Search Results

Search found 15007 results on 601 pages for 'array'.

Page 552/601 | < Previous Page | 548 549 550 551 552 553 554 555 556 557 558 559  | Next Page >

  • Error in inserting data into database

    - by Matthew
    When I try to run this code it will not insert the data into the database? <?php class Database { private $dsn; function __construct($dbname, $host, $user, $password, $enckey) { $this->dsn = "mysql:dbname=" . $dbname . ';host=' . $host; $this->user = $user; $this->password = $password; } private function createDSN() { return $this->dsn; } public function createConnection() { try { $dbh = new PDO(self::createDSN(), $this->user, $this->password); } catch (PDOException $e) { echo 'Connection failed: ' . $e->getMessage(); } return $dbh; } } $db = new Database('mytest', 'localhost', 'root', 'hashedpassword', null); $dbh = $db->createConnection(); $sql = $dbh->prepare("INSERT INTO contacts (firstname, lastname) VALUES (?,?)"); $sql->execute(array("abc", "xyz")); ?>

    Read the article

  • DynamicContent.html: Write a JavaScript in an HTML document that can change the content of an HTML e

    - by A sw A
    ShowHide.html: Write a JavaScript in an HTML document that displays an image and allows the user to toggle the image between appearing and not appearing in the document. Place your image in a (division) tag that has a style attribute. “style.visibility” can take two values: “visible” and “hidden”. The document has a button called “Toggle Image”, which calls the toggle function upon the event “onclick”. DynamicColors.html: Write a JavaScript in an HTML document that changes the background and foreground colors of the body of a document according to the user input. The document has two input texts: background color and foreground color. The colors change when the event “onchange” occurs as you type in the text input and the event handler is called. Your event handler takes two parameters: “where”, and “newColor”. To change the document color and background color you need to change the elements document.body.style.color and document.body.style.backgroundColor. Available colors are: black, silver, gray, white, maroon, red, purple, fuchsia, green, lime, olive, yellow, navy, blue, teal, and aqua. DynamicContent.html: Write a JavaScript in an HTML document that can change the content of an HTML element (a help box). The content of an element is accessed through its “value” property. The content of a help box can change depending on the placement of the mouse cursor. When the cursor is placed over a particular input field (“onmouseover” event), the help box can display advice on how the field is to be filled. When the cursor is moved away from the input field (“onmouseout” event), the help box content changes to simply indicate that assistance is available. Your messages are stored in an array of strings.

    Read the article

  • Timer C#. Start, stop, and get the amount of time between the calls

    - by user1886060
    I'm writing UDP chat with reliable data transfer. I need to start a timer when a packet is sent, and stop it as soon it receives an answer from the server(ACK- acknowledgment). Here is my code: private void sendButton_Click(object sender, EventArgs e) { Packet snd = new Packet(ack, textBox1.Text.Trim()); textBox1.Text = string.Empty; Smsg = snd.GetDataStream();//convert message into array of bytes to send. while (true) { try { // Here I need to Start a timer! clientSock.SendTo(Smsg, servEP); clientSock.ReceiveFrom(Rmsg, ref servEP); //Here I need to stop a timer and get elapsed amount of time. Packet rcv = new Packet(Rmsg); if (Rmsg != null && rcv.ACK01 != ack) continue; if (Rmsg != null && rcv.ACK01 == ack) { this.displayMessageDelegate("ack is received :"+ack); ChangeAck(ack); break; } Thank you.

    Read the article

  • C++ map performance - Linux (30 sec) vs Windows (30 mins) !!!

    - by sonofdelphi
    I need to process a list of files. The processing action should not be repeated for the same file. The code I am using for this is - using namespace std; vector<File*> gInputFileList; //Can contain duplicates, File has member sFilename map<string, File*> gProcessedFileList; //Using map to avoid linear search costs void processFile(File* pFile) { File* pProcessedFile = gProcessedFileList[pFile->sFilename]; if(pProcessedFile != NULL) return; //Already processed foo(pFile); //foo() is the action to do for each file gProcessedFileList[pFile->sFilename] = pFile; } void main() { size_t n= gInputFileList.size(); //Using array syntax (iterator syntax also gives identical performance) for(size_t i=0; i<n; i++){ processFile(gInputFileList[i]); } } The code works correctly, but... My problem is that when the input size is 1000, it takes 30 minutes - HALF AN HOUR - on Windows/Visual Studio 2008 Express (both Debug and Release builds). For the same input, it takes only 40 seconds to run on Linux/gcc! What could be the problem? The action foo() takes only a very short time to execute, when used separately. Should I be using something like vector::reserve for the map?

