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  • Crash in OS X Core Data Utility Tutorial

    - by vinogradov
    I'm trying to follow Apple's Core Data utility Tutorial. It was all going nicely, until... The tutorial uses a custom sub-class of NSManagedObject, called 'Run'. Run.h looks like this: #import <Foundation/Foundation.h> #import <CoreData/CoreData.h> @interface Run : NSManagedObject { NSInteger processID; } @property (retain) NSDate *date; @property (retain) NSDate *primitiveDate; @property NSInteger processID; @end Now, in Run.m we have an accessor method for the processID variable: - (void)setProcessID:(int)newProcessID { [self willChangeValueForKey:@"processID"]; processID = newProcessID; [self didChangeValueForKey:@"processID"]; } In main.m, we use functions to set up a managed object model and context, instantiate an entity called run, and add it to the context. We then get the current NSprocessInfo, in preparation for setting the processID of the run object. NSManagedObjectContext *moc = managedObjectContext(); NSEntityDescription *runEntity = [[mom entitiesByName] objectForKey:@"Run"]; Run *run = [[Run alloc] initWithEntity:runEntity insertIntoManagedObjectContext:moc]; NSProcessInfo *processInfo = [NSProcessInfo processInfo]; Next, we try to call the accessor method defined in Run.m to set the value of processID: [run setProcessID:[processInfo processIdentifier]]; And that's where it's crashing. The object run seems to exist (I can see it in the debugger), so I don't think I'm messaging nil; on the other hand, it doesn't look like the setProcessID: message is actually being received. I'm obviously still learning this stuff (that's what tutorials are for, right?), and I'm probably doing something really stupid. However, any help or suggestions would be gratefully received! ===MORE INFORMATION=== Following up on Jeremy's suggestions: The processID attribute in the model is set up like this: NSAttributeDescription *idAttribute = [[NSAttributeDescription alloc]init]; [idAttribute setName:@"processID"]; [idAttribute setAttributeType:NSInteger32AttributeType]; [idAttribute setOptional:NO]; [idAttribute setDefaultValue:[NSNumber numberWithInteger:-1]]; which seems a little odd; we are defining it as a scalar type, and then giving it an NSNumber object as its default value. In the associated class, Run, processID is defined as an NSInteger. Still, this should be OK - it's all copied directly from the tutorial. It seems to me that the problem is probably in there somewhere. By the way, the getter method for processID is defined like this: - (int)processID { [self willAccessValueForKey:@"processID"]; NSInteger pid = processID; [self didAccessValueForKey:@"processID"]; return pid; } and this method works fine; it accesses and unpacks the default int value of processID (-1). Thanks for the help so far!

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  • c#: Design advice. Using DataTable or List<MyObject> for a generic rule checker

    - by Andrew White
    Hi, I have about 100,000 lines of generic data. Columns/Properties of this data are user definable and are of the usual data types (string, int, double, date). There will be about 50 columns/properties. I have 2 needs: To be able to calculate new columns/properties using an expression e.g. Column3 = Column1 * Column2. Ultimately I would like to be able to use external data using a callback, e.g. Column3 = Column1 * GetTemperature The expression is relatively simple, maths operations, sum, count & IF are the only necessary functions. To be able to filter/group the data and perform aggregations e.g. Sum(Data.Column1) Where(Data.Column2 == "blah") As far as I can see I have two options: 1. Using a DataTable. = Point 1 above is achieved by using DataColumn.Expression = Point 2 above is acheived by using DataTable.DefaultView.RowFilter & C# code 2. Using a List of generic Objects each with a Dictionary< string, object to store the values. = Point 1 could be achieved by something like NCalc = Point 2 is achieved using LINQ DataTable: Pros: DataColumn.Expression is inbuilt Cons: RowFilter & coding c# is not as "nice" as LINQ, DataColumn.Expression does not support callbacks(?) = workaround could be to get & replace external value when creating the calculated column GenericList: Pros: LINQ syntax, NCalc supports callbacks Cons: Implementing NCalc/generic calc engine Based on the above I would think a GenericList approach would win, but something I have not factored in is the performance which for some reason I think would be better with a datatable. Does anyone have a gut feeling / experience with LINQ vs. DataTable performance? How about NCalc? As I said there are about 100,000 rows of data, with 50 columns, of which maybe 20 are calculated. In total about 50 rules will be run against the data, so in total there will be 5 million row/object scans. Would really appreciate any insights. Thx. ps. Of course using a database + SQL & Views etc. would be the easiest solution, but for various reasons can't be implemented.

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  • php pdo connection scope

    - by Scarface
    Hey guys I have a connection class I found for pdo. I am calling the connection method on the page that the file is included on. The problem is that within functions the $conn variable is not defined even though I stated the method was public (bare with me I am very new to OOP), and I was wondering if anyone had an elegant solution other then using global in every function. Any suggestions are greatly appreciated. CONNECTION class PDOConnectionFactory{ // receives the connection public $con = null; // swich database? public $dbType = "mysql"; // connection parameters // when it will not be necessary leaves blank only with the double quotations marks "" public $host = "localhost"; public $user = "user"; public $senha = "password"; public $db = "database"; // arrow the persistence of the connection public $persistent = false; // new PDOConnectionFactory( true ) <--- persistent connection // new PDOConnectionFactory() <--- no persistent connection public function PDOConnectionFactory( $persistent=false ){ // it verifies the persistence of the connection if( $persistent != false){ $this->persistent = true; } } public function getConnection(){ try{ // it carries through the connection $this->con = new PDO($this->dbType.":host=".$this->host.";dbname=".$this->db, $this->user, $this->senha, array( PDO::ATTR_PERSISTENT => $this->persistent ) ); // carried through successfully, it returns connected return $this->con; // in case that an error occurs, it returns the error; }catch ( PDOException $ex ){ echo "We are currently experiencing technical difficulties. We have a bunch of monkies working really hard to fix the problem. Check back soon: ".$ex->getMessage(); } } // close connection public function Close(){ if( $this->con != null ) $this->con = null; } } PAGE USED ON include("includes/connection.php"); $db = new PDOConnectionFactory(); $conn = $db->getConnection(); function test(){ try{ $sql = 'SELECT * FROM topic'; $stmt = $conn->prepare($sql); $result=$stmt->execute(); } catch(PDOException $e){ echo $e->getMessage(); } } test();

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  • Difficulty adding widgets to django form.

