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  • TreeView Control Problem

    - by ProgNet
    Hi all, I have a public folder on the server that contains recursively nested sub folders. In the various Leaf folders contains Images. I wanted to create a server side file browser that will display the Images to the user. I am using the ASP.NET TreeView Control. I create the tree nodes using PopulateOnDemand. If the user click on a leaf directory I want the images in that folder to be displayed in a DataList Control. The problem is that when I click on a sub tree node (after I expanded it parent node) All the expanded sub tree disappears and only the parent node is showed with no + sign next to it !! ( I have set the TreeView's PopulateNodesFromClient property to true ) Can someone tell me what is the problem ?? Thanks Here is the code : <asp:TreeView ID="TreeView1" runat="server" AutoGenerateDataBindings="False" onselectednodechanged="TreeView1_SelectedNodeChanged" ontreenodepopulate="TreeView1_TreeNodePopulate"> </asp:TreeView> protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { string path = Server.MapPath("."); PopulateTopNodes(path); } } private void PopulateTopNodes(string pathToRootFolder) { DirectoryInfo dirInfo = new DirectoryInfo(pathToRootFolder); DirectoryInfo[] dirs = dirInfo.GetDirectories(); foreach (DirectoryInfo dir in dirs) { TreeNode folderNode = new TreeNode(dir.Name,dir.FullName); if (dir.GetDirectories().Length > 0) { folderNode.PopulateOnDemand = true; folderNode.Collapse(); } TreeView1.Nodes.Add(folderNode); } } protected void TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e) { if (IsCallback == true) { if (e.Node.ChildNodes.Count == 0) { LoadChildNode(e.Node); } } } private void LoadChildNode(TreeNode treeNode) { DirectoryInfo dirInfo = new DirectoryInfo(treeNode.Value); DirectoryInfo[] dirs = dirInfo.GetDirectories(); foreach (DirectoryInfo dir in dirs) { TreeNode folderNode = new TreeNode(dir.Name, dir.FullName); if(dir.GetDirectories().Length>0){ folderNode.PopulateOnDemand = true; folderNode.Collapse(); } treeNode.ChildNodes.Add(folderNode); } } protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e) { // Retrieve the images here }

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  • Page_Load or Page_Init

    - by balexandre
    Let's take a really simple example on using jQuery to ajaxify our page... $.load("getOrders.aspx", {limit: 25}, function(data) { // info as JSON is available in the data variable }); and in the ASP.NET (HTML part) page (only one line) <%@ Page Language="C#" AutoEventWireup="true" CodeFile="getOrders.aspx.cs" Inherits="getOrders" %> and in the ASP.NET (Code Behind) page public partial class getOrders : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string lmt = Request["limit"]; List<Orders> ords = dll.GetOrders(limit); WriteOutput( Newtonsoft.Json.JsonConvert.SerializeObject(ords) ); } private void WriteOutput(string s) { Response.Clear(); Response.Write(s); Response.Flush(); Response.End(); } } my question is Should it be protected void Page_Load(object sender, EventArgs e) or protected void Page_Init(object sender, EventArgs e) So we can save some milliseconds as we don't actually need to process the events for the page, or will Page_Init lack of some sorting of a method by the time it is called? P.S. Currently works fine in both methods, but I just want to understand the ins and outs of choosing one method over the other

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  • Printing the "source" class in a log statement with a log4j wrapper

    - by Dur4ndal
    My application has a homebrew logging class that I'm migrating to using log4j under the covers. However, since I'm using the homebrew class to pass the rest of the application's logging statements to log4j, the output statements are logged as coming from the wrapper class instead of the source class. Is there a way to ensure that the "correct" source is being shown besides creating new org.apache.log4j.Logger instances for every log statement? I've also tried using the Logger.log(String callerFQCN, Priority level, Object message, Throwable t) method, but it doesnt seem to be working, for example: public class Logger2 { public static org.apache.log4j.Logger log4JLogger = org.apache.log4j.Logger.getLogger(Logger2.class); public static void warning(Object source, String message) { log(source, message, Level.WARN, null) } private static void log(Object source, String message, Level level, Throwable t) { String className = source.getClass().getName(); System.out.println("Logging class should be " + className); log4JLogger.log(className, loggingLevel, message, t); } } When called by: public void testWarning() { Logger2.warning(new Integer(3), "This should warn"); } Prints: Logging class should be java.lang.Integer 2010-05-25 10:49:57,152 WARN test.Logger2 - This should warn

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  • Does ReleaseStringUTF do more than free memory?