    Read the article

  • question about siftdown operation on heap

    - by davit-datuashvili
    i have following pseudo code which execute siftdown operation on heap array suppose is x void siftdown(int n) pre heap(2,n) && n>=0 post heap(1,n) i=1; loop /*invariant heap(1,n) except perhaps between i and it's (0,1,or 2) children*/ c=2*i; if (c>n) break; // c is left child of i if (c+1)<=n /* c+1 is rigth child of i if (x[c+1]<x[c]) c++ /* c is lesser child of i if (x[i]<=x[c]) break; swap(c,i) i=c; i have wrote following code is it correct? public class siftdown{ public static void main(String[]args){ int c; int n=9; int a[]=new int[]{19,100,17,2,7,3,36,1,25}; int i=1; while (i<n){ c=2*i; if (c>n) break; //c is the left child of i if (c+1<=n) //c+1 ir rigth child of i if (a[c+1]<a[c]) c++; if (a[i]<=a[c]) break; int t=a[c]; a[c]=a[i]; a[i]=t; i=c; } for (int j=0;j<a.length;j++){ System.out.println(a[j]); } } } // result is 19 2 17 1 7 3 36 100 25

    Read the article

  • Discussion - Allowing / blocking user access to pages / Client Side Validation (Client Side Only!) -

    - by Ozaki
    TLDR Using plain HTML / Javascript (Client Side) I want to prevent viewing of certain pages. The user will have to type a username and password and depending on that they get access to different pages. Answers can NOT include server side whatsoever It does not matter if they can break it easily. There is no sensitive information etc. Also the target audience will not have access to internet OR probably know what a cookie is... At some point the user will have to type username / password.(I can define the cookie here) Currently I thought of using cookies to set a cookie for each page to say "true" / "false" but that would get messy with so many cookies. Or setting an array within a cookie for each page? I have div field "#Content" which as it looks encompasses all of my content on the page so blocking out content will be as simple as replacing it with ("sorry you don't have access") etc. For Example: $.cookie("Access","page1, page2, page3"{ expires: 1 }); I am looking for anyway to do this does not have to be with cookies. Would be nice to get a discussion of different ways this can be done. So the question is: What do YOU think would be a good way to go about doing this with client side validation? Also on another note discussion on how to make client side more secure or ways to do so are acceptable.

    Read the article

  • php parsing csv with ftell

    - by Robert82
    I have a 500mb csv file with over 500,000 lines, each with 80 fields. I am using fget to process the file line by line. $col1 = array(); while (($row = fgetcsv($handle, 1000, ",")) !== FALSE) { $col1[] = $row[0]; } Because of an execution time limit on the PHP file by my hosting provider (120 seconds), I can't process the whole file in one run. I tried using ftell() and fseek() to remember the last position for restart. The trouble is, sometimes the ftell() position is in the middle of a row, and resuming means missing the first half of the row. Is there an elegant way to know the last line successfully processed, and resume from the one after it? I realize I can do a simple counter, and then loop through to that point again, but that would produce diminishing returns on the rows I can process towards the end of the file. Is there something like ftell() and fseek() that would work in my case? Or a way to limit ftell() to return the pointer for the end of the previous line?

    Read the article

  • How to sort NSMutableArray? Code review needed

    - by JAM
    Good evening. This code works. It sorts an array of cards by both Suit and Card Value. It is also very much brute force. Can you recommend a better way? Does Objective-C help dealing with a situation where object being sorted itself has multiple fields, on which sorting depends? -(void) sort: (NSMutableArray *) deck { NSUInteger count = [deck count]; Card *thisCard; Card *nextCard; int this; int next; BOOL stillSwapping = true; while (stillSwapping) { stillSwapping = false; for (NSUInteger i = 0; i < count; ++i) { this = i; next = i+1; if (next < count) { thisCard = [deck objectAtIndex:this]; nextCard = [deck objectAtIndex:next]; if ([thisCard suit] > [nextCard suit]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } if ([thisCard suit] == [nextCard suit]) { if ([thisCard value] > [nextCard value]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } } } } } }

    Read the article

  • RESTful API: How to model JSON representation?