    - by codingJoe
    I have a django app that tracks activities that can benefit a classroom. Using the django examples, I was able to build a form to enter this data. But when I try to add widgets to that form, things get tricky. What I want is a calendar widget that lets the user enter the 'activity_date' field using a widget. If I use Admin interface. The AdminDateWidget works fine. however. This particular user isn't allowed access to the admin interface so I need a different way to present this widget. Also I couldn't figure out how to make the bring the admin widget over into non-admin pages. So I tried a custom widget. This is the first custom widget I've built, so I'm not quite sure what is supposed to be going on here. Any Expert Advice? How do I get my date widget to work? # The Model class Activity(models.Model): activity_date = models.DateField() activity_type = models.CharField(max_length=50, choices=ACTIVITY_TYPES) activity_description = models.CharField(max_length=200) activity_duration= models.DecimalField(decimal_places=2, max_digits=4) est_attendance = models.IntegerField("Estimated attendance") # The Form class ActivityForm(forms.ModelForm): # The following line causes lockup if enabled. # With the DateTimeWidget removed, the form functions correctly except that there is no widget. #activity_date = forms.DateField(label=_('Date'), widget=DateTimeWidget) ##!!! Point of Error !!! class Meta: model = Activity fields = ('activity_date', 'activity_type', 'activity_description', 'activity_duration', 'est_attendance') def __init__(self, *args, **kwargs): super(ActivityForm, self).__init__(*args, **kwargs) instance = getattr(self, 'instance', None) edit_aid = kwargs.get('edit_aid', False) # On a different approach, the following also didn't work. #self.fields['activity_date'].widget = widgets.AdminDateWidget() # The Widget # Example referenced: http://djangosnippets.org/snippets/391/ calbtn = u""" <button id="calendar-trigger">...</button> <img src="%s/site_media/images/icon_calendar.gif" alt="calendar" id="%s_btn" style="cursor: pointer; border: 1px solid #8888aa;" title="Select date and time" onmouseover="this.style.background='#444444';" onmouseout="this.style.background=''" /> <script type="text/javascript"> Calendar.setup({ trigger : "calendar-trigger", inputField : "%s" }); </script>""" class DateTimeWidget(forms.widgets.TextInput): dformat = '%Y-%m-%d %H:%M' def render(self, name, value, attrs=None): print "DTWgt render name=%s, value=%s" % name, value if value is None: value = '' final_attrs = self.build_attrs(attrs, type=self.input_type, name=name) if value != '': try: final_attrs['value'] = \ force_unicode(value.strftime(self.dformat)) except: final_attrs['value'] = \ force_unicode(value) if not final_attrs.has_key('id'): final_attrs['id'] = u'%s_id' % (name) id = final_attrs['id'] jsdformat = self.dformat #.replace('%', '%%') cal = calbtn % (settings.MEDIA_URL, id, id, jsdformat, id) a = u'<input%s />%s' % (forms.util.flatatt(final_attrs), cal) print "render return %s " % a return mark_safe(a) def value_from_datadict(self, data, files, name): print "DTWgt value_from_datadict" dtf = forms.fields.DEFAULT_DATETIME_INPUT_FORMATS empty_values = forms.fields.EMPTY_VALUES value = data.get(name, None) if value in empty_values: return None if isinstance(value, datetime.datetime): return value if isinstance(value, datetime.date): return datetime.datetime(value.year, value.month, value.day) for format in dtf: try: return datetime.datetime(*time.strptime(value, format)[:6]) except ValueError: continue return None

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  • MATLAB: different function returns from command line and within function

    - by Myx
    Hello: I have an extremely bizzare situation: I have a function in MATLAB which calls three other main functions and produces two figures for me. The function reads in an input jpeg image, crops it, segments it using kmeans clustering, and outputs 2 figures to the screen - the original image and the clustered image with the cluster centers indicated. Here is the function in MATLAB: function [textured_avg_x photo_avg_x] = process_database_images() clear all warning off %#ok type_num_max = 3; % type is 1='texture', 2='graph', or 3='photo' type_num_max = 1; img_max_num_photo = 100; % 400 photo images img_max_num_other = 100; % 100 textured, and graph images for type_num = 1:2:type_num_max if(type_num == 3) img_num_max = img_max_num_photo; else img_num_max = img_max_num_other; end img_num_max = 1; for img_num = 1:img_num_max [type img] = load_image(type_num, img_num); %img = imread('..\images\445.jpg'); img = crop_image(img); [IDX k block_bounds features] = segment_image(img); end end end The function segment_image first shows me the color image that was passed in, performs kmeans clustering, and outputs the clustered image. When I run this function on a particular image, I get 3 clusters (which is not what I expect to get). When I run the following commands from the MATLAB command prompt: >> img = imread('..\images\texture\1.jpg'); >> img = crop_image(img); >> segment_image(img); then the first image that is displayed by segment_image is the same as when I run the function (so I know that the clustering is done on the same image) but the number of clusters is 16 (which is what I expect). In fact, when I run my process_database_images() function on my entire image database, EVERY image is evaluated to have 3 clusters (this is a problem), whereas when I test some images individually, I get in the range of 12-16 clusters, which is what I prefer and expect. Why is there such a discrepancy? Am I having some syntax bug in my process_database_images() function? If more code is required from me (i.e. segment_images function, or crop_image function), please let me know. Thanks.

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  • AJAX response not valid in C++ but Apache

    - by fehergeri
    I want to make a server written in C++ to power my game. I learned the basics of sockets and wrote a basic chat program that worked well. Now I want to create an HTTP server like Apache, but only for the AJAX request-response part. I think just for the beginning i copied one Apache response text, and i sent the exact response with the C++ server program. The problem that is that the browser (Firefox) connnects to the apache and everything works fine, except all of the requests get a correct response. But if i send this with the C++ client, then FireBug tells me that the response status is OK (200) but there is no actual response text. (How is this possible?) This response-text is exactly the same what apache sends. I made a bit-bit comparison and they were the same. The php file wich is the original response <?php echo "AS";echo rand(0,9); ?> And the origional source code: Socket.h http://pastebin.com/bW9qxtrR Socket.cpp http://pastebin.com/S3c8RFM7 main.cpp http://pastebin.com/ckExuXsR index.html http://pastebin.com/mcfEEqPP < this is the requester file. ajax.js http://pastebin.com/uXJe9hVC benchmark.js http://pastebin.com/djSYtKg9 jQuery is not needed. The main.cpp there is lot of trash code like main3 and main4 functions, these do not affect the result. I know that the response stuff in the C++ code is not really good because the connection closing is not the best; I will fix that later now I want to send a success response first. UPDATE: now i tested today a lot again and i find out there is no problem with the socket. I used the fiddler program to capture the the good answer and to capture the bad. They were the same. After this i turned off my socket application, and forced fiddler to auto respond, and the answer from the 'bad' answer still bat. So after that i replaced the bad with the good and nothing happedned. The bad answer with the good text still bad on the :8888 port but the other on the original :80 port was good, but they were absolutly the same and the same program sended it (fiddler) i think there is something missing if the response is not on the same server address (even not the same port). UPDATE: oh my god! i cant send ajax request to a remote server. now i know this.

