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• handle large Parcelable ArrayList in Android

  - by Gal Ben-Haim

  I'm developing an Android app that is a client to a JSON webservice API. I have classes of resource objects (some are nested) and I pass results from an IntentService that access the webserive using the Parcelable interface for all the resource classes. the webservice returns arrays or results that can be potentially large (because of the nesting, for example, a post object also contains comments array, each comment also contains a user object). currently I'm either inserting the results into a SQlite database or displaying them in a ListView. (my relevant methods are accepting ArrayList<resourceClass> as arguments). (some data need to be persistent stored and some should not). since I don't know what size of lists I can handle this way without reaching the memory limits, is this a good practice ? is it a better idea to save the parsed JSON to a local file immediately and pass the file path to the ResultReceiver, then either insert to database from that file or display the data ? is there a better way to handle this ? btw - I'm parsing the JSON as a stream with Gson's Reader so there shouldn't be memory issues at that stage.

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• Animation is slow on iPhone

  - by Anthony Chan

  I'm developing an app that would display images and change them according to the user's action. I've created a subclass of UIView to contain an image, an index number and an array of image names. The code is like this: @interface CustomPic : UIView { UIImageView *pic; NSInteger index; NSMutableArray *picNames; //<-- an array of NSString } And in the implementation part, it has a method to change the image using a dissolve effect. - (void)nextPic { index++; if (index >= [picNames count]) { index = 0; } UIImageView *temp = pic; pic.image = [UIImage imageNamed:[picNames objectAtIndex:index]]; temp.alpha = 0; [UIView beginAnimations:nil context:nil]; [UIView setAnimationCurve:UIViewAnimationCurveEaseOut]; [UIView setAnimationDuration:0.25]; pic.alpha = 0; temp.alpha = 1; [UIView commitAnimations]; } In the viewController, there are several CustomPic which would change the images depends on users' choice. The images would change as expected with the fade in/out effect, but the animation performance is really bad. I've tested it on an iPhone 3G, the Instruments shows that the animation is only 2-3FPS! I tried many methods to simplify and modify the codes but with no hope. Is there something wrong in my code or in my concept? Thanks for any help. P.S. all the images are 320*480 PNGs with a max size of 15KB.

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• How do you pass a generic delegate argument to a method in .NET 2.0 - UPDATED

  - by Seth Spearman

  Hello, I have a class with a delegate declaration as follows... Public Class MyClass Public Delegate Function Getter(Of TResult)() As TResult ''#the following code works. Public Shared Sub MyMethod(ByVal g As Getter(Of Boolean)) ''#do stuff End Sub End Class However, I do not want to explicitly type the Getter delegate in the Method call. Why can I not declare the parameter as follows... ... (ByVal g As Getter(Of TResult)) Is there a way to do it? My end goal was to be able to set a delegate for property setters and getters in the called class. But my reading indicates you can't do that. So I put setter and getter methods in that class and then I want the calling class to set the delegate argument and then invoke. Is there a best practice for doing this. I realize in the above example that I can set set the delegate variable from the calling class...but I am trying to create a singleton with tight encapsulation. For the record, I can't use any of the new delegate types declared in .net35. Answers in C# are welcome. Any thoughts? Seth

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• ResourceFilterFactory and non-Path annotated Resources

  - by tousdan

  (I'm using Jersey 1.7) I am attempting to add a ResourceFilterFactory in my project to select which filters are used per method using annotations. The ResourceFilterFactory seems to be able to filters on Resources which are annotated with the Path annotation but it would seem that it does not attempt to generate filters for the methods of the SubResourceLocator of the resources that are called. @Path("a") public class A { //sub resource locator? @Path("b") public B getB() { return new B(); } @GET public void doGet() {} } public class B { @GET public void doOtherGet() { } @Path("c") public void doInner() { } } When ran, the Filter factory will only be called for the following: AbstractResourceMethod(A#doGet) AbstractSubResourceLocator(A#getB) When I expected it to be called for every method of the sub resource. I'm currently using the following options in my web.xml; <init-param> <param-name>com.sun.jersey.spi.container.ResourceFilters</param-name> <param-value>com.my.MyResourceFilterFactory</param-value> </init-param> <init-param> <param-name>com.sun.jersey.config.property.packages</param-name> <param-value>com.my.resources</param-value> </init-param> Is my understanding of the filter factory flawed?

