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  • List<string> doesn't update the UI when change occurs [WPF]

    - by Hard Turner
    <ListBox x:Name="MainList" HorizontalAlignment="Left" Height="468" Margin="10,10,0,0" VerticalAlignment="Top" Width="100" ItemsSource="{Binding Items,Mode=TwoWay}" DisplayMemberPath="Name"/> [Serializable()] public class MYcontainer : INotifyPropertyChanged,ISerializable { private List<MYClass> _items = new List<MYClass>(); public List<MYClass> Items { get{ return _items;} set { this._items =value; OnPropertyChanged("Items"); } public event PropertyChangedEventHandler PropertyChanged; public void OnPropertyChanged(string propertyName = null) { var eventHandler = this.PropertyChanged; if (eventHandler != null) eventHandler(this, new PropertyChangedEventArgs(propertyName)); } } when i add an item to "Items" the UI doesnt update, the binding is working fine, since if i closed the window and opened it again, the new items appear correctly what am i doing wrong? i know if i used observablecollection it will work fine, but shouldn't it work with List<? , i already have in another window a string[] property and it update fine

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  • JPA2 + Hibernate + Order By

    - by Jan
    Hi. Is it possible (using Hibernate and JPA2 Criteria Builder [1]) to order by a method's result rather than an entity's member? public class X { protected X() {} public String member; public String getEvaluatedValue() { // order by return "some text " + member; } } What I want to achive is order by the result of getEvaluatedValue(). Is that possible? Thanks in advanced. [1] http://docs.jboss.org/hibernate/entitymanager/3.5/reference/en/html_single/#querycriteria

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  • What is the explanation of this results in Java ?

    - by M.H
    I have the following code : public class Main { private int i = j; //1 private int j = 10; public static void main(String[] args) { System.out.println((new Main()).i); } } and there is a compiler error in line 1 because an illegal forward reference. But when I am trying the following code : public class Main { int i = getJ(); //1 int getJ(){ return j; } int j=10; public static void main(String[] args) { System.out.println(new Main().i); } } it works fine and the result is 0.Why there is no illegal forward reference in line 1 here?.The two codes look similar to me.

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  • Best ways to write a method that updates two objects in a multithreaded java environment?

    - by DanielHonig
    Suppose we have a class called AccountService that manages the state of accounts. AccountService is defined as interface AccountService{ public void debit(account); public void credit(account); public void transfer(Account account, Account account1); } Given this definition, what is the best way to implement transfer() so that you can guarantee that transfer is an atomic operation. I'm interested in answers that reference Java 1.4 code as well as answers that might use resources from java.util.concurrent in Java 5

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  • Java homework help, Error <identifier> expected