    - by Bayou Bob
    Consider the following C code segments. Segment 1: char * getSomeString(JNIEnv *env, jstring jstr) { char * retString; retString = (*env)->GetStringUTFChars(env, jstr, NULL); return retString; } void useSomeString(JNIEnv *env, jobject jobj, char *mName) { jclass cl = (*env)->GetObjectClass(env, jobj); jmethodId mId = (*env)->GetMethodID(env, cl, mName, "()Ljava/lang/String;"); jstring jstr = (*env)->CallObjectMethod(env, obj, id, NULL); char * myString = getSomeString(env, jstr); /* ... use myString without modifing it */ free(myString); } Because myString is freed in useSomeString, I do not think I am creating a memory leak; however, I am not sure. The JNI spec specifically requires the use of ReleaseStringUTFChars. Since I am getting a C style 'char *' pointer from GetStringUTFChars, I believe the memory reference exists on the C stack and not in the JAVA heap so it is not in danger of being Garbage Collected; however, I am not sure. I know that changing getSomeString as follows would be safer (and probably preferable). Segment 2: char * getSomeString(JNIEnv *env, jstring jstr) { char * retString; char * intermedString; intermedString = (*env)->GetStringUTFChars(env, jstr, NULL); retString = strdup(intermedString); (*env)->ReleaseStringUTFChars(env, jstr, intermedString); return retString; } Because of our 'process' I need to build an argument on why getSomeString in Segment 2 is preferable to Segment 1. Is anyone aware of any documentation or references which detail the behavior of GetStringUTFChars and ReleaseStringUTFChars in relation to where memory is allocated or what (if any) additional bookkeeping is done (i.e. local Reference Pointer to the Java Heap being created, etc). What are the specific consequences of ignoring that bookkeeping. Thanks in advance.

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  • Playing FLV unexpectedly stops, but why?

    - by Josamoto
    I am trying to play an FLV video that is about 90Mb big, using the following snippet: private function playVideo(url:String):void { var customClient:Object = new Object(); customClient.onMetaData = metaDataHandler; var nc:NetConnection = new NetConnection(); nc.connect(null); var ns:NetStream = new NetStream(nc); ns.client = customClient; ns.play(url); var myVideo:Video = new Video(); myVideo.attachNetStream(ns); addChild(myVideo); function metaDataHandler(infoObject:Object):void { myVideo.width = 640; myVideo.x = stage.stageWidth / 2 - 640 / 2; myVideo.height = 400; myVideo.y = 230; } } The video is not going to be streamed across the internet, in fact, the application will run locally and videos will also be loaded locally from disc. When starting my application, the video starts, but at random locations, playback completely freezes up, without any errors being thrown at all. Does anybody have any idea as to why this might happen?

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  • C++ Conceptual problem with (Pointer) Pointers

    - by Ptr
    I have a structure usually containing a pointer to an int. However, in some special cases, it is necessary that this int pointer points to another pointer which then points to an int. Wow: I mentioned the word pointer 5 times so far! Is this even possible? I thought about it that way: Instead of using a second int pointer, which is most likely not possible as my main int pointer can only point to an int and not to another int pointer, I could make it a reference like this: int intA = 1; int intB = 2; int& intC = intB; int* myPointers[ 123 ]; myPointers[ 0 ] = &intA; myPointers[ 1 ] = &intB; myPointers[ 3 ] = &intC; So the above would do what I want: The reference to intB (intC) behaves quite like I want it to (If it gets changed it also changes intB) The problem: I can't change references once they are set, right? Or is there a way? Everything in short: How do I get a value to work with * (pointers) and ** (pointers to pointers)?