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• Skipping the BufferedReader readLine() method in java

  - by DDP

  Is there a easy way to skip the readLine() method in java if it takes longer than, say, 2 seconds? Here's the context in which I'm asking this question: public void run() { boolean looping = true; while(looping) { for(int x = 0; x<clientList.size(); x++) { try { Comm s = clientList.get(x); String str = s.recieve(); // code that does something based on the string in the line above } // other stuff like catch methods } } } Comm is a class I wrote, and the receive method, which contains a BufferedReader called "in", is this: public String recieve() { try { if(active) return in.readLine(); } catch(Exception e) { System.out.println("Comm Error 2: "+e); } return ""; } I've noticed that the program stops and waits for the input stream to have something to read before continuing. Which is bad, because I need the program to keep looping (as it loops, it goes to all the other clients and asks for input). Is there a way to skip the readLine() process if there's nothing to read? I'm also pretty sure that I'm not explaining this well, so please ask me questions if I'm being confusing.

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• Ext JS 4.2.1 loading controller - best practice

  - by Hown_

  I am currently developing a Ext JS application with many views/controlers/... I am wondering myself what the best practice is for loading the JS controllers/views/and so on... currently i have my application defined like this: // enable javascript cache for debugging, otherwise Chrome breakpoints are lost Ext.Loader.setConfig({ disableCaching: false }); Ext.require('Ext.util.History'); Ext.require('app.Sitemap'); Ext.require('app.Error'); Ext.define('app.Application', { name: 'app', extend: 'Ext.app.Application', views: [ // TODO: add views here 'app.view.Viewport', 'app.view.BaseMain', 'app.view.Main', 'app.view.ApplicationHeader', //administration 'app.view.administration.User' ... ], controllers: [ 'app.controller.Viewport', 'app.controller.Main', 'app.controller.ApplicationHeader', //administration 'app.controller.administration.User', ... ], stores: [ // stores in there.. ] }); somehow this forces the client to load all my views and controllers at startup and is calling all init methods of all controllers of course.. i need to load data everytime i chnage my view.. and now i cant load it in my controllers init function. I would have to do something like this i assume: init: function () { this.control({ '#administration_User': { afterrender: this.onAfterRender } }); }, Is there a better way to do this? Or just an other event? Though the main thing i am questioning myself is if it is the best practice to load all the javascript at startup. Wouldnt it be better to only load the controllers/views/... which the client does need right now? Or should i load all the JS at startup? If i do want to load the controllers dynamicly how could i do this? I assume a would have to remove them from my application arrays (views, controllers, stores) and create an instance if i do need it and mby set the view in the controllers init?! What's best practice??

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• Moving UIScrollView in App

  - by jsetting32

  Currently, I am attempting to create the same effect as Yahoo! Weather's App where the vital day information is at the bottom of the page on the top of a UIScrollView, that's contained by a UIView. I am having a hard time thinking about how this is going to happen or how I should implement this. If the user taps on the top of the UIScrollView which is located near the bottom of the laoded UIView, and starts to scroll up (/), the UIScrollView's frame should be moved to the TOP of the current UIView's frame. So the UIScrollView's y-value should change to UIView's (self.view.frame.origin.y) if the user starts scrolling UP on the UIScrollView which is located on the UIView's y-pixel ~280. Here's what the UIViewController should look like in the beginning of loading the ViewController... Then once the user slides his finger from the bottom to the top of the screen... this should happen........ And when the user scrolls to the top of the UIScrollView with all the content within it... the view should go back to the start picture shown... How is this done? I was thinking several UIGestureRecognizer's and Instantiating the UIscrollview at the lower part of the UIView... _weatherView = [[UIScrollView alloc] initWithFrame:CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y + 250, self.view.bounds.size.width, self.view.bounds.size.height - 44)]; _weatherView.contentSize = CGSizeMake(self.view.bounds.size.width, self.view.bounds.size.height * 4); _weatherView.backgroundColor = [UIColor clearColor]; [self.view addSubview:_weatherView]; The adding some UIGestureRecognizer delegate method.... But anyone have any ideas on the UIGestureRecognizer delegate method? And how it should be implemented? I can write the psuedo-code but I am having problems finding the delegate methods :P Thank you!!! ---- Break Time.... :)