    - by Jan P.
    I am designing a RESTful API for a booking application. You can request a list of accommodations. And that's where I don't really know how to design the JSON represenation. This is my XML representation: <?xml version="1.0" encoding="utf-8"?> <accommodations> <accommodation> <name>...</name> <category>couch</category> </accommodation> <accommodation> <name>...</name> <category>room</category> </accommodation> <accommodations> My first try to convert this to JSON resulted in this output (1): { "0": { "name": "...", "category": "couch" }, "1": { "name": "...", "category": "room" } } But as I looked how others APIs did it, I found something looking more like this (2): [ { "name": "...", "category": "couch" }, { "name": "...", "category": "room" } ] I know version 1 is an object, and version 2 an array. But which one is better in this case?

    Read the article

  • What is wrong with this append func in C

    - by LuckySlevin
    My Struct Definitions. typedef struct inner_list {char word[100]; inner_list*next;} inner_list; typedef struct outer_list { char word [100]; inner_list * head; outer_list * next; } outer_list; And The problem part: void append(outer_list **q,char num[100],inner_list *p) { outer_list *temp,*r; temp = *q; char *str; if(*q==NULL) { temp = (outer_list *)malloc(sizeof(outer_list)); strcpy(temp->word,num); temp->head = p; temp->next=NULL; *q=temp; } else { temp = *q; while(temp->next !=NULL) { temp=temp->next; } r = (outer_list *)malloc(sizeof(outer_list)); strcpy(r->word,num); temp->head = p; r->next=NULL; temp->next=r; } } I don't know what is i'm doing wrong in this append function i'm sending a char array and a linked list to be stored another linked list. But i can't store the linked list in another linked list. I couldn't figure out the problem. Any ideas?

    Read the article

  • How to know the type of an object in a list?

    - by nacho4d
    Hi, I want to know the type of object (or type) I have in my list so I wrote this: void **list; //list of references list = new void * [2]; Foo foo = Foo(); const char *not_table [] = {"tf", "ft", 0 }; list[0] = &foo; list[1] = not_table; if (dynamic_cast<LogicProcessor*>(list[0])) { //ERROR here ;( printf("Foo was found\n"); } if (dynamic_cast<char*> (list[0])) { //ERROR here ;( printf("char was found\n"); } but I get : error: cannot dynamic_cast '* list' (of type 'void*') to type 'class Foo*' (source is not a pointer to class) error: cannot dynamic_cast '* list' (of type 'void*') to type 'char*' (target is not pointer or reference to class) Why is this? what I am doing wrong here? Is dynamic_cast what I should use here? Thanks in advance EDIT: I know above code is much like plain C and surely sucks from the C++ point of view but is just I have the following situation and I was trying something before really implementing it: I have two arrays of length n but both arrays will never have an object at the same index. Hence, or I have array1[i]!=NULL or array2[i]!=NULL. This is obviously a waste of memory so I thought everything would be solved if I could have both kind of objects in a single array of length n. I am looking something like Cocoa's (Objective-C) NSArray where you don't care about the type of the object to be put in. Not knowing the type of the object is not a problem since you can use other method to get the class of a certain later. Is there something like it in c++ (preferably not third party C++ libraries) ? Thanks in advance ;)

    Read the article

  • InputStreamBody in HttpMime 4.0.3 settings for content-length

    - by Ram
    I am trying to send a multi part formdata post through my java code. Can someone tell me how to set Content Length in the following?? There seem to be headers involved when we use InputStreamBody which implements the ContentDescriptor interface. Doing a getContentLength on the InputStreamBody gives me -1 after i add the content. I subclassed it to give contentLength the length of my byte array but am not sure if other headers required by ContentDescriptor will be set for a proper POST. HttpClient httpclient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(myURL); ContentBody cb = new InputStreamBody(new ByteArrayInputStream(bytearray), myMimeType, filename); //ContentBody cb = new ByteArrayBody(bytearray, myMimeType, filename); MultipartEntity mpentity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE); mpentity.addPart("key", new StringBody("SOME_KEY")); mpentity.addPart("output", new StringBody("SOME_NAME")); mpentity.addPart("content", cb); httpPost.setEntity(mpentity); HttpResponse response = httpclient.execute(httpPost); HttpEntity resEntity = response.getEntity();