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  • please help me for performing serch in my program

    - by Abid
    i want to perform searching in my programe.. i have my class in which i have made a function i.e. public DataTable Search() { string SQL = "Select * from Customer where " + mField + " like '%" + mValue + "%'"; DataTable dt = new DataTable(); dt = dm.GetData(SQL); return (dt); } in which i have made setters and getters for mField and mValue.. where dm is the object of class Datamanagement in which i have made a function GetData i.e. public DataTable GetData(string SQL) { SqlCommand command = new SqlCommand(); SqlDataAdapter dbAdapter = new SqlDataAdapter(); DataTable DataTable = new DataTable(); command.Connection = clsConnection.GetConnection(); command.CommandText = SQL; dbAdapter.SelectCommand = command; dbAdapter.Fill(DataTable); return (DataTable); } and behind the search button, i have written.. private void btnfind_Click(object sender, EventArgs e) { //cust is the object of class customer// if (tbCustName.Text != "") { cust.Field="CustName"; cust.Value = tbCustName.Text; } else if (tbAddress.Text != "") { cust.Value = tbAddress.Text; cust.Field="Address"; } else if (tbEmail.Text != "") { cust.Value = tbEmail.Text; cust.Field="Email"; } else if (tbCell.Text != "") { cust.Value = tbCell.Text; cust.Field = "Cell"; } DataTable dt = new DataTable(); dt = cust.Search(); dgCustomer.DataSource = dt; RefreshGrid(); } where my referesh grid fuction does that : private void RefreshGrid() { DataTable dt = new DataTable(); dt = cust.GetCustomers(); dgCustomer.DataSource = dt; } but this is not working.. i dont knw y.. please help..

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  • Error In VB.Net code

    - by Michael
    I am getting the error "Format Exception was unhandled at "Do While objectReader.Peek < -1 " and after. any help would be wonderful. 'Date: Class 03/20/2010 'Program Purpose: When code is executed data will be pulled from a text file 'that contains the named storms to find the average number of storms during the time 'period chosen by the user and to find the most active year. between the range of 'years 1990 and 2008 Option Strict On Public Class frmHurricane Private _intNumberOfHuricanes As Integer = 5 Public Shared _intSizeOfArray As Integer = 7 Public Shared _strHuricaneList(_intSizeOfArray) As String Private _strID(_intSizeOfArray) As String Private _decYears(_intSizeOfArray) As Decimal Private _decFinal(_intSizeOfArray) As Decimal Private _intNumber(_intSizeOfArray) As Integer Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 'The frmHurricane load event reads the Hurricane text file and 'fill the combotBox object with the data. 'Initialize an instance of the StreamReader Object and declare variable page 675 on the book Dim objectReader As IO.StreamReader Dim strLocationAndNameOfFile As String = "C:\huricanes.txt" Dim intCount As Integer = 0 Dim intFill As Integer Dim strFileError As String = "The file is not available. Please restart application when available" 'This is where we code the file if it exist. If IO.File.Exists(strLocationAndNameOfFile) Then objectReader = IO.File.OpenText(strLocationAndNameOfFile) 'Read the file line by line until the file is complete Do While objectReader.Peek <> -1 **_strHuricaneList(intCount) = objectReader.ReadLine() _strID(intCount) = objectReader.ReadLine() _decYears(intCount) = Convert.ToDecimal(objectReader.ReadLine()) _intNumber(intCount) = Convert.ToInt32(objectReader.ReadLine()) intCount += 1** Loop objectReader.Close() 'With any luck the data will go to the Data Box For intFill = 0 To (_strID.Length - 1) Me.cboByYear.Items.Add(_strID(intFill)) Next Else MsgBox(strFileError, , "Error") Me.Close() End If End Sub

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  • Is this a good way to generically deserialize objects?