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  • Seeking STL-aware c++filt

    - by Don Wakefield
    In my development environment, I'm compiling a code base using GNU C++ 3.4.6. Code is under development, and unfortunately crashes now and then. It's nice to be able to run the traceback through a demangler, and I use c++filt 3.4. The problem comes when functions have a number of STL parameters. Consider My_callback::operator()( Status&, std::set<std::string> const&, std::vector<My_parameter*> const&, My_attribute_set const&, std::vector<My_parameter_base*> const&, std::vector<My_parameter> const&, std::set<std::string> const& ) { // ... } When this function is in the traceback, the mangled output on my platform is: (_ZN30My_callbackclER11StatusRKSt3setISsSt4lessISsESaISsEERKSt6vectorIP13My_parameterSaISB_EERK17My_attribute_setRKS9_IP18My_parameter_baseSaISK_EERKS9_ISA_SaISA_EES8_+0x76a) [0x13ffdaa] c++filt kindly demangles it to (My_callback::operator()(Status&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, std::vector<My_parameter*, std::allocator<My_parameter*> > const&, My_attribute_set const&, std::vector<My_parameter_base*, std::allocator<My_parameter_base*> > const&, std::vector<My_parameter, std::allocator<My_parameter> > const&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&)+0x76a) [0x13ffdaa] This is the same problem as compiler errors encountered when using templates. However, the STL is a fairly regular and recognizable package of templates. So what I'm hoping is that someone out there has created an enhanced version of c++filt which would dump something closer to the original function signature. Any hints?

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  • What benefits are there to storing Javascript in external files vs in the <head>?

    - by RenderIn
    I have an Ajax-enabled CRUD application. If I display a record from my database it shows that record's values for each column, including its primary key. For the Ajax actions tied to buttons on the page I am able to set up their calls by printing the ID directly into their onclick functions when rendering the HTML server-side. For example, to save changes to the record I may have a button as follows, with '123' being the primary key of the record. <button type="button" onclick="saveRecord('123')">Save</button> Sometimes I have pages with Javascript generating HTML and Javascript. In some of these cases the primary key is not naturally available at that place in the code. In these cases I took a shortcut and generate buttons like so, taking the primary key from a place it happens to be displayed on screen for visual consumption: ... <td>Primary Key: </td> <td><span id="PRIM_KEY">123</span></td> ... <button type="button" onclick="saveRecord(jQuery('#PRIM_KEY').text())">DoSomething</button> This definitely works, but it seems wrong to drive database queries based on the value of text whose purpose was user consumption rather than method consumption. I could solve this by adding a series of additional parameters to various methods to usher the primary key along until it is eventually needed, but that also seems clunky. The most natural way for me to solve this problem would be to simply situate all the Javascript which currently lives in external files, in the <head> of the page. In that way I could generate custom Javascript methods without having to pass around as many parameters. Other than readability, I'm struggling to see what benefit there is to storing Javascript externally. It seems like it makes the already weak marriage between HTML/DOM and Javascript all the more distant. I've seen some people suggest that I leave the Javascript external, but do set various "custom" variables on the page itself, for example, in PHP: <script type="text/javascript"> var primaryKey = <?php print $primaryKey; ?>; </script> <script type="text/javascript" src="my-external-js-file-depending-on-primaryKey-being-set.js"></script> How is this any better than just putting all the Javascript on the page in the first place? There HTML and Javascript are still strongly dependent on each other.

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  • Different function returns from command line and within function

    - by Myx
    Hello: I have an extremely bizzare situation: I have a function in MATLAB which calls three other main functions and produces two figures for me. The function reads in an input jpeg image, crops it, segments it using kmeans clustering, and outputs 2 figures to the screen - the original image and the clustered image with the cluster centers indicated. Here is the function in MATLAB: function [textured_avg_x photo_avg_x] = process_database_images() clear all warning off %#ok type_num_max = 3; % type is 1='texture', 2='graph', or 3='photo' type_num_max = 1; img_max_num_photo = 100; % 400 photo images img_max_num_other = 100; % 100 textured, and graph images for type_num = 1:2:type_num_max if(type_num == 3) img_num_max = img_max_num_photo; else img_num_max = img_max_num_other; end img_num_max = 1; for img_num = 1:img_num_max [type img] = load_image(type_num, img_num); %img = imread('..\images\445.jpg'); img = crop_image(img); [IDX k block_bounds features] = segment_image(img); end end end The function segment_image first shows me the color image that was passed in, performs kmeans clustering, and outputs the clustered image. When I run this function on a particular image, I get 3 clusters (which is not what I expect to get). When I run the following commands from the MATLAB command prompt: >> img = imread('..\images\texture\1.jpg'); >> img = crop_image(img); >> segment_image(img); then the first image that is displayed by segment_image is the same as when I run the function (so I know that the clustering is done on the same image) but the number of clusters is 16 (which is what I expect). In fact, when I run my process_database_images() function on my entire image database, EVERY image is evaluated to have 3 clusters (this is a problem), whereas when I test some images individually, I get in the range of 12-16 clusters, which is what I prefer and expect. Why is there such a discrepancy? Am I having some syntax bug in my process_database_images() function? If more code is required from me (i.e. segment_images function, or crop_image function), please let me know. Thanks.