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• Calling a function within a jQuery plug-in

  - by Bob Knothe

  I am in the process of creating my first jQuery plug-in that will format numbers automatically to various international formats. There are a couple functions within the plug-in that strips the strings and re-formats the string that needs to be called from another jQuery script. Based on the plug-in structure below (let me know if you need the entire code) can I call and send the parameter(s) to the stripFormat(ii) and targetFormat(ii, iv) functions? Or do I need to change my plug-in structure and if so how? (function($){ var p = $.extend({ aNum: '0123456789', aNeg: '-', aSep: ',', aDec: '.', aInput: '', cPos: 0 }); $.fn.extend({ AutoFormat: function() { return this.each(function() { $(this).keypress(function (e){ code here; }); $(this).keyup(function (e){ code here; }); // Would like to call this function from another jQuery script - see below. function stripFormat(ii){ code here; } // Would like to call this function from another jQuery script - see below. function targetFormat(ii, iv){ code here; } }); } }); })(jQuery); Methods trying to call the plug-in functions: jQuery(function(){ $("input").change(function (){ //temp function to demonstrate the stripFormat() function. document.getElementById(targetElementid).value = targetFormat(targetElementid, targetValue); }); }); I have tried to use these variations without success: document.getElementById(targetElementid).value = $.targetFormat(targetElementid, targetValue); document.getElementById(targetElementid).value = $.autoFormat().targetFormat(targetElementid, targetValue);

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• Rtti data manipulation and consistency in Delphi 2010

  - by Coco

  Has anyone an idea, how I can make TValue using a reference to the original data? In my serialization project, I use (as suggested in XML-Serialization) a generic serializer which stores TValues in an internal tree-structure (similar to the MemberMap in the example). This member-tree should also be used to create a dynamic setup form and manipulate the data. My idea was to define a property for the Data: TDataModel <T> = class {...} private FData : TValue; function GetData : T; procedure SetData (Value : T); public property Data : T read GetData write SetData; end; The implementation of the GetData, SetData Methods: procedure TDataModel <T>.SetData (Value : T); begin FData := TValue.From <T> (Value); end; procedure TDataModel <T>.GetData : T; begin Result := FData.AsType <T>; end; Unfortunately, the TValue.From method always makes a copy of the original data. So whenever the application makes changes to the data, the DataModel is not updated and vice versa if I change my DataModel in a dynamic form, the original data is not affected. Sure I could always use the Data property before and after changing anything, but as I use lot of Rtti inside my DataModel, I do not realy want to do this anytime. Perhaps someone has a better suggestion?

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• [iText] Inserting Image onCloseDocument

  - by David

  I'm trying to insert an image in the footer of my document using iText's onCloseDocument event. I have the following code: public void onCloseDocument(PdfWriter writer, Document document) { PdfContentByte pdfByte = writer.getDirectContent(); try { // logo is a non-null global variable Image theImage = new Jpeg(logo); pdfByte.addImage(theImage, 400.0f, 0.0f, 0.0f, 400.0f, 0.0f, 0.0f); } catch (Exception e) { e.printStackTrace(); } } The code throws no exceptions, but it also fails to insert the image. This identical code is used onOpenDocument to insert the same logo. The only difference between the two methods are the coordinates in pdfByte.addImage. However, I've tried quite a few different coordinations in onCloseDocument and none of them appear anywhere in my document. Is there any troubleshooting technique for detecting content which is displayed off-page in a PDF? If not, can anyone see the problem with my onCloseDocument method? Edit: As a followup, it seems that onDocumentClose puts its content on page document.length() + 1 (according to its API). However, I don't know how to change the page number back to document.length() and place my logo on the last page.

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• What does the windbg command "kd" do?