    - by Damien Wildfire
    I have a stream onto which serialized objects representing messages are dumped periodically. The objects are one of a very limited number of types, and other than the actual sequence of bytes that arrives, I have no way of knowing what type of message it is. I would like to simply try to deserialize it as an object of a particular type, and if an exception is thrown, try again with the next type. I have an interface that looks like this: public interface IMessageHandler<T> where T : class, IMessage { T Handle(string message); } // elsewhere: // (These are all xsd.exe-generated classes from an XML schema.) public class AppleMessage : IMessage { ... } public class BananaMessage : IMessage { ... } public class CoconutMessage : IMessage { ... } Then I wrote a GenericHandler<T> that looks like this: public class GenericHandler<T> : IMessageHandler<T> where T: class, IMessage { public class MessageHandler : IMessageHandler { T IMessageHandler.Handle(string message) { T result = default(T); try { // This utility method tries to deserialize the object with an // XmlSerializer as if it were an object of type T. result = Utils.SerializationHelper.Deserialize<T>(message); } catch (InvalidCastException e) { result = default(T); } return result; } } } Two questions: Using my GenericHandler<T> (or something similar to it), I'd now like to populate a collection with handlers that each handle a different type. Then I want to invoke each handler's Handle method on a particular message to see if it can be deserialized. If I get a null result, move onto the next handler; otherwise, the message has been deserialized. Can this be done? Is there a better way to deserialize data of unknown (but restricted) type?

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  • mvc design in a card game

    - by Hong
    I'm trying to make a card game. some classes I have are: CardModel, CardView; DeckModel, DeckView. The deck model has a list of card model, According to MVC, if I want to send a card to a deck, I can add the card model to the deck model, and the card view will be added to the deck view by a event handler. So I have a addCard(CardModel m) in the DeckModel class, but if I want to send a event to add the card view of that model to the deck view, I only know let the model has a reference to view. So the question is: If the card model and deck model have to have a reference to their view classes to do it? If not, how to do it better? Update, the code: public class DeckModel { private ArrayList<CardModel> cards; private ArrayList<EventHandler> actionEventHandlerList; public void addCard(CardModel card){ cards.add(card); //processEvent(event x); //must I pass a event that contain card view here? } CardModel getCards(int index){ return cards.get(index); } public synchronized void addEventHandler(EventHandler l){ if(actionEventHandlerList == null) actionEventHandlerList = new ArrayList<EventHandler>(); if(!actionEventHandlerList.contains(l)) actionEventHandlerList.add(l); } public synchronized void removeEventHandler(EventHandler l){ if(actionEventHandlerList!= null && actionEventHandlerList.contains(l)) actionEventHandlerList.remove(l); } private void processEvent(Event e){ ArrayList list; synchronized(this){ if(actionEventHandlerList!= null) list = (ArrayList)actionEventHandlerList.clone(); else return; } for(int i=0; i<actionEventHandlerList.size(); ++i){ actionEventHandlerList.get(i).handle(e); } } }

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  • Calling member functions dynamically

    - by user652511
    I'm pretty sure it's possible to call a class and its member function dynamically in Delphi, but I can't quite seem to make it work. What am I missing? // Here's a list of classes (some code removed for clarity) moClassList : TList; moClassList.Add( TClassA ); moClassList.Add( TClassB ); // Here is where I want to call an object's member function if the // object's class is in the list: for i := 0 to moClassList.Count - 1 do if oObject is TClass(moClassList[i]) then with oObject as TClass(moClassList[i]) do Foo(); I get an undeclared identifier for Foo() at compile. Clarification/Additional Information: What I'm trying to accomplish is to create a Change Notification system between business classes. Class A registers to be notified of changes in Class B, and the system stores a mapping of Class A - Class B. Then, when a Class B object changes, the system will call a A.Foo() to process the change. I'd like the notification system to not require any hard-coded classes if possible. There will always be a Foo() for any class that registers for notification. Maybe this can't be done or there's a completely different and better approach to my problem. By the way, this is not exactly an "Observer" design pattern because it's not dealing with objects in memory. Managing changes between related persistent data seems like a standard problem to be solved, but I've not found very much discussion about it. Again, any assistance would be greatly appreciated. Jeff

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  • how to pass arraylist as parameter to another screen