    Read the article

  • getting active records to display as a plist

    - by phil swenson
    I'm trying to get a list of active record results to display as a plist for being consumed by the iphone. I'm using the plist gem v 3.0. My model is called Post. And I want Post.all (or any array or Posts) to display correctly as a Plist. I have it working fine for one Post instance: [http://pastie.org/580902][1] that is correct, what I would expect. To get that behavior I had to do this: class Post < ActiveRecord::Base def to_plist attributes.to_plist end end However, when I do a Post.all, I can't get it to display what I want. Here is what happens: http://pastie.org/580909 I get marshalling. I want output more like this: [http://pastie.org/580914][2] I suppose I could just iterate the result set and append the plist strings. But seems ugly, I'm sure there is a more elegant way to do this. I am rusty on Ruby right now, so the elegant way isn't obvious to me. Seems like I should be able to override ActiveRecord and make result-sets that pull back more than one record take the ActiveRecord::Base to_plist and make another to_plist implementation. In rails, this would go in environment.rb, right?

    Read the article

  • Applying a function that may fail to all values in a list

    - by Egwor
    I want to apply a function f to a list of values, however function f might randomly fail (it is in effect making a call out to a service in the cloud). I thought I'd want to use something like map, but I want to apply the function to all elements in the list and afterwards, I want to know which ones failed and which were successful. Currently I am wrapping the response objects of the function f with an error pair which I could then effectively unzip afterwards i.e. something like g : (a->b) -> a -> [ b, errorBoolean] f : a-> b and then to run the code ... map g (xs) Is there a better way to do this? The other alternative approach was to iterate over the values in the array and then return a pair of arrays, one which listed the successful values and one which listed the failures. To me, this seems to be something that ought to be fairly common. Alternatively I could return some special value. What's the best practice in dealing with this??

    Read the article

  • Should I really use a UITableView in this situation?

    - by mystify
    Imagine you have a view like this: At the top, there is an UISegmentedControl with two segments. It functions like a tab. Pressing one segment will activate this particular content below that UISegmentedControl. Below the UISegmentedControl are some switches. These modify the way how the content should be rendered. And finally, below those switches, there's a table. Imagine a table not in sense of UITableView, but just what it really is: A table. It shows little messages like twitter messages or chat messages for example, one below the other. Like you know it from skype and other chats. Basically they're just rows with some formatting. A label, some image views, some lines, a background. Pretty basic. The data comes from an array. No core data. The whole thing including the segmented control and setup switches must be scrollable. So what I did is: I put all this stuff in an UIScrollView. Now I have to make the decision if I would use a UITableView inside there for that table part, or if I would just print a lot of rows on to the scroll view (with -drawRect:). But some problems stick in my head: Can I put a UITableView inside a UIScrollView? I assume this makes a lot of problems. I don't want that the table part is separately scrollable. Again imagine that view: First there are some basic choice things (segmented control, switches). Then there comes the table. When you scroll, the whole thing scrolls. That's mainly because this first part with the settings can be pretty big, so you would want to scroll it away. The next thing is: Can I customize UITableView in such a way, that it consists of two parts? One for that settings part, and one for the actual data to display?

    Read the article

  • How do I convert c struct from dll to C#

    - by poco
    I am converting a application from c++ to C# and have a question about the proper way to handle importing structs. I am attempting to convert a struct from a c dll into c# The struct in c looks like this typedef struct card_info { ushort r; ushort s; enum_a a; usinged long ul; ushort n; ushort* b; ushort id; } CARD_INFO; when i use [StructLayout(LayoutKind.Sequentaial)] the size of the array is 20 bytes in c#. However, if take a look at my working c++ code it is 24 bytes. I changed my c# to look like this: [StructLayout(LayoutKind.Explicit)] public struct CardInfo { [FieldOffset(0) public ushort r; [FieldOffset(2) public ushort s; [FieldOffset(4) public EnumA a; [FieldOffset(8) public ushort ul; [FieldOffset(12) public ushort n; [FieldOffset(16) public UInt32 b; [FieldOffset(20) public ushort id; } This seems to compile but I'm not convinced this is the correct way to go about doing this. Please let me know if this is correct or if there is a better way. Thanks