  - by Oskar

  I ran kd by mistake and got some output that inteerested me, a reference to a line of code in my module that I can't see on the call stack of any thread. The lines weren't the beginnning of the method so I don't think the reference is to a function pointer, but possibly the result of an exception being stored in memory??? Of course, that happens to be what I'm looking for... Update: The stack trace of the exception is: 0:000> kb *** Stack trace for last set context - .thread/.cxr resets it ChildEBP RetAddr Args to Child 0174f168 734ea84f 2cb9e950 00000000 2cb9e950 kernel32!LoadTimeZoneInformation+0x2b 0174f1c4 734ead92 00000022 00000001 000685d0 msvbvm60! RUN_INSTMGR::ExecuteInitTerm+0x178 0174f1f8 734ea9ee 00000000 0000002f 2dbc2abc msvbvm60! RUN_INSTMGR::CreateObjInstanceWithParts+0x1e4 0174f278 7350414e 2cb9e96c 00000000 0174f2f0 msvbvm60! RUN_INSTMGR::CreateObjInstance+0x14d 0174f2e4 734fa071 00000000 2cb9e96c 0174f2fc msvbvm60!RcmConstructObjectInstance+0x75 0174f31c 00976ef1 2cb9e950 00591bc0 0174fddc msvbvm60!__vbaNew+0x21 and into our code (create a new Form derived class) the dds output: 0:000> dds esp-0x40 esp+0x100 0174f05c 00000000 0174f060 00000000 0174f064 00000000 0174f068 00000000 0174f06c 00000000 0174f070 00000000 0174f074 00000000 0174f078 00000000 0174f07c 00000000 0174f080 00000000 0174f084 00000000 0174f088 00000000 0174f08c 00000000 0174f090 00000000 0174f094 00000000 0174f098 00000000 0174f09c 007f4f9b ourDll!formDerivedClass::Form_Initialize+0x10b [C:\Buildbox\formDerivedClass.frm @ 1452] etc which seems to indicate that Initialize is being called even though it isn't on the stack trace of either this exception or any of the threads. As suggested, it might all be a mismatch between pdbs and dlls, but it seems a coincidence that we end up in the right classes and methods

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• c# multi inheritance

  - by user326839

  So ive got a base class which requires a Socket: class Sock { public Socket s; public Sock(Socket s) { this.s = s; } public virtual void Process(byte[] data) { } ... } then ive got another class. if a new socket gets accepted a new instance of this class will be created: class Game : Sock { public Random Random = new Random(); public Timerr Timers; public Test Test; public Game(Socket s) : base(s) { } public static void ReceiveNewSocket(object s) { Game Client = new Game((Socket)s); Client.Start(); } public override void Process(byte[] buf) { Timers = new Timerr(s); Test = new Test(s); Test.T(); } } in the Sock class ive got a virtual function that gets overwritten by the Game class.(Process function) in this function im calling a function from the Test Class(Test+ Timerr Class: class Test : Game { public Test(Socket s) : base(s) { } public void T() { Console.WriteLine(Random.Next(0, 10)); Timers.Start(); } } class Timerr : Game { public Timerr(Socket s) : base(s) { } public void Start() { Console.WriteLine("test"); } } ) So in the Process function im calling a function in Test. And in this function(T) i need to call a function from the Timerr Class.But the problem is its always NULL , although the constructor is called in Process. And e.g. the Random Class can be called, i guess its because its defined with the constructor.: public Random Random = new Random(); and thats why the other classes(without a constructor): public Timerr Timers; public Test Test; are always null in the inherited class Test.But its essentiel that i call other Methods of other classes in this function.How could i solve that?

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• Register new memer for vBulletin via Mobile API

  - by Nikolay Stariradeff

  I'm trying to use the vBulletin REST Mobile API to simply register. The sourced are installed on my local machine and according the documentation https://www.vbulletin.com/forum/content.php/393-User-Registration-Process-Mobile-API This procedure should not be so hard, especially without humanity and COPPA authentication. However I've stacked! The method definition describes "addnewmember" clear, so I've generated a test link, which should do the job. https://www.vbulletin.com/forum/content.php/365-User-Related-Methods The link is: .../forum/api.php?&api_m=register_addmember&api_c=1&api_s=76ec9eec61e7fdfef2f3feee28d5f392&api_sig=8fe54313b333cc0fef4ddd8e398b5c80&api_v=6&agree=1&username=testuser&email=XXXXXX%40gmail.com&emailconfirm=XXXXX%40gmail.com&password=12345678&passwordconfirm=12345678 As a response I get: register_not_agreed The Docs: register_not_agreed The agree parameter should be set to 1. Which is also clear - agree parameter was not there. Here comes the funny part - In the API-Log I can see that the 'agree' parameter is correctly passed *1 test_client Gast 13:23, 18.06.2012 register_addmember Array ( [api_m] = register_addmember [api_c] = 1 [api_s] = 76ec9eec61e7fdfef2f3feee28d5f392 [api_sig] = 8fe54313b333cc0fef4ddd8e398b5c80 [api_v] = 6 [agree] = 1 [username] = testuser [email] = ....* Is there anybody with experience with the Mobile API that could help?