    - by user2867267
    how to pass arraylist as parameter to another activity in my condition im not using listview and checkif arraylist contain single element then pass that arrraylist as parameter toanother screen see thisline Category_name.get(position).toString()); how i remove position?? how to passs arraylist parameter toanother activity static ArrayList<Long> Menu_ID = new ArrayList<Long>(); static ArrayList<String> Category_name = new ArrayList<String>(); JSONArray school = json2.getJSONArray("data"); for (int i = 0; i < school.length(); i++) { JSONObject object = school.getJSONObject(i); Category_ID.add((long) i); Menu_ID.add(Long.parseLong(object.getString("menu_id"))); Category_name.add(object.getString("menu_title")); } Intent iMenuList = new Intent(MenuGroup.this, thirdstep.class); menuidvalue=""; menuidvalue =( Menu_ID.get(position)).toString(); iMenuList.putExtra("Menu_ID",menuidvalue); iMenuList.putExtra("menu_group", Category_name.get(position).toString()); startActivity(iMenuList);

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  • Does std::vector change its address? How to avoid

    - by kunigami
    Since vector elements are stored contiguously, I guess it may not have the same address after some push_back's , because the initial allocated space could not suffice. I'm working on a code where I need a reference to an element in a vector, like: int main(){ vector<int> v; v.push_back(1); int *ptr = &v[0]; for(int i=2; i<100; i++) v.push_back(i); cout << *ptr << endl; //? return 0; } But it's not necessarily true that ptr contains a reference to v[0], right? How would be a good way to guarantee it? My first idea would be to use a vector of pointers and dynamic allocation. I'm wondering if there's an easier way to do that? PS.: Actually I'm using a vector of a class instead of int, but I think the issues are the same.

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  • .NET remoting: System references wrong .NET dll, but how to cure ?

    - by Quandary
    Question: I defined an interface like below. The problem now is, that when I add the dll (API.dll) as reference in an asp.net project, it references a wrong API.dll, though I referenced the correct dll. In turn, it doesn't find GetLDAPlookup, but there is another method that is not in defined here, but in an older version of API.dll... I rebuilt the dll I referenced, so it is definitely the latest version that I added as reference. Do I have to add another GUID, or something ? Imports System.Runtime.InteropServices Namespace RemoteObject ''' <summary> ''' Defines server interface which will be deployed on every client ''' </summary> ''' <GuidAttribute("921DE547-32FA-40BB-961A-EA390B7AE27D")> _ Public Interface IServerMethods ''' <summary> ''' Function to call the server from the client ''' </summary> ''' <param name="strMessage">Some text</param> ''' Sub ServerPrint(ByVal strMessage As String) ''' <summary> ''' Function to call the server from the client ''' </summary> ''' <param name="strMessage">Some text</param> ''' <returns>Some interesting text</returns> ''' Function GetLDAPlookup(ByVal strMessage As String) As System.Data.DataSet End Interface End Namespace

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  • C++ reinterpret cast ?

    - by Ian
    I would like to cast one object of the class PointsList to another object Points3DList (and vice versa) where: template <class T> class PointsList { protected: std::vector <Point <T> *> points; //Only illustration, not possible with templaes }; and template <class T> class Points3DList { protected: std::vector <Point3D<T> *> points; //Only illustration, not possible with templaes }; Between Point and Point3D there is no relationship (inheritance nor composition)... template <class T> class Point { protected: T x; T y; }; template <class T> class Point3D { protected: T x; T y; T z; }; What do you think about conversion Points3DList <T> *pl3D = new Points3DList <T> (); ... PointsList <T> *pl = reinterpret_cast < PointList <T> * > ( pl3D ); where pl3D represents pointer to Points3DList object.. Can reinterpret_cast be used in this case or it is better to create a conversion function? Data model in this case can not be changed...