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  • Establishing a tcp connection from within a DLL

    - by Nicholas Hollander
    I'm trying to write a piece of code that will allow me to establish a TCP connection from within a DLL file. Here's my situation: I have a ruby application that needs to be able to send and receive data over a socket, but I can not access the native ruby socket methods because of the environment in which it will be running. I can however access a DLL file and run the functions within that, so I figured I would create a wrapper for winsock. Unfortunately, attempting to take a piece of code that should connect to a TCP socket in a normal C++ application throws a slew of LNK2019 errors that I can not for the life of me resolve. This is the method I'm using to connect: //Socket variable SOCKET s; //Establishes a connection to the server int server_connect(char* addr, int port) { //Start up Winsock WSADATA wsadata; int error = WSAStartup(0x0202, &wsadata); //Check if something happened if (error) return -1; //Verify Winock version if (wsadata.wVersion != 0x0202) { //Clean up and close WSACleanup(); return -2; } //Get the information needed to finalize a socket SOCKADDR_IN target; target.sin_family = AF_INET; //Address family internet target.sin_port = _WINSOCKAPI_::htons(port); //Port # target.sin_addr.s_addr = inet_addr(addr); //Create the socket s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if (s == INVALID_SOCKET) { return -3; } //Try connecting if (connect(s, (SOCKADDR *)&target, sizeof(target)) == SOCKET_ERROR) { //Failed to connect return -4; } else { //Success return 1; } } The exact errors that I'm receiving are: Error 1 error LNK2019: unresolved external symbol _closesocket@4 referenced in function _server_disconnect [Project Path] Error 2 error LNK2019: unresolved external symbol _connect@12 referenced in function _server_connect [Project Path] Error 3 error LNK2019: unresolved external symbol _htons@4 referenced in function _server_connect [Project Path] Error 4 error LNK2019: unresolved external symbol _inet_addr@4 referenced in function _server_connect [Project Path] Error 5 error LNK2019: unresolved external symbol _socket@12 referenced in function _server_connect [Project Path] Error 6 error LNK2019: unresolved external symbol _WSAStartup@8 referenced in function _server_connect [Project Path] Error 7 error LNK2019: unresolved external symbol _WSACleanup@0 referenced in function _server_connect [Project Path] Error 8 error LNK1120: 7 unresolved externals [Project Path] 1 1 Many thanks!

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  • How to get compatibility between C# and SQL2k8 AES Encryption?

    - by Victor Rodrigues
    I have an AES encryption being made on two columns: one of these columns is stored at a SQL Server 2000 database; the other is stored at a SQL Server 2008 database. As the first column's database (2000) doesn't have native functionality for encryption / decryption, we've decided to do the cryptography logic at application level, with .NET classes, for both. But as the second column's database (2008) allow this kind of functionality, we'd like to make the data migration using the database functions to be faster, since the data migration in SQL 2k is much smaller than this second and it will last more than 50 hours because of being made at application level. My problem started at this point: using the same key, I didn't achieve the same result when encrypting a value, neither the same result size. Below we have the full logic in both sides.. Of course I'm not showing the key, but everything else is the same: private byte[] RijndaelEncrypt(byte[] clearData, byte[] Key) { var memoryStream = new MemoryStream(); Rijndael algorithm = Rijndael.Create(); algorithm.Key = Key; algorithm.IV = InitializationVector; var criptoStream = new CryptoStream(memoryStream, algorithm.CreateEncryptor(), CryptoStreamMode.Write); criptoStream.Write(clearData, 0, clearData.Length); criptoStream.Close(); byte[] encryptedData = memoryStream.ToArray(); return encryptedData; } private byte[] RijndaelDecrypt(byte[] cipherData, byte[] Key) { var memoryStream = new MemoryStream(); Rijndael algorithm = Rijndael.Create(); algorithm.Key = Key; algorithm.IV = InitializationVector; var criptoStream = new CryptoStream(memoryStream, algorithm.CreateDecryptor(), CryptoStreamMode.Write); criptoStream.Write(cipherData, 0, cipherData.Length); criptoStream.Close(); byte[] decryptedData = memoryStream.ToArray(); return decryptedData; } This is the SQL Code sample: open symmetric key columnKey decryption by password = N'{pwd!!i_ll_not_show_it_here}' declare @enc varchar(max) set @enc = dbo.VarBinarytoBase64(EncryptByKey(Key_GUID('columnKey'), 'blablabla')) select LEN(@enc), @enc This varbinaryToBase64 is a tested sql function we use to convert varbinary to the same format we use to store strings in the .net application. The result in C# is: eg0wgTeR3noWYgvdmpzTKijkdtTsdvnvKzh+uhyN3Lo= The same result in SQL2k8 is: AI0zI7D77EmqgTQrdgMBHAEAAACyACXb+P3HvctA0yBduAuwPS4Ah3AB4Dbdj2KBGC1Dk4b8GEbtXs5fINzvusp8FRBknF15Br2xI1CqP0Qb/M4w I just didn't get yet what I'm doing wrong. Do you have any ideas? EDIT: One point I think is crucial: I have one Initialization Vector at my C# code, 16 bytes. This IV is not set at SQL symmetric key, could I do this? But even not filling the IV in C#, I get very different results, both in content and length.

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  • linked list elements gone?

    - by Hristo
    I create a linked list dynamically and initialize the first node in main(), and I add to the list every time I spawn a worker process. Before the worker process exits, I print the list. Also, I print the list inside my sigchld signal handler. in main(): head = NULL; tail = NULL; // linked list to keep track of worker process dll_node_t *node; node = (dll_node_t *) malloc(sizeof(dll_node_t)); // initialize list, allocate memory append_node(node); node->pid = mainPID; // the first node is the MAIN process node->type = MAIN; in a fork()'d process: // add to list dll_node_t *node; node = (dll_node_t *) malloc(sizeof(dll_node_t)); append_node(node); node->pid = mmapFileWorkerStats->childPID; node->workerFileName = mmapFileWorkerStats->workerFileName; node->type = WORK; functions: void append_node(dll_node_t *nodeToAppend) { /* * append param node to end of list */ // if the list is empty if (head == NULL) { // create the first/head node head = nodeToAppend; nodeToAppend->prev = NULL; } else { tail->next = nodeToAppend; nodeToAppend->prev = tail; } // fix the tail to point to the new node tail = nodeToAppend; nodeToAppend->next = NULL; } finally... the signal handler: void chld_signalHandler() { dll_node_t *temp1 = head; while (temp1 != NULL) { printf("2. node's pid: %d\n", temp1->pid); temp1 = temp1->next; } int termChildPID = waitpid(-1, NULL, WNOHANG); dll_node_t *temp = head; while (temp != NULL) { if (temp->pid == termChildPID) { printf("found process: %d\n", temp->pid); } temp = temp->next; } return; } Is it true that upon the worker process exiting, the SIGCHLD signal handler is triggered? If so, that would mean that after I print the tree before exiting, the next thing I do is in the signal handler which is print the tree... which would mean i would print the tree twice? But the tree isn't the same. The node I add in the worker process doesn't exist when I print in the signal handler or at the very end of main(). Any idea why? Thanks, Hristo