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• eclipse show errors but compiles when external makefile

  - by Anthony

  I have some c++ code using CImg and Eigen libraries. At the c++ code I define a plugin like this #define cimg_plugin1 "my_plugin.h" #include "CImg.h" The plugin contains many method definitions that are used at the c++ code. I also have a makefile that when called from the command line (./make), allows me to compile everything, and generates an executable. I want to import this code into a new Eclipse project, and I do it so: NewProjectC++ projectmakefile projectempty project unmark "Use default location", and select the folder containing my code at the filesystem ProjectpropertiesC/C++ Buildunmark "Use default build command" and set it to use my makefile Also in project propertiesC/C++ GeneralPaths and SymbolsAdd paths to folders containing Eigen and CImg Rebuild index Clean project Restart eclipse When I build the project, eclipse tells me I have more than 1000 errors in "my_plugin.h", but it is capable to generate the executable. Even though, I would like to get rid of this errors, because they are annoying. Also, if I want to open the declaration of CImg methods used at the plugin, I can't. I know it has been asked before, but any of the solutions I found were satisfactory for me (most of them enumerated at the previous list). The sources I visited are the following, and I would be really happy if you find and tell me others I didn't see. Eclipse shows errors but project compile fine eclipse C project shows errors (Symbol could not be resolved) but it compiles Eclipse CDT shows some errors, but the project is successfully built http://www.eclipse.org/forums/index.php/t/247954/

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• Page Render Time in ASP.MVC in trace

  - by Pankaj

  Hello Everyone I want to check render time of each page in asp.net mvc application. i am using asp.net tracing. i have override the OnActionExecuting and OnActionExecuted methods on the BaseController class. protected override void OnActionExecuting(ActionExecutingContext filterContext) { string controler = filterContext.RouteData.Values["controller"].ToString(); string action = filterContext.RouteData.Values["action"].ToString(); StartTime =System.DateTime.Now; System.Diagnostics.Trace.Write(string.Format("Start '{0}/{1}' on: {2}", controler, action, System.DateTime.Now.UtilToISOFormat())); } protected override void OnActionExecuted(ActionExecutedContext filterContext) { string controler = filterContext.RouteData.Values["controller"].ToString(); string action = filterContext.RouteData.Values["action"].ToString(); var totalTime = System.DateTime.Now - this.StartTime; System.Diagnostics.Trace.Write(totalTime.ToString()); System.Diagnostics.Trace.Write(string.Format("End '{0}/{1}' on: {2}", controler, action, System.DateTime.Now.UtilToISOFormat())); } in OnActionExecuted method i get total time. how can i show this time in my http://localhost:51335/Trace.axd report?

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• Few Basic Questions in Overriding

  - by Dahlia

  I have few problems with my basic and would be thankful if someone can clear this. What does it mean when I say base *b = new derived; Why would one go for this? We very well separately can create objects for class base and class derived and then call the functions accordingly. I know that this base *b = new derived; is called as Object Slicing but why and when would one go for this? I know why it is not advisable to convert the base class object to derived class object (because base class is not aware of the derived class members and methods). I even read in other StackOverflow threads that if this is gonna be the case then we have to change/re-visit our design. I understand all that, however, I am just curious, Is there any way to do this? class base { public: void f(){cout << "In Base";} }; class derived:public base { public: void f(){cout << "In Derived";} }; int _tmain(int argc, _TCHAR* argv[]) { base b1, b2; derived d1, d2; b2 = d1; d2 = reinterpret_cast<derived*>(b1); //gives error C2440 b1.f(); // Prints In Base d1.f(); // Prints In Derived b2.f(); // Prints In Base d1.base::f(); //Prints In Base d2.f(); getch(); return 0; } In case of my above example, is there any way I could call the base class f() using derived class object? I used d1.base()::f() I just want to know if there any way without using scope resolution operator? Thanks a lot for your time in helping me out!