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  • IS operator behaving a bit strangely

    - by flockofcode
    1) According to my book, IS operator can check whether expression E (E is type) can be converted to the target type only if E is either a reference conversion, boxing or unboxing. Since in the following example IS doesn’t check for either of the three types of conversion, the code shouldn’t work, but it does: int i=100; if (i is long) //returns true, indicating that conversion is possible l = i; 2) a) B b; A a = new A(); if (a is B) b = (B)a; int i = b.l; class A { public int l = 100; } class B:A { } The above code always causes compile time error “Use of unassigned variable”. If condition a is B evaluates to false, then b won’t be assigned a value, but if condition is true, then it will. And thus by allowing such a code compiler would have no way of knowing whether the usage of b in code following the if statement is valid or not ( due to not knowing whether a is b evaluates to true or false) , but why should it know that? Intsead why couldn’t runtime handle this? b) But if instead we’re dealing with non reference types, then compiler doesn’t complain, even though the code is identical.Why? int i = 100; long l; if (i is long) l = i; thank you

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  • selected area to cut an image

    - by Oskar Marciniak
    Hi I would do the selected area to cut an image on picturebox control. I have the following code: using System; using System.Drawing; using System.Windows.Forms; namespace WindowsFormsApplication1 { public partial class Form1 : Form { private Rectangle rect; private Pen p; public Form1() { InitializeComponent(); } private void pictureBox1_Paint(object sender, PaintEventArgs e) { if (this.p == null) this.p = new Pen(Color.FromArgb(100, 200, 200, 200), 5); if (this.rect.Width > 0) e.Graphics.DrawRectangle(this.p, this.rect); } private void pictureBox1_MouseUp(object sender, MouseEventArgs e) { if (e.X < this.rect.X) { this.rect.Width = this.rect.X - e.X; this.rect.X = e.X; } else { this.rect.Width = e.X - this.rect.X; } if (e.Y < this.rect.Y) { this.rect.Height = this.rect.Y - e.Y; this.rect.Y = e.Y; } else { this.rect.Height = e.Y - this.rect.Y; } this.Invalidate(this.rect); } private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { this.rect.X = e.X; this.rect.Y = e.Y; } } } It returns an error here: Application.Run(new Form1()); Why? thanks for all replies ;p

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  • Embedded Youtube video in a Ruby on Rails page

    - by dan
    Hi, New to programming. I am trying to embed a YouTube video from a link stored in a database named "Promoter" into a ruby-on-rails page (.erb). I've looked at the source the code turns out, but the object video player does not appear (on heroku here: http://blazing-mountain-574.heroku.com/). The code in the home.html.erb file: <h1>Pages#home</h1> <p>Find me in app/views/pages/home.html.erb</p> <object width="640" height="385"> <param name="movie" value="<%= sanitize Promoter.first.link %>"> </param><param name="allowFullScreen" value="true"></param ><param name="allowscriptaccess" value="always"></param> <embed src="<%= sanitize Promoter.first.link %>" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="640" height="385"></embed></object> Is there something real simple that I'm missing?

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  • C++ privately contructed class

    - by Nona Urbiz
    How can I call a function and keep my constructor private? If I make the class static, I need to declare an object name which the compiler uses to call the constructor, which it cannot if the constructor is private (also the object would be extraneous). Here is the code I am attempting to use (it is not compilable): I want to keep the constructor private because I will later be doing a lot of checks before adding an object, modifying previous objects when all submitted variables are not unique rather than creating new objects. #include <iostream> #include <fstream> #include <regex> #include <string> #include <list> #include <map> using namespace std; using namespace tr1; class Referral { public: string url; map<string, int> keywords; static bool submit(string url, string keyword, int occurrences) { //if(Referrals.all.size == 0){ // Referral(url, keyword, occurrences); //} } private: list<string> urls; Referral(string url, string keyword, int occurrences) { url = url; keywords[keyword] = occurrences; Referrals.all.push_back(this); } }; struct All { list<Referral> all; }Referrals; int main() { Referral.submit("url", "keyword", 1); }

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  • Java getMethod with subclass parameter

