Wnested-externs -fno-strict-aliasing MYLDFLAGS=`pkg-config --libs librsvg-2.0 cairo-pdf` After typing 'make', the first couple of lines of output are: cc `pkg-config --cflags librsvg-2.0 cairo-pdf` -Wall -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wnested-externs -fno-strict-aliasing `pkg-config --libs librsvg-2.0 cairo-pdf` svg2pdf.c -o svg2pdf Package librsvg-2.0 was not found in the pkg-config search path. Perhaps you should add the directory containing `librsvg-2.0.pc' to the PKG_CONFIG_PATH environment variable No package 'librsvg-2.0' found There is no librsvg-2.0.pc on this system (but there is when I installed this using macports on my macbookpro). How should I get this package linked? Should I change the Makefile, and if so, to what? Should I generate the .pc files, and if so, how? Or is there another way to resolve this? Or, has anyone been successful at installing svg2pdf on centos, and, if so, how did you manage it? I don't have much experience on linux, so I might be missing something obvious.

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• php get, random records, and the back button

  - by Andrew Heath

  My site has a library full of games, nations, game scenarios, etc. library.php is given a type=___ & id=___ for example library.php?type=scenario&id=ABCD001 library.php saves the id to a session variable and loads an include appropriate for the type This all works just dandy. Now, I wanted to give my users the option of pulling up a random scenario. To do that, I added a special id to the logic within lib-scenario.php (the include) such that if given library.php?type=scenario&id=random the include knows to run an alternate query for a random record rather than for the actual id This also works just dandy... unless someone hits the Random Scenario button two+ times in a row, and decides that the previous random scenario was way cooler, I want to go back to that. Because the http address is always directory/library.php?type=scenario&id=random no matter how many times you click Random Scenario, as soon as you click back you'll be taken to the last page with an alternate address you visited. So, if you start at the Home page, and hit Random Scenario 35 times, then decide the 34th one was what you wanted and click BACK, you'll be put back onto the Home page. I must admit this was not a problem I had anticipated. One of my testers was the first to have the urge to back-up in the random scenario stream and here we are. How can I add back-up functionality to my script?

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• problem in json response from server to client using jquery

  - by user1400

  hello i try to use ajax and zend framework in my application , i could pass variable to server but i can not get data from server , it does not return values, it return all html code page, where is my mistake? or should i config other thing? $('#myForm').submit(function($e){ $e.preventDefault(); var $paramToServer=$("#myForm").serialize(); $.ajax({ type:'POST', url:'test', data:$paramToServer , success:function(re){ var res = $.evalJSON(re); console.log(res.id); // to see in firebog }, dataType:'json' }); }); public function testAction() { $this->_helper->getHelper('viewRenderer')->setNoRender(); //disable layout Zend_Layout::getMvcInstance()->disableLayout(); $name=$this->getRequest()->getParam ( 'name' ); //pass $name to server $return = array( 'id' => '5', 'family' => 'hello ', ); $return = Zend_Json::encode( $return); // Response $this->getResponse()->setBody($return); } thanks

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• Why do properties behave this way?

  - by acidzombie24

  from http://csharpindepth.com/Articles/Chapter8/PropertiesMatter.aspx using System; struct MutableStruct { public int Value { get; set; } public void SetValue(int newValue) { Value = newValue; } } class MutableStructHolder { public MutableStruct Field; public MutableStruct Property { get; set; } } class Test { static void Main(string[] args) { MutableStructHolder holder = new MutableStructHolder(); // Affects the value of holder.Field holder.Field.SetValue(10); // Retrieves holder.Property as a copy and changes the copy holder.Property.SetValue(10); Console.WriteLine(holder.Field.Value); Console.WriteLine(holder.Property.Value); } } 1) Why is a copy (of Property?) being made? 2) When changing the code to holder.Field.value and holder.Property.value = 10 i get the error below. That just blew my mind Error 1 Cannot modify the return value of 'MutableStructHolder.Property' because it is not a variable Why would i ever not be allowed to assign a value inside of a property!?! both property are get/set! and finally WHY would you EVER want behavior mentioned in 1 and 2. (It never came up for me, i always used get only properties). Please explain well, i cant imagine ever wanting the 2nd much less then the first. It is just so weird to me.