    - by user2900126
    Help with java homework this is my assignment that I have, this assignment code I've tried. But when I try to compile it I keep getting errors which I cant seem to find soloutions too: Error says <identifier> expected for Line 67 public static void () Assignment brief To write a simple java classMobile that models a mobile phone. Details the information stored about each mobile phone will include • Its type e.g. “Sony ericsson x90” or “Samsung Galaxy S”; • Its screen size in inches; You may assume that this a whole number from the scale 3 to 5 inclusive. • Its memory card capacity in gigabytes You may assume that this a whole number • The name of its present service provider You may assume this is a single line of text. • The type of contract with service provider You may assume this is a single line of text. • Its camera resolution in megapixels; You should not assume that this a whole number; • The percentage of charge left on the phone e.g. a fully charged phone will have a charge of 100. You may assume that this a whole number • Whether the phone has GPS or not. Your class will have fields corresponding to these attributes . Start by opening BlueJ, creating a new project called myMobile which has a classMobile and set up the fields that you need, Next you will need to write a Constructor for the class. Assume that each phone is manufactured by creating an object and specifying its type, its screen size, its memory card capacity, its camera resolution and whether it has GPS or not. Therefore you will need a constructor that allows you to pass arguments to initialise these five attributes. Other fields should be set to appropriate default values. You may assume that a new phone comes fully charged. When the phone is sold to its owner, you will need to set the service provider and type of contract with that provider so you will need mutator methods • setProvider () - - to set service provider. • setContractType - - to set the type of contract These methods will be used when the phones provider is changed. You should also write a mutator method ChargeUp () which simulates fully charging the phone. To obtain information about your mobile object you should write • accessor methods corresponding to four of its fields: • getType () – which returns the type of mobile; • getProvider () – which returns the present service provider; • getContractType () – which returns its type of contract; • getCharge () – which returns its remaining charge. An accessor method to printDetails () to print, to the terminal window, a report about the phone e.g. This mobile phone is a sony Erricsson X90 with Service provider BigAl and type of contract PAYG. At present it has 30% of its battery charge remaining. Check that the new method works correctly by for example, • creating a Mobile object and setting its fields; • calling printDetails () and t=checking the report corresponds to the details you have just given the mobile; • changing the service provider and contract type by calling setprovider () and setContractType (); • calling printDetails () and checking the report now prints out the new details. Challenging excercises • write a mutator methodswitchedOnFor () =which simulates using the phone for a specified period. You may assume the phone loses 1% of its charge for each hour that it is switched on . • write an accessor method checkcharge () whichg checks the phone remaing charge. If this charge has a value less than 25%, then this method returns a string containg the message Be aware that you will soon need to re-charge your phone, otherwise it returns a string your phone charge is sufficient. • Write a method changeProvider () which simulates changing the provider (and presumably also the type of service contract). Finally you may add up to four additional fields, with appropriate methods, that might be required in a more detailed model. above is my assignment that I have, this assignment code I've tried. But when I try to oompile it I keep getting errors which I cant seem to find soloutions too: Error says <identifier> expected for Line 67 public static void () /** * to write a simple java class Mobile that models a mobile phone. * * @author (Lewis Burte-Clarke) * @version (14/10/13) */ public class Mobile { // type of phone private String phonetype; // size of screen in inches private int screensize; // menory card capacity private int memorycardcapacity; // name of present service provider private String serviceprovider; // type of contract with service provider private int typeofcontract; // camera resolution in megapixels private int cameraresolution; // the percentage of charge left on the phone private int checkcharge; // wether the phone has GPS or not private String GPS; // instance variables - replace the example below with your own private int x; // The constructor method public Mobile(String mobilephonetype, int mobilescreensize, int mobilememorycardcapacity,int mobilecameraresolution,String mobileGPS, String newserviceprovider) { this.phonetype = mobilephonetype; this.screensize = mobilescreensize; this.memorycardcapacity = mobilememorycardcapacity; this.cameraresolution = mobilecameraresolution; this.GPS = mobileGPS; // you do not use this ones during instantiation,you can remove them if you do not need or assign them some default values //this.serviceprovider = newserviceprovider; //this.typeofcontract = 12; //this.checkcharge = checkcharge; Mobile samsungPhone = new Mobile("Samsung", "1024", "2", "verizon", "8", "GPS"); 1024 = screensize; 2 = memorycardcapacity; 8 = resolution; GPS = gps; "verizon"=serviceprovider; //typeofcontract = 12; //checkcharge = checkcharge; } // A method to display the state of the object to the screen public void displayMobileDetails() { System.out.println("phonetype: " + phonetype); System.out.println("screensize: " + screensize); System.out.println("memorycardcapacity: " + memorycardcapacity); System.out.println("cameraresolution: " + cameraresolution); System.out.println("GPS: " + GPS); System.out.println("serviceprovider: " + serviceprovider); System.out.println("typeofcontract: " + typeofcontract); } /** * The mymobile class implements an application that * simply displays "new Mobile!" to the standard output. */ public class mymobile { public static void main(String[] args) { System.out.println("new Mobile!"); //Display the string. } } public static void buildPhones(){ Mobile Samsung = new Mobile("Samsung", "3.0", "4gb", "8mega pixels", "GPS"); Mobile Blackberry = new Mobile("Blackberry", "3.0", "4gb", "8mega pixels", "GPS"); Samsung.displayMobileDetails(); Blackberry.displayMobileDetails(); } public static void main(String[] args) { buildPhones(); } } any answers.replies and help would be greatly appreciated as I really lost!