    Read the article

  • Store data in tableview to NSUserDefaults

    - by Jozef Vrana
    Tricks.h file #import "Tricks.h" @implementation Tricks static NSMutableArray *trickList = nil; +(NSMutableArray *)trickList { if(!trickList){ trickList = [[NSMutableArray alloc]init]; } return trickList; } @end Tricks.m file @interface Tricks : NSObject @property(strong, nonatomic) NSString *trickName; Method for adding objects to array -(IBAction)saveAction:(id)sender { Tricks *trick = [[Tricks alloc]init]; trick.trickName = self.trickLabel.text; [[Tricks trickList]insertObject:trick atIndex:0]; [self.navigationController popViewControllerAnimated:YES]; } In .h file of UITabelview class I am making a reference to tricks class, but I am sure there is error on this line. @property (strong, nonatomic) Tricks *tricks; In cellForRow method I am storing data _trick = [[NSMutableDictionary alloc]initWithObjectsAndKeys:trick,nil]; NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults]; [defaults setObject:_trick forKey:@"numberArray"]; [defaults synchronize]; NSLog(@"%@",_trick); In .m class of UITableview in viewDidLoad I want to retrieve data if([[NSUserDefaults standardUserDefaults] objectForKey:@"numberArray"] != nil) { _tricks = [[NSUserDefaults standardUserDefaults] objectForKey:@"numberArray"]; } Thanks for advices

    Read the article

  • Beginnerquestion: How to count amount of each number drawn in a Lottery and output it in a list?

    - by elementz
    I am writing this little Lottery application. Now the plan is, to count how often each number has been drawn during each iteration of the Lottery, and store this somewhere. My guess is that I would need to use a HashMap, that has 6 keys and increments the value by one everytime the respective keys number is drawn. But how would I accomplish this? My code so far: public void numberCreator() { // creating and initializing a Random generator Random rand = new Random(); // A HashMap to store the numbers picked. HashMap hashMap = new HashMap(); // A TreeMap to sort the numbers picked. TreeMap treeMap = new TreeMap(); // creating an ArrayList which will store the pool of availbale Numbers List<Integer>numPool = new ArrayList<Integer>(); for (int i=1; i<50; i++){ // add the available Numbers to the pool numPool.add(i); hashMap.put(nums[i], 0); } // array to store the lotto numbers int [] nums = new int [6]; for (int i =0; i < nums.length; i++){ int numPoolIndex = rand.nextInt(numPool.size()); nums[i] = numPool.get(numPoolIndex); // check how often a number has been called and store the new amount in the Map int counter = hashMap.get numPool.remove(numPoolIndex); } System.out.println(Arrays.toString(nums)); } Maybe someone can tell me if I have the right idea, or even how I would implement the map properly?

    Read the article

  • Need Help: adding MouseListeners to JComponents (Drawing a JComponent and then attaching a MouseListener)

    - by user1074574
    Drawing a JComponent and then attaching a MouseListener seems very simple to me, but not in this case: I'm having a problem with a MouseListener attached to a child JComponent; here's some brief code to help describe it: Note: The BGT class has implemented ActionListers/MouseListeners that do not have any code in them, and 'figures' is an array of SwingThings. public class GC extends BGT{ public GC(){ super(); buildJMenu(); drawPanel.addMouseListener(this); //drawPanel being the panel that draws the JComponents (it is a public variable in the BGT class) drawPanel.addMouseMotionListener(this); this.addMouseListener(this); } public static void main(String[] args){ GC a = new GC(); }... public void mouseClicked(MouseEvent e) { System.out.println(e.getSource()); //This only seems to print out the DrawPanel's information }... public void mouseReleased(MouseEvent e) { repaint(); ... tempMyJTextField = new MyJTextField(startX, startY, width, height); tempMyJTextField.addMouseListener(this); tempMyJTextField.addMouseMotionListener(this); figures.add(tempMyJTextField); for(int i = 0; i < figures.size(); i++) figures.get(i).addTo(drawPanel); } This is the addTo method in the MyJTextField class: public class MyJTextField extends JTextField implements SwingThing{ ... public void addTo(JPanel p) { p.add(myTextField); } ... } In the MouseClicked event it never registers that the JComponent was clicked. (The drawing/painting works fine) Thanks.