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  • Strange behavior of move with strings

    - by Umair Ahmed
    I am testing some enhanced string related functions with which I am trying to use move as a way to copy strings around for faster, more efficient use without delving into pointers. While testing a function for making a delimited string from a TStringList, I encountered a strange issue. The compiler referenced the bytes contained through the index when it was empty and when a string was added to it through move, index referenced the characters contained. Here is a small downsized barebone code sample:- unit UI; interface uses System.SysUtils, System.Types, System.UITypes, System.Rtti, System.Classes, System.Variants, FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs, FMX.Layouts, FMX.Memo; type TForm1 = class(TForm) Results: TMemo; procedure FormCreate(Sender: TObject); end; var Form1: TForm1; implementation {$R *.fmx} function StringListToDelimitedString ( const AStringList: TStringList; const ADelimiter: String ): String; var Str : String; Temp1 : NativeInt; Temp2 : NativeInt; DelimiterSize : Byte; begin Result := ' '; Temp1 := 0; DelimiterSize := Length ( ADelimiter ) * 2; for Str in AStringList do Temp1 := Temp1 + Length ( Str ); SetLength ( Result, Temp1 ); Temp1 := 1; for Str in AStringList do begin Temp2 := Length ( Str ) * 2; // Here Index references bytes in Result Move ( Str [1], Result [Temp1], Temp2 ); // From here the index seems to address characters instead of bytes in Result Temp1 := Temp1 + Temp2; Move ( ADelimiter [1], Result [Temp1], DelimiterSize ); Temp1 := Temp1 + DelimiterSize; end; end; procedure TForm1.FormCreate(Sender: TObject); var StrList : TStringList; Str : String; begin // Test 1 : StringListToDelimitedString StrList := TStringList.Create; Str := ''; StrList.Add ( 'Hello1' ); StrList.Add ( 'Hello2' ); StrList.Add ( 'Hello3' ); StrList.Add ( 'Hello4' ); Str := StringListToDelimitedString ( StrList, ';' ); Results.Lines.Add ( Str ); StrList.Free; end; end. Please devise a solution and if possible, some explanation. Alternatives are welcome too.

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  • Consolidating coding styles: Funcs, private method, single method classes

    - by jdoig
    Hi all, We currently have 3 devs with, some, conflicting styles and I'm looking for a way to bring peace to the kingdom... The Coders: Foo 1: Likes to use Func's & Action's inside public methods. He uses actions to alias off lengthy method calls and Func's to perform simple tasks that can be expressed in 1 or 2 lines and will be used frequently through out the code Pros: The main body of his code is succinct and very readable, often with only one or 2 public methods per class and rarely any private methods. Cons: The start of methods contain blocks of lambda rich code that other developers don't enjoy reading; and, on occasion, can contain higher order functions that other dev's REALLY don't like reading. Foo 2: Likes to create a private method for (almost) everything the public method will have to do . Pros: Public methods remain small and readable (to all developers). Cons: Private methods are numerous. With private methods that call into other private methods, that call into... etc, etc. Making code hard to navigate. Foo 3: Likes to create a public class with a, single, public method for every, non-trivial, task that needs performing, then dependency inject them into other objects. Pros: Easily testable, easy to understand (one object, one responsibility). Cons: project gets littered by classes, opening multiple class files to understand what code does makes navigation awkward. It would be great to take the best of all these techniques... Foo-1 Has really nice, readable (almost dsl-like) code... for the most part, except for all the Action and Func lambda shenanigans bulked together at the start of a method. Foo-3 Has highly testable and extensible code that just feels a bit "belt-&-braces" for some solutions and has some code-navigation niggles (constantly hitting F12 in VS and opening 5 other .cs files to find out what a single method does). And Foo-2... Well I'm not sure I like anything about the one-huge .cs file with 2 public methods and 12 private ones, except for the fact it's easier for juniors to dig into. I admit I grossly over-simplified the explanations of those coding styles; but if any one knows of any patterns, practices or diplomatic-manoeuvres that can help unite our three developers (without just telling any of them to just "stop it!") that would be great. From a feasibility standpoint : Foo-1's style meets with the most resistance due to some developers finding lambda and/or Func's hard to read. Foo-2's style meets with a less resistance as it's just so easy to fall into. Foo-3's style requires the most forward thinking and is difficult to enforce when time is short. Any ideas on some coding styles or conventions that can make this work?

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  • Actionscript base class in Flex AIR app

    - by Alan
    I'm trying to build a Flex AIR app using Flex Builder 3, which I'm just getting started with. In Flash CS4, there's a text field in the authoring environment where you can specify a class that will become the "base" class - your class inherits from Sprite and then "becomes" the Stage at runtime. Is there a a way to do the same thing with Flex/AIR? Failing that, can anyone explain how to create and use an external class? Originally I had this in TestApp.mxml: <?xml version="1.0" encoding="utf-8"?> <mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:Script source="TestApp.as"/> </mx:WindowedApplication> And this in TestApp.as: package { public class TestApp { public function TestApp() { trace('Hello World'); } } } That gives the error "packages cannot be nested", so I tried taking out the package statement: public class TestApp { public function TestApp() { trace('Hello World'); } } That gives an error "classes cannot be nested", so I finally gave up and tried to take out the class altogether, figuring I'd try to start with a bunch of functions instead: function init() { trace('Hello World'); } But that gives the error "A file found in a source-path must have an externally visible definition. If a definition in the file is meant to be externally visible, please put the definition in a package". I can't win! When I put my class in a package, it says I can't do that because it would be nested. When I don't, it says it needs to be in a package so it can be seen. Does anyone know how to fix this? If I can't do the custom-class-as-base-class thing, is there a way I could just have it like: <?xml version="1.0" encoding="utf-8"?> <mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:Script source="TestApp.as"/> <mx:Script> var app = new TestApp(); </mx:Script> </mx:WindowedApplication> At the moment I can't import the class definition at all, so even that won't work. Thanks in advance!