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  • Eclipse Plugin: Enablement of an Action based on the current selection - before the

    - by Itay
    Here's my problem: I am using the org.eclipse.ui.popupMenus extension point for adding a sub-menu whose Action that is bounded to the following class: public class MyAction implements IObjectActionDelegate { private Logic logic = Logic.getInstance(); // Singleton public void setActivePart(IAction a, IWorkbenchPart targetPart) { // Nothing here } public void run(IAction a) { // Do something... } public void selectionChanged(IAction a, ISelection s) { a.setEnabled(logic.isEnabled(s)); } } This action is working correctly in most cases (including the call a.setEnabled() in selectionChanged()). My problem at the very first time my action is being invoked. The selectionChanged method is called only after the menu item has been displayed (and not when the user has made the selection) which means that the call to a.setEnabled() will have no affect. Any ideas on how to make my action receive selectionChanged() notifications even before the fist time it is being invoked?

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  • Exception throws: encapsulate them or not?

    - by Simon
    Hi there. Once I read an MSDN article that encouraged the following programming paradigm: public class MyClass { public void Method1() { NewCustomException(); } public void Method2() { NewCustomException(); } void NewCustomException() { throw new CustomException("Exception message"); } } Do you think this paradigm makes sense? Wouldn't it be enough to store the exception message in a static const field and then pass it to the exception's constructor, instead of encapsulating the whole exception throw?

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  • abstract class need acces to subclass atribute

    - by user1742980
    I have a problem with my code. public abstract class SimplePolygon implements Polygon { ... public String toString(){ String str = "Polygon: vertices ="; for(int i = 0;i<varray.length;i++){ str += " "; str += varray[i]; } return str; } } public class ArrayPolygon extends SimplePolygon { private Vertex2D[] varray; public ArrayPolygon(Vertex2D[] array){ varray = new Vertex2D[array.length]; if (array == null){} for(int i = 0;i<array.length;i++){ if (array[i] == null){} varray[i] = array[i]; } ... } Problem is, that i'm not allowed to add any atribute or method to abstract class SimplePolygon, so i'cant properly initialize varray. It could simply be solved with protected atrib in that class, but for some (stupid) reason i'cant do that. Has anybody an idea how to solve it without that? Thanks for all help.

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  • Play! 1.2.5 with mongodb | Model Validation not happening

    - by TGV
    I have a simple User model whose fields are annotated with play validation annotations and morphia annotations like below. import play.data.validation.*; import play.modules.morphia.Model; import com.google.code.morphia.annotations.*; @Entity public class User extends Model{ @Id @Indexed(name="USERID", unique=true) public ObjectId userId; @Required public String userName; @Email @Indexed(name="USEREMAIL", unique=true) @Required public String userEmail; } Now I have a service which has a CreateNewUser method responsible for persisting the data. I have used Morphia plugin for the dao support. But the problem is that User Document gets persisted in mongo-db even if userName or userEmail is NULL. Also @Email validation does not happen // Below code is in app/controllers/Application.java User a = new User(); a.userName = "user1"; // calling bean to create user, userService is in app/service/UserService userService.createNewUser(a); It does not work even after adding @valid and validation.hasErrors() check.Below code is in app/service/UserService public void createNewUser(@Valid User user) { if (Validation.hasErrors()) { System.out.println("has errors"); } else { // TODO Auto-generated method stub userDao.save(user); } }

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  • why am i getting a null pointer when converting string to int array?

    - by Sackling
    My main method: public static void main(String[] args) { Scanner input = new Scanner(System.in); String string1; string1 = input.next(); LargeInteger firstInt = new LargeInteger(string1); System.out.printf("First integer: %s \n", firstInt.display()); } LargeInteger class: public class LargeInteger { private int[] intArray; //convert the strings to array public LargeInteger(String s) { for (int i = 0; i < s.length(); i++) { intArray[i] = Character.digit(s.charAt(i), 10); // in base 10 } } //display the strings public String display() { String result = ""; for (int i = 0; i < intArray.length; i++) { result += intArray[i]; } return result.toString(); } }

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  • TFS2010 API - Which server event fires when checkin notes are changed?