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• Constructor Overloading

  - by Mark Baker

  Normally when I want to create a class constructor that accepts different types of parameters, I'll use a kludgy overloading principle of not defining any args in the constructor definition: e.g. for an ECEF coordinate class constructor, I want it to accept either $x, $y and $z arguments, or to accept a single array argument containg x, y and z values, or to accept a single LatLong object I'd create a constructor looking something like: function __construct() { // Identify if any arguments have been passed to the constructor if (func_num_args() > 0) { $args = func_get_args(); // Identify the overload constructor required, based on the datatype of the first argument $argType = gettype($args[0]); switch($argType) { case 'array' : // Array of Cartesian co-ordinate values $overloadConstructor = 'setCoordinatesFromArray'; break; case 'object' : // A LatLong object that needs converting to Cartesian co-ordinate values $overloadConstructor = 'setCoordinatesFromLatLong'; break; default : // Individual Cartesian co-ordinate values $overloadConstructor = 'setCoordinatesFromXYZ'; break; } // Call the appropriate overload constructor call_user_func_array(array($this,$overloadConstructor),$args); } } // function __construct() I'm looking at an alternative: to provide a straight constructor with $x, $y and $z as defined arguments, and to provide static methods of createECEFfromArray() and createECEFfromLatLong() that handle all the necessary extraction of x, y and z; then create a new ECEF object using the standard constructor, and return that Which option is cleaner from an OO purists perspective?

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• ASP:GridView does not show data with ObjectdataSource

  - by Kashif

  I have been trying to bind a DataGrid with ObjectDataSource having custom paging but no output is display on my usercontrol. Here is the code I am using <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="LeadId" DataSourceID="dsBuyingLead1" AllowPaging="True"> <Columns> <asp:BoundField DataField="Subject" HeaderText="Subject" ReadOnly="True" /> <asp:BoundField DataField="ExpiryDate" HeaderText="ExpiryDate" ReadOnly="True" /> </Columns> </asp:GridView> <asp:ObjectDataSource ID="dsBuyingLead1" runat="server" EnablePaging="True" DataObjectTypeName="Modules.SearchBuyingLeadInfo" OldValuesParameterFormatString="original_{0}" SelectMethod="GetAllBuyingLeads" StartRowIndexParameterName="startRow" MaximumRowsParameterName="maximumRows" SelectCountMethod="GetAllBuyingLeadsCount" TypeName="Modules.SearchController"> <SelectParameters> <asp:QueryStringParameter Name="searchText" QueryStringField="q" Type="String" /> </SelectParameters> </asp:ObjectDataSource> Here are my methods from SearchController class: [DataObjectMethod(DataObjectMethodType.Select)] public static long GetAllBuyingLeadsCount(string searchText) { return DataProvider.Instance().GetAllBuyingLeadsCount(searchText); } [DataObjectMethod(DataObjectMethodType.Select)] public static List<SearchBuyingLeadInfo> GetAllBuyingLeads (string searchText, int startRow, int maximumRows) { List<SearchBuyingLeadInfo> l = CBO.FillCollection<SearchBuyingLeadInfo> ( DataProvider.Instance() .GetAllBuyingLeadswithText(searchText, startRow, maximumRows) ); return l; } Where SearchBuyingLeadInfo is my Data Access Object class I have verified by setting up break points that both GetAllBuyingLeadsCount and GetAllBuyingLeads return non-zero values but unfortunately nothing is displayed on the grid. Only the column headers are displayed. Can anyone tell me what am I missing?

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• Strongly Typed DataSet column requires custom type to implement IXmlSerializable?