    - by SelectricSimian
    I'm writing a library that uses reflection to find and call methods dynamically. Given just an object, a method name, and a parameter list, I need to call the given method as though the method call were explicitly written in the code. I've been using the following approach, which works in most cases: static void callMethod(Object receiver, String methodName, Object[] params) { Class<?>[] paramTypes = new Class<?>[params.length]; for (int i = 0; i < param.length; i++) { paramTypes[i] = params[i].getClass(); } receiver.getClass().getMethod(methodName, paramTypes).invoke(receiver, params); } However, when one of the parameters is a subclass of one of the supported types for the method, the reflection API throws a NoSuchMethodException. For example, if the receiver's class has testMethod(Foo) defined, the following fails: receiver.getClass().getMethod("testMethod", FooSubclass.class).invoke(receiver, new FooSubclass()); even though this works: receiver.testMethod(new FooSubclass()); How do I resolve this? If the method call is hard-coded there's no issue - the compiler just uses the overloading algorithm to pick the best applicable method to use. It doesn't work with reflection, though, which is what I need. Thanks in advance!

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  • Value types of variable size

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

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  • VB Change Calulator

    - by BlueBeast
    I am creating a VB 2008 change calculator as an assignment. The program is to use the amount paid - the amount due to calculate the total.(this is working fine). After that, it is to break that amount down into dollars, quarters, dimes, nickels, and pennies. The problem I am having is that sometimes the quantity of pennies, nickels or dimes will be a negative number. For example $2.99 = 3 Dollars and -1 Pennies. SOLVED Thanks to the responses, here is what I was able to make work with my limited knowledge. Option Explicit On Option Strict Off Option Infer Off Public Class frmMain Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click 'Clear boxes lblDollarsAmount.Text = String.Empty lblQuartersAmount.Text = String.Empty lblDimesAmount.Text = String.Empty lblNickelsAmount.Text = String.Empty lblPenniesAmount.Text = String.Empty txtOwed.Text = String.Empty txtPaid.Text = String.Empty lblAmountDue.Text = String.Empty txtOwed.Focus() End Sub Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click 'Close application' Me.Close() End Sub Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click ' Find Difference between Total Price and Total Received lblAmountDue.Text = Val(txtPaid.Text) - Val(txtOwed.Text) Dim intChangeAmount As Integer = lblAmountDue.Text * 100 'Declare Integers Dim intDollarsBack As Integer Dim intQuartersBack As Integer Dim intDimesBack As Integer Dim intNickelsBack As Integer Dim intPenniesBack As Integer ' Change Values Const intDollarValue As Integer = 100 Const intQuarterValue As Integer = 25 Const intDimeValue As Integer = 10 Const intNickelValue As Integer = 5 Const intPennyValue As Integer = 1 'Dollars intDollarsBack = CInt(Val(intChangeAmount \ intDollarValue)) intChangeAmount = intChangeAmount - Val(Val(intDollarsBack) * intDollarValue) lblDollarsAmount.Text = intDollarsBack.ToString 'Quarters intQuartersBack = CInt(Val(intChangeAmount \ intQuarterValue)) intChangeAmount = intChangeAmount - Val(Val(intQuartersBack) * intQuarterValue) lblQuartersAmount.Text = intQuartersBack.ToString 'Dimes intDimesBack = CInt(Val(intChangeAmount \ intDimeValue)) intChangeAmount = intChangeAmount - Val(Val(intDimesBack) * intDimeValue) lblDimesAmount.Text = intDimesBack.ToString 'Nickels intNickelsBack = CInt(Val(intChangeAmount \ intNickelValue)) intChangeAmount = intChangeAmount - Val(Val(intNickelsBack) * intNickelValue) lblNickelsAmount.Text = intNickelsBack.ToString 'Pennies intPenniesBack = CInt(Val(intChangeAmount \ intPennyValue)) intChangeAmount = intChangeAmount - Val(Val(intPenniesBack) * intPennyValue) lblPenniesAmount.Text = intPenniesBack.ToString End Sub End Class

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  • What type of objects can be sent back to an action Method using HTML.HIDDEN()