    - by user3708981
    I've written a TFS plugin that impliments the ISubscribe interface, and creates an external ticket base off of the contents of a check-in note. What I would like to do, if when I go back through older TFS check-ins in VS and edit a check-in note, the plugin would process that event and create an external ticket retroactively. What event / SubscribedType do I need to subscribe to in order for ProcessEvents to fire? My stubbed out code - using Microsoft.TeamFoundation.Client; using Microsoft.TeamFoundation.Common; using Microsoft.TeamFoundation.VersionControl.Client; // From C:\Program Files\Microsoft Team Foundation Server 2010\Tools\ using Microsoft.TeamFoundation.Framework.Server; using Microsoft.TeamFoundation.VersionControl.Server; using Changeset = Microsoft.TeamFoundation.VersionControl.Server.Changeset; public class EmbeddedWorkItemEventHandler : ISubscriber { const string EVENT_NAME = "TicketEvent"; const string APP_LOG = "Application"; public Type[] SubscribedTypes() { return new Type[1] { typeof(CheckinNotification) }; // What else do I need here? } public string Name { get { return EVENT_NAME; } } public SubscriberPriority Priority { get { return SubscriberPriority.Normal; } } public EventNotificationStatus ProcessEvent(TeamFoundationRequestContext requestContext, NotificationType notificationType, object notificationEventArgs, out int statusCode, out string statusMessage, out ExceptionPropertyCollection properties) { // Create the event source, if it doesn't exist if (!System.Diagnostics.EventLog.SourceExists(EVENT_NAME)) { System.Diagnostics.EventLog.CreateEventSource(EVENT_NAME, APP_LOG); } statusCode = 0; properties = null; statusMessage = String.Empty; string ErrorLine = ""; try { // Here we'll validate the Ticket name if (notificationType == NotificationType.DecisionPoint && notificationEventArgs is CheckinNotification) { //Check-in blocking logic here. } else if (notificationType == NotificationType.Notification && notificationEventArgs is CheckinNotification) { // Tickets on check-in here. } } Catch { // Error checking } return EventNotificationStatus.ActionPermitted; }

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  • Binding Data Template element to property on sub-class

    - by TerrorAustralis
    Hi guys, I have a class, for experiment sake call it foo() and another class, call it bar() I have a data template for class foo() defined in my xaml, but one of foo()'s properties is a bar() object such that foo() { Public string Name {get; set;} Public int ID {get; set;} Public bar barProp {get; set;} } and bar() { Public string Description{get; set;} } I want my data template of foo to display the Description property of bar. I have tried the simple <textblock Text="{Binding Path=barProp.Description}" /> and variants to no avail Seeking wisdom, DJ

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  • Creating parameterized type object using annonymous class

    - by Andrei Fierbinteanu
    This might be a stupid question, but I just saw a question asking how to create a Type variable for a generic type. The consensus seemed to be that you should have a dummy method returning that type, and then use reflection to get it (in this case he wanted Map<String, String>). Something like this : public Map<String, String> dummy() { throw new Error(); } Type mapStringString = Class.forName("ThisClass").getMethod("dummy").getGenericReturnType(); My question is, not having used reflection that much, couldn't you just do something like: Type mapStringString = new ParameterizedType() { public Type getRawType() { return Map.class; } public Type getOwnerType() { return null; } public Type[] getActualTypeArguments() { return new Type[] { String.class, String.class }; } }; Would this work? If not, why not? And what are some of the dangers/problems if it does (besides being able to return some Type like Integer<String> which is obviously not possible.