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  • NewBie Question, jQuery: How can we implement if...else logic and call function

    - by Rachel
    I am new to jQuery and so don't mind this question if it sounds stupid but here is something that I am trying to do : I have 3 functions like: AddToCart Function which adds item to the shopping cart: //offer_id is the offer which we are trying to add to cart. addToCart: function(offer_id) { this.submit({action: 'add', 'offer_id': offer_id}, {'app_server_url': this.app_server_url}); }, RemoveFromCart which removes data from the cart //target is link clicked and event is the click event. removeFromCart: function(target, event) { this.uniqueElmt('cart_table').find('.sb_item_remove').unbind('click'); var offer_id = $(target).parent().find('.offer_id').html(); this.submit({action: 'remove', 'offer_id': offer_id, 'next_action': this.config.current_action}, {'app_server_url': this.app_server_url}); }, Get the current state of the cart //return string which represents current state of cart. getCartItems: function() { return this.contents; } Now I am trying to do 3 things: if there is no content in cart and addToCart is called than some action, so basically here we need to check the current state of cart and that is obtained by calling getCartItems and if it is Null and than if addToCart is called than we perform some action if there is content in the cart and addToCart is called than some action,so basically here we need to check the current state of cart and that is obtained by calling getCartItems and check if it is Null or not and than if addToCart is called than we perform some action if we had some content in the cart. if there is content in the cart and removeFromCart is called some action, so basically here we need to check the current state of cart and that is obtained by calling getCartItems and if it is not Null and if removeFromCart is called than we perform some action Pseudocode of what I am trying to do: if there is no content in cart and addToCart is called than $(document).track( { 'module' : 'Omniture', 'event' : 'instant', 'args' : { 'linkTrackVars' : 'products,events', 'linkTrackEvents' : 'scAdd,scOpen', 'linkType' : 'o', 'linkName' : 'Cart : First Product Added' // could be blank, but can include event name as added feature 'svalues' : { 'products' : ';OFFERID1[,;OFFERID2]', 'events' : 'scAdd,scOpen', }, } 'defer' : '0' } ); if there is content in the cart and addToCart is called than $(document).track( { 'module' : 'Omniture', 'event' : 'instant', 'args' : { 'linkTrackVars' : 'products,events', 'linkTrackEvents' : 'scAdd', 'linkType' : 'o', 'linkName' : 'Cart : Product Added' // could be blank, but can include event name as added feature 'svalues' : { 'products' : ';OFFERID1[,;OFFERID2]', 'events' : 'scAdd', }, }, 'defer' : '0' } ); if there is content in the cart and removeFromCart is called $(document).track( { 'module' : 'Omniture', 'event' : 'instant', 'args' : { 'linkTrackVars' : 'products,events', 'linkTrackEvents' : 'scRemove', 'linkType' : 'o', 'linkName' : 'Cart : Product Removed' // could be blank, but can include event name as added feature 'svalues' : { 'products' : ';OFFERID1[,;OFFERID2]', 'events' : 'scRemove', }, } 'defer' : '0' } ); My basic concern is that am complete newbie to jQuery and JavaScript and so am not sure how can I implement if...else logic and how can I call a funtion using jQuery/JavaScript.

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  • Performance of looping over an Unboxed array in Haskell

    - by Joey Adams
    First of all, it's great. However, I came across a situation where my benchmarks turned up weird results. I am new to Haskell, and this is first time I've gotten my hands dirty with mutable arrays and Monads. The code below is based on this example. I wrote a generic monadic for function that takes numbers and a step function rather than a range (like forM_ does). I compared using my generic for function (Loop A) against embedding an equivalent recursive function (Loop B). Having Loop A is noticeably faster than having Loop B. Weirder, having both Loop A and B together is faster than having Loop B by itself (but slightly slower than Loop A by itself). Some possible explanations I can think of for the discrepancies. Note that these are just guesses: Something I haven't learned yet about how Haskell extracts results from monadic functions. Loop B faults the array in a less cache efficient manner than Loop A. Why? I made a dumb mistake; Loop A and Loop B are actually different. Note that in all 3 cases of having either or both Loop A and Loop B, the program produces the same output. Here is the code. I tested it with ghc -O2 for.hs using GHC version 6.10.4 . import Control.Monad import Control.Monad.ST import Data.Array.IArray import Data.Array.MArray import Data.Array.ST import Data.Array.Unboxed for :: (Num a, Ord a, Monad m) => a -> a -> (a -> a) -> (a -> m b) -> m () for start end step f = loop start where loop i | i <= end = do f i loop (step i) | otherwise = return () primesToNA :: Int -> UArray Int Bool primesToNA n = runSTUArray $ do a <- newArray (2,n) True :: ST s (STUArray s Int Bool) let sr = floor . (sqrt::Double->Double) . fromIntegral $ n+1 -- Loop A for 4 n (+ 2) $ \j -> writeArray a j False -- Loop B let f i | i <= n = do writeArray a i False f (i+2) | otherwise = return () in f 4 forM_ [3,5..sr] $ \i -> do si <- readArray a i when si $ forM_ [i*i,i*i+i+i..n] $ \j -> writeArray a j False return a primesTo :: Int -> [Int] primesTo n = [i | (i,p) <- assocs . primesToNA $ n, p] main = print $ primesTo 30000000

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  • How do I get the next token in a Cstring if I want to use it as an int? (c++)

    - by Van
    My objective is to take directions from a user and eventually a text file to move a robot. The catch is that I must use Cstrings(such as char word[];) rather than the std::string and tokenize them for use. the code looks like this: void Navigator::manualDrive() { char uinput[1]; char delim[] = " "; char *token; cout << "Enter your directions below: \n"; cin.ignore(); cin.getline (uinput, 256); token=strtok(uinput, delim); if(token == "forward") { int inches; inches=token+1; travel(inches); } } I've never used Cstrings I've never tokenized anything before, and I don't know how to write this. Our T.A.'s expect us to google and find all the answers because they are aware we've never been taught these methods. Everyone in my lab is having much more trouble than usual. I don't know the code to write but I know what I want my program to do. I want it to execute like this: 1) Ask for directions. 2) cin.getline the users input 3) tokenize the inputed string 4) if the first word token == "forward" move to the next token and find out how many inches to move forward then move forward 5) else if the first token == "turn" move to the next token. if the next token == "left" move to the next token and find out how many degrees to turn left I will have to do this for forward x, backward x, turn left x, turn right x, and stop(where x is in inches or degrees). I already wrote functions that tell the robot how to move forward an inch and turn in degrees. I just need to know how to convert the inputted strings to all lowercase letters and move from token to token and convert or extract the numbers from the string to use them as integers. If all is not clear you can read my lab write up at this link: http://www.cs.utk.edu/~cs102/robot_labs/Lab9.html If anything is unclear please let me know, and I will clarify as best I can.