    Read the article

  • Parsing string based on initial format

    - by Kayla
    I'm trying to parse a set of lines and extract certain parts of the string based on an initial format (reading a configuration file). A little more explanation: the format can contain up to 4 parts to be formatted. This case, %S will skip the part, %a-%c will extract the part and will be treated as a string, %d as int. What I am trying to do now is to come up with some clever way to parse it. So far I came up with the following prototype. However, my pointer arithmetic still needs some work to skip/extract the parts. Ultimately each part will be stored on an array of structs. Such as: struct st_temp { char *parta; char *partb; char *partc; char *partd; }; ... #include <stdio.h> #include <string.h> #define DIM(x) (sizeof(x)/sizeof(*(x))) void process (const char *fmt, const char *line) { char c; const char *src = fmt; while ((c = *src++) != '\0') { if (c == 'S'); // skip part else if (c == 'a'); // extract %a else if (c == 'b'); // extract %b else if (c == 'c'); // extract %c else if (c == 'd'); // extract %d (int) else { printf("Unknown format\n"); exit(1); } } } static const char *input[] = { "bar 200.1 / / (zaz) - \"bon 10\"", "foo 100.1 / / (baz) - \"apt 20\"", }; int main (void) { const char *fmt = "%S %a / / (%b) - \"%c %d\""; size_t i; for(i = 0; i < DIM (input); i++) { process (fmt, input[i]); } return (0); }

    Read the article

  • num_rows is 0 when it should be >0 for php mysqli code

    - by jpporterVA
    My num_rows is coming back as 0, and I've tried calling it several ways, but I'm stuck. Here is my code: $conn = new mysqli($dbserver, "dbuser", "dbpass", $dbname); // get the data $sql = 'SELECT AT.activityName, AT.createdOn FROM userActivity UA, users U, activityType AT WHERE U.userId = UA.userId and AT.activityType = UA.activityType and U.username = ? order by AT.createdOn'; $stmt = $conn->stmt_init(); $stmt->prepare($sql); $stmt->bind_param('s', $requestedUsername); $stmt->bind_result($activityName, $createdOn); $stmt->execute(); // display the data $numrows = $stmt->num_rows; $result=array("user activity report for: " . $requestedUsername . " with " . $numrows . " rows:"); $result[]="Created On --- Activity Name"; while ($stmt->fetch()) { $msg = " " . $createdOn . " --- " . $activityName . " "; $result[] = $msg; } $stmt->close(); There are multiple rows found, and the fetch loop process them just fine. Any suggestions on what will enable me to get the number of rows returned in the query? Suggestions are much appreciated. Thanks in advance.

    Read the article

  • Value types of variable size

    - by YellPika
    I'm trying to code a small math library in C#. I wanted to create a generic vector structure where the user could define the element type (int, long, float, double, etc.) and dimensions. My first attempt was something like this... public struct Vector<T> { public readonly int Dimensions; public readonly T[] Elements; // etc... } Unfortunately, Elements, being an array, is also a reference type. Thus, doing this, Vector<int> a = ...; Vector<int> b = a; a[0] = 1; b[0] = 2; would result in both a[0] and b[0] equaling 2. My second attempt was to define an interface IVector<T>, and then use Reflection.Emit to automatically generate the appropriate type at runtime. The resulting classes would look roughly like this: public struct Int32Vector3 : IVector<T> { public int Element0; public int Element1; public int Element2; public int Dimensions { get { return 3; } } // etc... } This seemed fine until I found out that interfaces seem to act like references to the underlying object. If I passed an IVector to a function, and changes to the elements in the function would be reflected in the original vector. What I think is my problem here is that I need to be able to create classes that have a user specified number of fields. I can't use arrays, and I can't use inheritance. Does anyone have a solution? EDIT: This library is going to be used in performance critical situations, so reference types are not an option.