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  • C++: inheritance problem

    - by Helltone
    It's quite hard to explain what I'm trying to do, I'll try: Imagine a base class A which contains some variables, and a set of classes deriving from A which all implement some method bool test() that operates on the variables inherited from A. class A { protected: int somevar; // ... }; class B : public A { public: bool test() { return (somevar == 42); } }; class C : public A { public: bool test() { return (somevar > 23); } }; // ... more classes deriving from A Now I have an instance of class A and I have set the value of somevar. int main(int, char* []) { A a; a.somevar = 42; Now, I need some kind of container that allows me to iterate over the elements i of this container, calling i::test() in the context of a... that is: std::vector<...> vec; // push B and C into vec, this is pseudo-code vec.push_back(&B); vec.push_back(&C); bool ret = true; for(i = vec.begin(); i != vec.end(); ++i) { // call B::test(), C::test(), setting *this to a ret &= ( a .* (&(*i)::test) )(); } return ret; } How can I do this? I've tried two methods: forcing a cast from B::* to A::*, adapting a pointer to call a method of a type on an object of a different type (works, but seems to be bad); using std::bind + the solution above, ugly hack; changing the signature of bool test() so that it takes an argument of type const A& instead of inheriting from A, I don't really like this solution because somevar must be public.

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  • AndEngine: Black screen when using LayoutGameActivity

    - by Lemuel Hogben
    I used to use SimpleBaseGameActivity for my app and everything was ok, but now I want to add some ads into the app, so I tried to use LayoutGameActivity. But I get the screen completely black and I don't know why. That's my code: public class AcGame extends LayoutGameActivity { [...] @Override protected int getLayoutID() { return R.layout.ad; } @Override protected int getRenderSurfaceViewID() { return R.id.layout_render; } @Override public EngineOptions onCreateEngineOptions() { [...] return new EngineOptions(true, ScreenOrientation.PORTRAIT_FIXED, resolution, camera); } @Override public void onCreateResources(OnCreateResourcesCallback pOnCreateResourcesCallback) throws Exception { createResources(); pOnCreateResourcesCallback.onCreateResourcesFinished(); } @Override public void onCreateScene(OnCreateSceneCallback pOnCreateSceneCallback) throws Exception { pOnCreateSceneCallback.onCreateSceneFinished(createScene()); } @Override public void onPopulateScene(Scene pScene, OnPopulateSceneCallback pOnPopulateSceneCallback) throws Exception { pOnPopulateSceneCallback.onPopulateSceneFinished(); } And that's my layout: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="top" android:id="@+id/layout_ad" > <Button android:layout_width="fill_parent" android:layout_height="fill_parent" android:text="Ad Sample"/> </LinearLayout> <org.andengine.opengl.view.RenderSurfaceView android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center" android:id="@+id/layout_render" /> </LinearLayout> When I'm trying to debug, I can see that EngineOptions are creating, but no one of the LayoutGameActivity's methods was called (onCreateResources, onCreateScene or onPopulateScene). Can someone tell me what I've missed?

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  • BadPaddingException in Android encrypt

    - by DarthRoman
    Hi everyone, I am making an Android application, and I want to encrypt a String before sending it to a DataBase, and encrytpion is correct. The problem is when I am going to decrypt the String, because I get a BadPaddingException and I have no idea where the problem is. Here is the code: public final static String HEX = "36A52C8FB7DF9A3F"; public static String encrypt(String seed, String cleartext) throws Exception { byte[] rawKey = getRawKey(seed.getBytes()); byte[] result = encrypt(rawKey, cleartext.getBytes()); return toHex(result); } public static String decrypt(String seed, String encrypted) throws Exception { byte[] rawKey = getRawKey(seed.getBytes()); byte[] enc = toByte(encrypted); byte[] result = decrypt(rawKey, enc); return new String(result); } public static String toHex(String txt) { return toHex(txt.getBytes()); } public static String fromHex(String hex) { return new String(toByte(hex)); } public static byte[] toByte(String hexString) { int len = hexString.length()/2; byte[] result = new byte[len]; for (int i = 0; i < len; i++) result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue(); return result; } public static String toHex(byte[] buf) { if (buf == null) return ""; StringBuffer result = new StringBuffer(2*buf.length); for (int i = 0; i < buf.length; i++) { appendHex(result, buf[i]); } return result.toString(); } private static byte[] getRawKey(byte[] seed) throws Exception { KeyGenerator kgen = KeyGenerator.getInstance("AES"); SecureRandom sr = SecureRandom.getInstance("SHA1PRNG"); sr.setSeed(seed); kgen.init(128, sr); // 192 and 256 bits may not be available SecretKey skey = kgen.generateKey(); byte[] raw = skey.getEncoded(); return raw; } private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.ENCRYPT_MODE, skeySpec); byte[] encrypted = cipher.doFinal(clear); return encrypted; } private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.DECRYPT_MODE, skeySpec); byte[] decrypted = cipher.doFinal(encrypted); return decrypted; } private static void appendHex(StringBuffer sb, byte b) { sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f)); } I encrypt and decrypt with this code: String encrypted = encrypt(HEX, "some text"); String decrypted = decrypt(HEX, encrypted); Can anyone help me please? Thank you very much!!