    - by Richard77
    Hello, 1)Let's say I've this form: <%Using(Html.BeginForm()){%> <% = Html.Hidden("myObject", (cast to the appropriate type)ViewData["KeyForMyObject"]%> <input type = "submit" "Submit Object"> <%}%> 2) Here's the Action which's supposed to intercept the value of the object public ActionResult MyAction(Type myObject) { //Do Something with the object } Here's my question: What type of objects the Hidden field can support? In fact, when ViewData["KeyForMyObject"] contains a string, int, or bool, myAction is able to retrieve the value. But, when it comes to objects, such as List, and dictionary, nothing happens. When I debug to check the local values, I see null for Type myObject in the MyMethod. So what are the rules in MVC when it comes to a List or Dictionary? ================================= EDIT To make things simpler, can I write something like this <% = Html.Hidden("contactDic", (Dictionary<string, string>) ViewData["contacts"])%> and expect to retrieve the dictionary in the action Method like this public ActionResult myMethod(Dictionary<string, string> contactDic) { //Do something with the dictionary } Thanks for Helping

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  • Audit many-to-many relationship in NHibernate

    - by Kendrick
    I have implemented listeners to audit changes to tables in my application using IPreUpdateEventListener and IPreInsertEventListener and everything works except for my many-to-many relationships that don't have additional data in the joining table (i.e. I don't have a POCO for the joining table). Each auditable object implements an IAuditable interface, so the event listener checks to see if a POCO is of type IAuditable, and if it is it records any changes to the object. Look up tables implement an IAuditableProperty inteface, so if a property of the IAuditable POCO is pointing to a lookup table, the changes are recorded in the log for the main POCO. So, the question is, how should I determine I'm working with a many-to-many collection and record the changes in my audit table? //first two checks for LastUpdated and LastUpdatedBy ommitted for brevity else if (newState[i] is IAuditable) { //Do nothing, these will record themselves separately } else if (!(newState[i] is IAuditableProperty) && (newState[i] is IList<object> || newState[i] is ISet)) { //Do nothing, this is a collection and individual items will update themselves if they are auditable //I believe this is where my many-to-many values are being lost } else if (!isUpdateEvent || !Equals(oldState[i], newState[i]))//Record only modified fields when updating { changes.Append(preDatabaseEvent.Persister.PropertyNames[i]) .Append(": "); if (newState[i] is IAuditableProperty) { //Record changes to values in lookup tables if (isUpdateEvent) { changes.Append(((IAuditableProperty)oldState[i]).AuditPropertyValue) .Append(" => "); } changes.Append(((IAuditableProperty)newState[i]).AuditPropertyValue); } else { //Record changes for primitive values if(isUpdateEvent) { changes.Append(oldState[i]) .Append(" => "); } changes.Append(newState[i]); } changes.AppendLine(); }

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  • NHibernate Performance Optimization | Suggestions invited!!!

    - by user336749
    Hi, I’m facing an issue with NHibernate performance and can you please suggest me some optimizations? Below mentioned is a small summary of my application architecture I have a windows service which is listening to a messaging bus. On receiving a message the service creates an object out of which a property is the received xml snippet and saves the message to the DB (uses NH). There is a WPF UI with a readonly connection to the DB, and on refresh of the UI it displays the objects on the screen. While the UI does a refresh, it retrieves the xml and deserializes it , from which the object’s properties are derived and binded to the screen. For example assume an xml XXX is received by the service, it deserializes the xml , creates the book object and save it to the DB and a property/column is SCHEMA which contains the xml snippet. The UI while refreshed searches all book objects by ID and creates the book objects out of the xml which is being saved (yes, the xml is the constructor param). Now my issue is that the refresh takes more than 2 minutes to display say 50 book objects. I analyzed it using the NHibernate profiler, and found that the time spend within the DB is negligible, however time spent to create the entities is proportionally huge(10ms:1990 ms).I guess it’s due to the fairly huge size of xml snippet and it’s deserialization. My question is, how can I improve the performance. I dispose sessions after every refresh and is not lazy loading (please note that the time spend in DB is negligible). On every refresh it’s possible that all objects are updated by some downstream systems or maybe one of them are updated.Can I implement some sort of caching mechanism in this case? Thanks in advance for any suggestions. Regards, -Mike

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