    Read the article

  • Why is it possible to enumerate a LinqToSql query after calling Dispose() on the DataContext?

    - by DanM
    I'm using the Repository Pattern with some LinqToSql objects. My repository objects all implement IDisposable, and the Dispose() method does only thing--calls Dispose() on the DataContext. Whenever I use a repository, I wrap it in a using person, like this: public IEnumerable<Person> SelectPersons() { using (var repository = _repositorySource.GetNew<Person>(dc => dc.Person)) { return repository.GetAll(); } } This method returns an IEnumerable<Person>, so if my understanding is correct, no querying of the database actually takes place until Enumerable<Person> is traversed (e.g., by converting it to a list or array or by using it in a foreach loop), as in this example: var persons = gateway.SelectPersons(); // Dispose() is fired here var personViewModels = ( from b in persons select new PersonViewModel { Id = b.Id, Name = b.Name, Age = b.Age, OrdersCount = b.Order.Count() }).ToList(); // executes queries In this example, Dispose() gets called immediately after setting persons, which is an IEnumerable<Person>, and that's the only time it gets called. So, a couple questions: How does this work? How can a disposed DataContext still query the database for results when I walk the IEnumerable<Person>? What does Dispose() actually do? I've heard that it is not necessary (e.g., see this question) to dispose of a DataContext, but my impression was that it's not a bad idea. Is there any reason not to dispose of it?

    Read the article

  • Creating a Variable From Two Others

    - by John
    Hello, In the HTML table below, I would like to add a third column that equals $row["countSubmissions"] times 10 plus $row["countComments"]. How could I do this? Thanks in advance, John $sqlStr = "SELECT l.loginid, l.username, COALESCE(s.total, 0) AS countSubmissions, COALESCE(c.total, 0) AS countComments FROM login l LEFT JOIN ( SELECT loginid, COUNT(1) AS total FROM submission GROUP BY loginid ) s ON l.loginid = s.loginid LEFT JOIN ( SELECT loginid, COUNT(1) AS total FROM comment GROUP BY loginid ) c ON l.loginid = c.loginid GROUP BY l.loginid ORDER BY countSubmissions DESC LIMIT 10"; $result = mysql_query($sqlStr); $arr = array(); echo "<table class=\"samplesrec1edit\">"; while ($row = mysql_fetch_array($result)) { echo '<tr>'; echo '<td class="sitename1edit1"><a href="http://www...com/.../members/index.php?profile='.$row["username"].'">'.stripslashes($row["username"]).'</a></td>'; echo '<td class="sitename1edit2">'.stripslashes($row["countSubmissions"]).'</td>'; echo '<td class="sitename1edit2">'.stripslashes($row["countComments"]).'</td>'; echo '</tr>'; } echo "</table>";

    Read the article

  • Top n items in a List ( including duplicates )

    - by Krishnan
    Trying to find an efficient way to obtain the top N items in a very large list, possibly containing duplicates. I first tried sorting & slicing, which works. But this seems unnnecessary. You shouldn't need to sort a very large list if you just want the top 20 members. So I wrote a recursive routine which builds the top-n list. This also works, but is very much slower than the non-recursive one! Question: Which is my second routine (elite2) so much slower than elite, and how do I make it faster ? My code is attached below. Thanks. import scala.collection.SeqView import scala.math.min object X { def elite(s: SeqView[Int, List[Int]], k:Int):List[Int] = { s.sorted.reverse.force.slice(0,min(k,s.size)) } def elite2(s: SeqView[Int, List[Int]], k:Int, s2:List[Int]=Nil):List[Int] = { if( k == 0 || s.size == 0) s2.reverse else { val m = s.max val parts = s.force.partition(_==m) val whole = if( parts._1.size > 1) parts._1.tail:::parts._2 else parts._2 elite2( whole.view, k-1, m::s2 ) } } def main(args:Array[String]) = { val N = 1000000/3 val x = List(N to 1 by -1).flatten.map(x=>List(x,x,x)).flatten.view println(elite2(x,20)) println(elite(x,20)) } }

    Read the article

< Previous Page | 548 549 550 551 552 553 554 555 556 557 558 559  | Next Page >