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  • PHP 5.3 and interface \ArrayAccess

    - by Jakub Lédl
    I'm now working on a project and I have one class that implements the ArrayAccess interface. Howewer, I'm getting an error that says that my implementation: must be compatible with that of ArrayAccess::offsetSet(). My implementation looks like this: public function offsetSet($offset, $value) { if (!is_string($offset)) { throw new \LogicException("..."); } $this->params[$offset] = $value; } So, to me it looks like my implementation is correct. Any idea what is wrong? Thanks very much! The class look like this: class HttpRequest implements \ArrayAccess { // tons of private variables, methods for working // with current http request etc. Really nothing that // could interfere with that interface. // ArrayAccess implementation public function offsetExists($offset) { return isset ($this->params[$offset]); } public function offsetGet($offset) { return isset ($this->params[$offset]) ? $this->params[$offset] : NULL; } public function offsetSet($offset, $value) { if (!is_string($offset)) { throw new \LogicException("You can only assing to params using specified key."); } $this->params[$offset] = $value; } public function offsetUnset($offset) { unset ($this->params[$offset]); } }

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  • How are ambigous methods resolved in java ?

    - by Jijoy
    Hi, I have a question. package org.study.algos; public class Study { public static void main(String[] args) { A a = new A(); a.m1(null); } } class A { public void m1(String s) { System.out.println("String"); System.out.println(s); } public void m1(Object obj) { System.out.println("Object"); System.out.println(obj); } } Here, the output is String null Why does the JVM resolve the method to one with a String argument? Thanks in advance J

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  • ASP.NET MVC and Paging - Search & Result Scenario

    - by devforall
    I have forms in my page a get and a post and i want add pager on my get form .. so i cant page through the results.. The problem that i am having is when i move to the second page it does not display anything.. I am using this library for paging .. http://stephenwalther.com/Blog/archive/2008/09/18/asp-net-mvc-tip-44-create-a-pager-html-helper.aspx this my actions code. [AcceptVerbs("GET")] public ActionResult SearchByAttraction() { return View(); } [AcceptVerbs("POST")] public ActionResult SearchByAttraction(int? id, FormCollection form) {.... } and this is what i am using on my get form to page through <%= Html.Pager(ViewData.Model)% //but when i do this it goes to this method [AcceptVerbs("GET")] public ActionResult SearchByAttraction() instead of going to this this [AcceptVerbs("POST")] public ActionResult SearchByAttraction(int? id, FormCollection form) which sort of makes sence .. but i cant really think of any other way of doing this Any help would be very appreciated.. Thanx

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  • How can I prevent a field from being copied to the client proxy in WCF RIA?