  - by Phil

  I have a strongly typed Dataset with a single table with three columns. These columns all contain custom types. DataColumn1 is of type Parent DataColumn2 is of type Child1 DataColumn3 is of type Child2 Here is what these classes look like: [Serializable] [XmlInclude(typeof(Child1)), XmlInclude(typeof(Child2))] public abstract class Parent { public int p1; } [Serializable] public class Child1 :Parent { public int c1; } [Serializable] public class Child2 : Parent { public int c1; } now, if I add a row with DataColumn1 being null, and DataColumns 2 and 3 populated and try to serialize it, it works: DataSet1 ds = new DataSet1(); ds.DataTable1.AddDataTable1Row(null, new Child1(), new Child2()); StringBuilder sb = new StringBuilder(); using (StringWriter writer = new StringWriter(sb)) { ds.WriteXml(writer);//Works! } However, if I try to add a value to DataColumn1, it fails: DataSet1 ds = new DataSet1(); ds.DataTable1.AddDataTable1Row(new Child1(), new Child1(), new Child2()); StringBuilder sb = new StringBuilder(); using (StringWriter writer = new StringWriter(sb)) { ds.WriteXml(writer);//Fails! } Here is the Exception: "Type 'WindowsFormsApplication4.Child1, WindowsFormsApplication4, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' does not implement IXmlSerializable interface therefore can not proceed with serialization." I have also tried using the XmlSerializer to serialize the dataset, but I get the same exception. Does anyone know of a way to get around this where I don't have to implement IXmlSerializable on all the Child classes? Alternatively, is there a way to implement IXmlSerializable keeping all default behavior the same (ie not having any class specific code in the ReadXml and WriteXml methods)

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• Event feed implementation - will it scale?

  - by SlappyTheFish

  Situation: I am currently designing a feed system for a social website whereby each user has a feed of their friends' activities. I have two possible methods how to generate the feeds and I would like to ask which is best in terms of ability to scale. Events from all users are collected in one central database table, event_log. Users are paired as friends in the table friends. The RDBMS we are using is MySQL. Standard method: When a user requests their feed page, the system generates the feed by inner joining event_log with friends. The result is then cached and set to timeout after 5 minutes. Scaling is achieved by varying this timeout. Hypothesised method: A task runs in the background and for each new, unprocessed item in event_log, it creates entries in the database table user_feed pairing that event with all of the users who are friends with the user who initiated the event. One table row pairs one event with one user. The problems with the standard method are well known – what if a lot of people's caches expire at the same time? The solution also does not scale well – the brief is for feeds to update as close to real-time as possible The hypothesised solution in my eyes seems much better; all processing is done offline so no user waits for a page to generate and there are no joins so database tables can be sharded across physical machines. However, if a user has 100,000 friends and creates 20 events in one session, then that results in inserting 2,000,000 rows into the database. Question: The question boils down to two points: Is this worst-case scenario mentioned above problematic, i.e. does table size have an impact on MySQL performance and are there any issues with this mass inserting of data for each event? Is there anything else I have missed?

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• How do I update a NSTableView when its data source has changed?

  - by Jergason

  I am working along with Cocoa Programming For Mac OS X (a great book). One of the exercises the book gives is to build a simple to-do program. The UI has a table view, a text field to type in a new item and an "Add" button to add the new item to the table. On the back end I have a controller that is the data source and delegate for my NSTableView. The controller also implements an IBAction method called by the "Add" button. It contains a NSMutableArray to hold the to do list items. When the button is clicked, the action method fires correctly and the new string gets added to the mutable array. However, my data source methods are not being called correctly. Here they be: - (NSInteger)numberOfRowsInTableView:(NSTableView *)aTableView { NSLog(@"Calling numberOfRowsInTableView: %d", [todoList count]); return [todoList count]; } - (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex { NSLog(@"Returning %@ to be displayed", [todoList objectAtIndex:rowIndex]); return [todoList objectAtIndex:rowIndex]; } Here is the rub. -numberOfRowsInTableView only gets called when the app first starts, not every time I add something new to the array. -objectValueForTableColumn never gets called at all. I assume this is because Cocoa is smart enough to not call this method when there is nothing to draw. Is there some method I need to call to let the table view know that its data source has changed, and it should redraw itself?

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• c++ Design pattern for CoW, inherited classes, and variable shared data?

  - by krunk

  I've designed a copy-on-write base class. The class holds the default set of data needed by all children in a shared data model/CoW model. The derived classes also have data that only pertains to them, but should be CoW between other instances of that derived class. I'm looking for a clean way to implement this. If I had a base class FooInterface with shared data FooDataPrivate and a derived object FooDerived. I could create a FooDerivedDataPrivate. The underlying data structure would not effect the exposed getters/setters API, so it's not about how a user interfaces with the objects. I'm just wondering if this is a typical MO for such cases or if there's a better/cleaner way? What peeks my interest, is I see the potential of inheritance between the the private data classes. E.g. FooDerivedDataPrivate : public FooDataPrivate, but I'm not seeing a way to take advantage of that polymorphism in my derived classes. class FooDataPrivate { public: Ref ref; // atomic reference counting object int a; int b; int c; }; class FooInterface { public: // constructors and such // .... // methods are implemented to be copy on write. void setA(int val); void setB(int val); void setC(int val); // copy constructors, destructors, etc. all CoW friendly private: FooDataPrivate *data; }; class FooDerived : public FooInterface { public: FooDerived() : FooInterface() {} private: // need more shared data for FooDerived // this is the ???, how is this best done cleanly? };

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• How can I make NSUndoManager's undo/redo action names work properly?