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  • C++ Class Templates (Queue of a class)

    - by Dalton Conley
    Ok, so I have my basic linked Queue class with basic functions such as front(), empty() etc.. and I have transformed it into a template. Now, I also have a class called Student. Which holds 2 values: Student name and Student Id. I can print out a student with the following code.. Student me("My Name", 2); cout << me << endl; Here is my display function for student: void display(ostream &out) const { out << "Student Name: " << name << "\tStudent Id: " << id << "\tAddress: " << this << endl; } Now it works fine, you can see the basic output. Now I'm declaring a queue like so.. Queue<Student> qstu; Storing data in this queue is fine, I can add new values and such.. now what I'm trying to do is print out my whole queue of students with: cout << qstu << endl; But its simply returning an address.. here is my display function for queues. void display(ostream & out) const { NodePointer ptr; ptr = myFront; while(ptr != NULL) { out << ptr->data << " "; ptr = ptr->next; } out << endl; } Now, based on this, I assume ptr-data is a Student type and I would assume this would work, but it doesn't. Is there something I'm missing? Also, when I Try: ptr->data.display(out); (Making the assumtion ptr-data is of type student, it does not work which tells me I am doing something wrong. Help on this would be much appreciated!

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  • The Math of a Jump in a 2D game.

    - by ONi
    I have been all around with this question and I can't find the correct answer! So, behold, the description of my question: I'm working in J2ME, I have my gameloop that do the following: public void run() { Graphics g = this.getGraphics(); while (running) { long diff = System.currentTimeMillis() - lastLoop; lastLoop = System.currentTimeMillis(); input(); this.level.doLogic(); render(g, diff); try { Thread.sleep(10); } catch (InterruptedException e) { stop(e); } } } so it's just a basic gameloop, the doLogic() function calls for all the logic functions of the characters in the scene and render(g, diff) calls the animateChar function of every character on scene, following this, the animChar function in the Character class sets up everything in the screen as this: protected void animChar(long diff) { this.checkGravity(); this.move((int) ((diff * this.dx) / 1000), (int) ((diff * this.dy) / 1000)); if (this.acumFrame > this.framerate) { this.nextFrame(); this.acumFrame = 0; } else { this.acumFrame += diff; } } This ensures me that everything must to move according to the time that the machine takes to go from cycle to cycle (remember it's a phone, not a gaming rig). I'm sure it's not the most efficient way to achieve this behavior so I'm totally open for criticism of my programming skills in the comments, but here my problem: When I make I character jump, what I do is that I put his dy to a negative value, say -200 and I set the boolean jumping to true, that makes the character go up, and then I have this function called checkGravity() that ensure that everything that goes up has to go down, checkGravity also checks for the character being over platforms so I will strip it down a little for the sake of your time: public void checkGravity() { if (this.jumping) { this.jumpSpeed += 10; if (this.jumpSpeed > 0) { this.jumping = false; this.falling = true; } this.dy = this.jumpSpeed; } if (this.falling) { this.jumpSpeed += 10; if (this.jumpSpeed > 200) this.jumpSpeed = 200; this.dy = this.jumpSpeed; if (this.collidesWithPlatform()) { this.falling = false; this.standing = true; this.jumping = false; this.jumpSpeed = 0; this.dy = this.jumpSpeed; } } } So, the problem is, that this function updates the dy regardless of the diff, making the characters fly like Superman in slow machines, and I have no idea how to implement the diff factor so that when a character is jumping, his speed decrement in a proportional way to the game speed. Can anyone help me fix this issue? or give me pointers on how to make a 2D Jump in J2ME the right way. Thank you very much for your time.

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  • Magento: add product twice to cart, with different attributes!

    - by Peter
    Hello all, i have been working with this for a whole day but i cannot find any solution: I have a product (lenses), which has identical attributes, but user can choose one attribute set for one eye and another attribute set for another. On the frontend i got it ok, see it here: http://connecta.si/clarus/index.php/featured/acuvue-oasys-for-astigmatism.html So the user can select attributes for left or right eye, but it is the same product. I build a function, wich should take a product in a cart (before save), add other set of attributes, so there should be two products in the cart. What happens is there are two products, but with the same set of attributes??? Here is the snippet of the function: $req = Mage::app()-getRequest(); $request[’qty’] = 1; $request[’product’] = 15; $request[’uenc’] = $req-get(’uenc’); $request[’options’][1] = 1; $request[’options’][3] = 5; $request[’options’][2] = 3; $reqo = new Varien_Object($request); $newitem = $quote-addProduct($founditem-getProduct(), $reqo); //add another one ------------------------------------------ $request[’qty’] = 1; $request[’product’] = 15; $request[’uenc’] = $req-get(’uenc’); $request[’options’][1] = 2; $request[’options’][3] = 6; $request[’options’][2] = 4; $reqo = new Varien_Object($request); $newitem = $quote-addProduct($founditem-getProduct(), $reqo); Or another test, with some other functions (again, product added, with 2 quantity , but same attributes...): $req = Mage::app()-getRequest(); $request[’qty’] = 1; $request[’product’] = 15; $request[’uenc’] = $req-get(’uenc’); $request[’options’][1] = 2; $request[’options’][3] = 6; $request[’options’][2] = 4; $product = $founditem-getProduct(); $cart = Mage::getSingleton(’checkout/cart’); //delete all first… $cart-getItems()-clear()-save(); $reqo = new Varien_Object($request); $cart-addProduct($founditem-getProduct(), $reqo); $cart-getItems()-save(); $request[’options’][1] = 1; $request[’options’][3] = 5; $request[’options’][2] = 3; $reqo = new Varien_Object($request); $cart-addProduct($founditem-getProduct(), $reqo); $cart-getItems()-save(); i really dont know what more to do, please any advice, this is my first module in magento… thank you, Peter

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  • How to apply or chain multiple matching templates in XSLT?