    - by Martin Doms
    Is there a metadata attribute I can use to prevent a field from being accessible on the client in a WCF RIA services? I sure I have seen this before, but I'm drawing a blank and Google isn't helping. It would look something like [MetadataType(typeof(User.UserMetadata))] public partial class User { internal sealed class UserMetadata { private UserMetadata() { } public int Id { get; set; } [HideFromClientProxy] public string PasswordSalt { get; set; } } }

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  • runtime/compile time polymorphism

    - by dmadhavaraj
    Hi , In the below code , why b1.subtract() fails . Please explain me the reason ie., what happens in JVM while invoking that method . class Base { public void add() { System.out.println("Base ADD"); } } class Child extends Base { public void add(){ System.out.println("Child ADD"); } public void subtract() { System.out.println("Child Subtract"); } } class MainClass { public static void main(String args[]) { Base b1 = new Base(); Base b2 = new Child(); Child b3 = new Child(); b1.add(); b1.subtract(); // ?????????** b2.add(); b3.subtract(); } }

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  • 'Scanner' does not name a type error in g++

    - by Max
    Hi. I'm trying to compile code in g++ and I get the following errors: In file included from scanner.hpp:8, from scanner.cpp:5: parser.hpp:14: error: ‘Scanner’ does not name a type parser.hpp:15: error: ‘Token’ does not name a type Here's my g++ command: g++ parser.cpp scanner.cpp -Wall Here's parser.hpp: #ifndef PARSER_HPP #define PARSER_HPP #include <string> #include <map> #include "scanner.hpp" using std::string; class Parser { // Member Variables private: Scanner lex; // Lexical analyzer Token look; // tracks the current lookahead token // Member Functions <some function declarations> }; #endif and here's scanner.hpp: #ifndef SCANNER_HPP #define SCANNER_HPP #include <iostream> #include <cctype> #include <string> #include <map> #include "parser.hpp" using std::string; using std::map; enum { // reserved words BOOL, ELSE, IF, TRUE, WHILE, DO, FALSE, INT, VOID, // punctuation and operators LPAREN, RPAREN, LBRACK, RBRACK, LBRACE, RBRACE, SEMI, COMMA, PLUS, MINUS, TIMES, DIV, MOD, AND, OR, NOT, IS, ADDR, EQ, NE, LT, GT, LE, GE, // symbolic constants NUM, ID, ENDFILE, ERROR }; class Token { public: int tag; int value; string lexeme; Token() {tag = 0;} Token(int t) {tag = t;} }; class Num : public Token { public: Num(int v) {tag = NUM; value = v;} }; class Word : public Token { public: Word() {tag = 0; lexeme = "default";} Word(int t, string l) {tag = t; lexeme = l;} }; class Scanner { private: int line; // which line the compiler is currently on int depth; // how deep in the parse tree the compiler is map<string,Word> words; // list of reserved words and used identifiers // Member Functions public: Scanner(); Token scan(); string printTag(int); friend class Parser; }; #endif anyone see the problem? I feel like I'm missing something incredibly obvious.

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  • Timer in java ,time difference problem

    - by javatechi
    I want to create a timer for my app. The sample code is shown below. When the method datetwo() is called the same time in milliseconds is shown as there in the main method. Please help me out with this import java.util.Date; import java.util.Timer; public class TimerChe { Timer timer; static Date date = new Date(); static Date date2 = new Date(); public static void timerMethod(){ new Thread() { public void run() { try { while (true) { sleep(10000); datetwo(); } } catch (InterruptedException ex) { } } }.start(); } public static void datetwo() { System.out.println ("OK, It's time to do something!") ; System.out.println("The Time is " + date2.getTime() + " milliseconds since 1970/01/01"); } public static void main(String args[]) throws Exception { System.out.println("The Time is " + date.getTime() + " milliseconds since 1970/01/01" ); System.out.println ("Schedule something to do in the mean time.") ; timerMethod(); } }

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  • Does the "using" directive provide any benefit?

    - by Adam Drummond
    Is there a programmatic benefit to using a using statement? Notice the difference between this sample: using Application.Data; namespace Application.Web { public class SampleClass { public void SampleMethod() { List<Category> categories = CreateCategoriesData(); Category expected = categories[0]; ... ... } } } And this one: namespace Application.Web { public class SampleClass { public void SampleMethod() { List<Data.Category> categories = CreateCategoriesData(); Data.Category expected = categories[0]; ... ... } } }

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