  - by Gabe

  I'm learning Cocoa, and I've gotten undo to work without much trouble. But the setActionName: method is puzzling me. Here's a simple example: a toy app whose windows contain a single text label and two buttons. Press the On button and the label reads 'On'. Press the Off button and the label changes to read 'Off'. Here are the two relevant methods (the only code I wrote for the app): -(IBAction) turnOnLabel:(id)sender { [[self undoManager] registerUndoWithTarget:self selector:@selector(turnOffLabel:) object:self]; [[self undoManager] setActionName:@"Turn On Label"]; [theLabel setStringValue:@"On"]; } -(IBAction) turnOffLabel:(id)sender { [[self undoManager] registerUndoWithTarget:self selector:@selector(turnOnLabel:) object:self]; [[self undoManager] setActionName:@"Turn Off Label"]; [theLabel setStringValue:@"Off"]; } Here's what I expect: I click the On button The label changes to say 'On' In the Edit menu is the item 'Undo Turn On Label' I click that menu item The label changes to say 'Off' In the Edit menu is the item 'Redo Turn On Label' In fact, all these things work as I expect apart from the last one. The item in the Edit menu reads 'Redo Turn Off Label', not 'Redo Turn On Label'. (When I click that menu item, the label does turn to On, as I'd expect, but this makes the menu item's name even more of a mystery. What am i misunderstanding, and how can I get these menu items to display the way I want them to?

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• Iframe/Popup redirecting opener window

  - by Bara

  Hello all, I have a page located at x.com. On this page is a button that, when clicked, will launch a new window (using javascript's window.open() method) to a page that is located at z.com. The popup does a few things, then redirects the original window (the opener, x.com) to a different page based on some parameters defined in the popup. This works fine in Firefox/Chrome, but not in IE. In IE (8 specifically, but I believe 7 also has this problem) the original window (the opener) is not redirected. Instead, a new window comes up and THAT window is redirected. I've tried many different methods to try and get this to work, including changing the popup to an iframe loaded on the page and having a function on the opener that the popup/iframe call. The problem seems to be that IE refuses to allow cross-domain sites to talk to each other via javascript. Is there a way around this? How can I get the parent window to redirect to a page based on parameters in a popup or iframe? Bara

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• (nested) user controls within a mvp pattern causing sporadic problems

  - by LLEA

  hi everyone, I have a serious problem with nested user controls (UCs) in WinForms while trying to implement the mvp pattern (passive view). The project consists of one model (designed as a singleton) and a set of different presenters with corresponding view interfaces. To avoid one huge view interface and therefore an overloaded main UI, I decided to make use of a set of different UCs. Each UC has one view interface and one presenter that can access the model. But there are nested UCs: meaning that one specialised UC implements sort of a basic UC. The main UI just represents a container for all those UCs. So far, so good (if not, please ask)?! There are two problems that I am facing now (but I guess both are of the same origin): From time to time it is not possible anymore to load the UCs and test them within the Visual Studio 2008 User Control Test Container. The error message just says that a project with an output type of class library cannot be started directly etc. I can "handle" that by unloading all UC projects and reloading them afterwards. (I guess the references to all mvp components and other UCs are then updated). Assuming that the implementation of my mvp pattern is okay and all those UCs are testable within the VS Test Container at a certain time - there is the biggest problem still left: I am not able to add any UC (even the basic and unnested ones) to a simple Form (UI). The error message: error message.jpg Could it be that my basic UC causes all these Problems?! It consists of two simple ComboBoxes and implements a basic presenter and basic view interface. Whenever I add this UC to a different UC the VS designer adds two references to the public getter methods of the UC as resources. I then manually remove those resources from the resx-file and commend the corresponding lines in the designer file. thx in advance

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