    - by Ignatius
    I am working on a stylesheet employing many templates with match attributes: <xsl:template match="//one" priority="0.7"> <xsl:param name="input" select="."/> <xsl:value-of select="util:uppercase($input)"/> <xsl:next-match /> </xsl:template> <xsl:template match="/stuff/one"> <xsl:param name="input" select="."/> <xsl:value-of select="util:add-period($input)"/> </xsl:template> <xsl:function name="util:uppercase"> <xsl:param name="input"/> <xsl:value-of select="upper-case($input)"/> </xsl:function> <xsl:function name="util:add-period"> <xsl:param name="input"/> <xsl:value-of select="concat($input,'.')"/> </xsl:function> What I would like to do is be able to 'chain' the two functions above, so that an input of 'string' would be rendered in the output as 'STRING.' (with the period.) I would like to do this in such a way that doesn't require knowledge of other templates in any other template. So, for instance, I would like to be able to add a "util:add-colon" method without having to open up the hood and monkey with the existing templates. I was playing around with the <xsl:next-match/> instruction to accomplish this. Adding it to the first template above does of course invoke both util:uppercase and util:add-period, but the output is an aggregation of each template output (i.e. 'STRINGstring.') It seems like there should be an elegant way to chain any number of templates together using something like <xsl:next-match/>, but have the output of each template feed the input of the next one in the chain. Am I overlooking something obvious?

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  • How to drop null values with a native Oracle XML DB Web Service?

    - by gfjr
    I am using native Oracle XML DB Web Services (using a PL/SQL function with a web service). I want to drop null values (put nothing in the output (no XML element)). It's working with Oracle 11.2.0.1.0 but not with Oracle 11.2.0.3.0. Just to clarify... I don't want to consume a webservice with PL/SQL, I want to publish my PL/SQL packages/procedures/functions as a web service! Hope someone can help me. Thank you. In this example is the column "country" null. Oracle 11.2.0.1.0 (this is what I want): <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <GET_PERSONOutput xmlns="http://xmlns.oracle.com/orawsv/TESTSTUFF/GET_PERSON"> <RETURN> <PERSON> <PERSON_ID>3</PERSON_ID> <FIRST_NAME>Harry</FIRST_NAME> <LAST_NAME>Potter</LAST_NAME> </PERSON> </RETURN> </GET_PERSONOutput> </soap:Body> </soap:Envelope> Oracle 11.2.0.3.0: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <GET_PERSONOutput xmlns="http://xmlns.oracle.com/orawsv/TESTSTUFF/GET_PERSON"> <RETURN> <PERSON> <PERSON_ID>3</PERSON_ID> <FIRST_NAME>Harry</FIRST_NAME> <LAST_NAME>Potter</LAST_NAME> <COUNTRY/> </PERSON> </RETURN> </GET_PERSONOutput> </soap:Body> </soap:Envelope>

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  • Error Handling for Application in PHP

    - by Zubair1
    I was wondering if someone can show me a good way to handle errors in my PHP app, that i am also easily able to reuse in my codes. So far i have been using the following functions: Inline Errors function display_errors_for($fieldname) { global $errors; if (isset($errors[$fieldname])) { return '<label for="' .$fieldname. '" class="error">' . ucfirst($errors[$fieldname]). '</label>'; } else { return false; } } All Errrors function display_all_errors($showCounter = true) { global $errors; $counter = 0; foreach ($errors as $errorFieldName => $errorText) { if ($showCounter == true) { $counter++; echo '<li>' . $counter . ' - <label for="' .$errorFieldName. '">' .$errorText. '</label></li>'; } else { echo '<li><label for="' .$errorFieldName. '">' .$errorText. '</label></li>'; } } } I have a $errors = array(); defined on the top of my global file, so it is appended to all files. The way i use it is that if i encounter an error, i push a new error key/value to the $errors array holder, something like the following: if (strlen($username) < 3) { $errors['username'] = "usernames cannot be less then 3 characters."; } This all works great and all, But i wondering if some one has a better approach for this? with classes? i don't think i want to use Exceptions with try/catch seems like an overkill to me. I'm planning to make a new app, and i'll be getting my hands wet with OOP alot, though i have already made apps using OOP but this time i'm planning to go even deeper and use OOP approach more extensively. What i have in mind is something like this, though its just a basic class i will add further detail to it as i go deeper and deeper in my app to see what it needs. class Errors { public $errors = array(); public function __construct() { // Initialize Default Values // Initialize Methods } public function __destruct() { //nothing here too... } public function add($errorField, $errorDesc) { if (!is_string($errorField)) return false; if (!is_string($errorDesc)) return false; $this->errors[$errorField] = $errorDesc; } public function display($errorsArray) { // code to iterate through the array and display all errors. } } Please share your thoughts, if this is a good way to make a reusable class to store and display errors for an entire app, or is getting more familiar with exceptions and try/catch my only choice?

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  • WPF/C#: How to simplify the use of codes when calling a function (Generating Images)

    - by eibhrum
    I created a function in one of my application that allows to generate an image (in WPF) by getting the 'source path' from the database that I am using: public void ShowImageThumb() { try { cn = new MySqlConnection(); cn.ConnectionString = ConfigurationManager.AppSettings["MyConnection"]; cn.Open(); MySqlCommand cmd = new MySqlCommand(); cmd.Connection = cn; cmd.CommandType = CommandType.Text; cmd.CommandText = "SELECT thumb FROM album WHERE thumbNo=1"; MySqlDataAdapter adp = new MySqlDataAdapter(); adp.SelectCommand = cmd; DataTable dt = new DataTable(); adp.Fill(dt); MySqlDataReader r = cmd.ExecuteReader(); while (r.Read()) { BitmapImage bmi1 = new BitmapImage(new Uri(r[0].ToString(), UriKind.Relative)); image1.Source = bmi1; } r.Close(); cn.Close(); } catch (Exception err){ System.Windows.MessageBox.Show(err.Message); } finally { } } Take a look on my SQL statement. I put a WHERE thumbNo=1 which allows the function to get 1 record. You see, I do have at least 10 records - file paths listed in that table. I just wanna ask if there's a possible way to make my SQL statement something like this: SELECT thumb FROM album; while having this piece of code inserted in my function: BitmapImage bmi2 = new BitmapImage(new Uri(r["second record?"].ToString(), UriKind.Relative)); image2.Source = bmi2; //something like this BitmapImage bmi3 = new BitmapImage(new Uri(r["third record?"].ToString(), UriKind.Relative)); image3.Source = bmi3; //something like this and so on and so forth, without ending up creating 10 different functions for 10 records. ShowImageThumb2(); . . // will not do this . ShowImageThumb10(); Sorry for the lengthy post. I hope somebody could answer back. Thanks!

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