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• Passing control references as ref parameters

  - by Enmanuel

  Hi everyone. Please help me out here because im getting kind of confused.. I have a form in a C# winforms project and a couple of methods that are suposed to perform some tasks for this particular form and all derived ones, so one of those helper methods can make the example.. this one should fill comboboxes with a dataset. Its working properly now but when i coded the method with this signature protected void FillComboBox(kComboBox target, IEntClass_DA entity) { target.DataSource = entity.GetList().Tables[0]; target.DisplayMember = "name"; target.ValueMember = "id"; } I saw that the displayMember and ValueMember in the comboboxes were not holding the values after the method call. I just thought I should use ref parameters so the asignments are not wasted in read-only reference variables. It was ok by then but later, making an exercise of passing the whole form as a parameter I was warned by the compiler with the notice that this could not be passed as a ref parameter because it is read-only. Fine then, I keep working and see that even without the ref keyword i can use the ref variable from the form, update some properties and see the changes. So whats happening here: passing a reference of the control to the helper method gives me ability to change its members even when not using the ref parameter?? Thanks.

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• Using MD5 to generate an encryption key from password?

  - by Charles

  I'm writing a simple program for file encryption. Mostly as an academic exercise but possibly for future serious use. All of the heavy lifting is done with third-party libraries, but putting the pieces together in a secure manner is still quite a challenge for the non-cryptographer. Basically, I've got just about everything working the way I think it should. I'm using 128-bit AES for the encryption with a 128-bit key length. I want users to be able to enter in variable-length passwords, so I decided to hash the password with MD5 and then use the hash as the key. I figured this was acceptable--the key is always supposed to be a secret, so there's no reason to worry about collision attacks. Now that I've implemented this, I ran across a couple articles indicating that this is a bad idea. My question is: why? If a good password is chosen, the cipher is supposed to be strong enough on its own to never reveal the key except via an extraordinary (read: currently infeasible) brute-force effort, right? Should I be using something like PBKDF2 to generate the key or is that just overkill for all but the most extreme cryptographic applications?

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• using alias parameters in window command prompt

  - by freshWoWer

  Source:http://jpsoft.com/help/index.htm?alias.htm Aliases can use command line parameters or parameters like those in batch files. The command line parameters are numbered from %0 to %511. (%0 contains the alias name.) For example, the following alias will change directories, perform a command, and return to the original directory: alias in pushd %1 & %2$ & popd when i run the above, my command prompt gives error saying %1 * Unable to read value of alias * '%2' is not recognized as an internal or external command, operable program or batch file. 'popd`' is not recognized as an internal or external command, operable program or batch file. if you use double quote instead, alias in "pushd %1 & dir & popd" it doesn't interprets the %1 when you execute the alias C:\abc\defalias Dumping all defined aliases for CMD.EXE. in =pushd %1 & dir & popd alias def wont work ---------EDIT------------ let me try some sample output with a simple echo alias D:\abc\defalias /? Usage: ALIAS [-v] [-p programName] [-f filespec] [ ] [-v] means verbose output. [-d] means delete aliases. [-p programName] specifies which image file name these alias definitions are for. Default is CMD.EXE [-f filespec] specifies a file which contains the alises. C:\Office\dev15alias out 'echo %1' %1' * Unable to read value of alias * C:\Office\dev15alias out backtick echo %1 backtick %1` * Unable to read value of alias * C:\Office\dev15alias out "echo %1" C:\Office\dev15alias Dumping all defined aliases for CMD.EXE. out =echo %1 C:\Office\dev15out abc %1 C:\Office\dev15alias out echo %1 %1 * Unable to read value of alias * C:\Office\dev15out abc ECHO is on. Problem is, both single quote and back tick produces error, while double quote wont treat %1 as variable parameter

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• 'strcpy' error and warning

  - by Leejo

  I'm getting a 'strcpy' error and warning for the following lines: _tcscpy(strCommandLine,_T("MyProgram.exe /param1")); _tcscpy(strApplicationName,_T("MyProgram.exe")); Not sure why I'm getting a 'strcpy' error or warning since I'm not using 'strcpy'. The only lines related to this is: LPCTSTR strApplicationName; LPTSTR strCommandLine; _tcscpy(strCommandLine,_T("MyProgram.exe /param1")); //warning is on this line _tcscpy(strApplicationName,_T("MyProgram.exe")); //error is on this line The output is: 1c:\documents and settings\X.X\my documents\sandbox\sample.cpp(52) : warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details. 1 c:\program files\microsoft visual studio 8\vc\include\string.h(74) : see declaration of 'strcpy' 1c:\documents and settings\X.X\my documents\sandbox\sample.cpp(53) : error C2664: 'strcpy' : cannot convert parameter 1 from 'LPCTSTR' to 'char *' 1 Conversion loses qualifiers Any ideas on what this could means? These are my headers: iostream windows.h stdio.h tchar.h winnt.h

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