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• A Newbie question regarding Software Development

  - by Sharif

  Hi, I'm going to complete my B.pharm (Hons.) degree and, you know, I don't have much knowledge about programing. I was wondering to build a software on my own. Could you guys tell me what to learn first for that? Is it too hard for a student of other discipline to build a software? Let me know please. The software I want to make is like a dictionary (or more specifically like "Physician's Desk Reference"). It should find the generic name, company name, indication, price etc. of a drug when I enter the brand name and vice versa. To build a software like that what programing language could help me most and what (and how many) language should I learn first? In my country, there is no practice of Community pharmacy (most of the pharmacy stores are run by unskilled people), that's why this type of thing could help them sell drugs. Would you please tell me what I'm to do and how tough it is? I'm very keen to learn programming. Thanks in advance NB: I started this post in ASKREDDIT section but it seems that was not the right place for poll type question, so I post it again in this section

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• Silverlight: How can I built an overview display block for any XAML?

  - by Ryan Bates

  Hi all, I am trying to create a generic "overview" control for any XAML. A good example of the desired effect would be on Google Maps or Bing maps: The main map zooms into some content, while a small "overview" block is docked to one of the map corners, showing the user where he/she is zoomed into. My content is all placed inside a <Canvas>, which can then be scaled and zoomed with transforms. While the user does this kind of navigation, I would like to give them a visual indication of where they are in the larger context of the content. I have tried to take a 'screenshot' of the XAML before the user starts navigating, i.e. create a WriteableBitmap wbImageData = new WriteableBitmap(TheCanvas, null); and then displaying it in an Image. Based on the user's scrolling and zooming activity, a Rectangle displays which part of the content is currently visible in the display area. This works OK-ish (still clunky), but the image has to be redone everytime the content changes. Is there a simple way to create this kind of preview, or does anyone know of a component that does it? Thanks!

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• Hashing the state of a complex object in .NET

  - by Jan

  Some background information: I am working on a C#/WPF application, which basically is about creating, editing, saving and loading some data model. The data model contains of a hierarchy of various objects. There is a "root" object of class A, which has a list of objects of class B, which each has a list of objects of class C, etc. Around 30 classes involved in total. Now my problem is that I want to prompt the user with the usual "you have unsaved changes, save?" dialog, if he tries to exit the program. But how do I know if the data in current loaded model is actually changed? There is of course ways to solve this, like e.g. reloading the model from file and compare against the one in memory value by value or make every UI control set a flag indicating the model has been changed. Now instead, I want to create a hash value based on the model state on load and generate a new value when the user tries to exit, and compare those two. Now the question: So inspired of that, I was wondering if there exist some way to generate a hash value from the (value)state of some arbitrary complex object? Preferably in a generic way, e.g. no need to apply attributes to each involved class/field. One idea could be to use some of .NET's serialization functionality (assuming it will work out-of-the-box in this case) and apply a hash function to the content of the resulting file. However, I guess there exist some more suitable approach. Thanks in advance.

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• C# algorithm for figuring out different possible combinations...

  - by ttomsen

  I have 10 boxes, each box can hold one item from a group/type of items, each 'group' type only fits in one of the 10 box types. The pool can have n number of items. The groups have completely distinct items. Each item has a price, i want an algorithm that will generate all the different possibilities, so i can figure out different price points. so a smaller picture of the problem BOX A - can have item 1,2,3,4 in it BOX B - can have item 6,7,8,9,10,11,12 BOX C - can have item 13,15,16,20,21 The items are stored in a db, they have a column which denotes which box they can go in. All box types are stored in an array, and I can put the items in a generic list. Anyone see a straightforward way to do this. I have tried doing 10 nested foreach's to see if i could find a simpler way. The nested loops will take MANY hours to run. the nested for each's basically pull all combinations, then calculate a rank for each combination, and store the top 10 ranked combination of items for output

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• template specialization of a auto_ptr<T>

  - by Chris Kaminski

  Maybe I'm overcomplicating things, but then again, I do sort of like clean interfaces. Let's say I want a specialization of auto_ptr for an fstream - I want a default fstream for the generic case, but allow a replacement pointer? tempate <> class auto_ptr<fstream> static fstream myfStream; fstream* ptr; public: auto_ptr() { // set ptr to &myfStream; } reset(fstream* newPtr) { // free old ptr if not the static one. ptr = newPtr }; } Would you consider something different or more elegant? And how would you keep something like the above from propagating outside this particular compilation unit? [The actual template is a boost::scoped_ptr.] EDIT: It's a contrived example. Ignore the fstream - it's about providing a default instance of object for an auto_ptr. I may not want to provide a specialized instance, but would like to keep the auto_ptr semantics for this static default object. class UserClass { public: auto_ptr<fstream> ptr; UserClass() { } } I may not provide an dynamic object at construction time - I still want it to have a meaningful default. Since I'm not looking at ownership-transfer semantics, it really shouldn't matter that my pointer class is pointing to a statically allocated object, no?

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• Pass Linq Expression to a function

  - by Kushan Hasithe Fernando

  I want to pass a property list of a class to a function. with in the function based on property list I'm going to generate a query. As exactly same functionality in Linq Select method. Here I'm gonna implement this for Ingress Database. As an example, in front end I wanna run a select as this, My Entity Class is like this public class Customer { [System.Data.Linq.Mapping.ColumnAttribute(Name="Id",IsPrimaryKey=true)] public string Id { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Name")] public string Name { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Address")] public string Address { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Email")] public string Email { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Mobile")] public string Mobile { get; set; } } I wanna call a Select function like this, var result = dataAccessService.Select<Customer>(C=>C.Name,C.Address); then,using result I can get the Name and Address properties' values. I think my Select function should looks like this, ( *I think this should done using Linq Expression. But im not sure what are the input parameter and return type. * ) Class DataAccessService { // I'm not sure about this return type and input types, generic types. public TResult Select<TSource,TResult>(Expression<Func<TSource,TResult>> selector) { // Here using the property list, // I can get the ColumnAttribute name value and I can generate a select query. } } This is a attempt to create a functionality like in Linq. But im not an expert in Linq Expressions. There is a project call DbLinq from MIT, but its a big project and still i couldn't grab anything helpful from that. Can someone please help me to start this, or can someone link me some useful resources to read about this.

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• Accessing C# Variables in JavaScript

  - by mshahbazm

  I am Developing Windows 8 application in which i have to access variables of C# class in java script function, But Unfortunately i don not know how to do this: My C# class code is: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Pakistan_Tour { public class UniversalValues { public static double xC; public static double yC; public static int selectedcity; public int retcity() { return selectedcity; } public void setcity(int val) { selectedcity=val; } public void setxy(double x, double y) { xC = x; yC = y; } public double getx() { return xC; } public double gety() { return yC; } } } I have to access the value of variables: xC and yc in java script I am doing like: function initialize() { var x = "<%=xC%>"; var y = "<%=yC%>"; } but is not working, Kindly help me with this, Thanks in advance.

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• Trying to calculate large numbers in Python with gmpy. Python keeps crashing?

  - by Ryan Peschel

  I was recommended to use gmpy to assist with calculating large numbers efficiently. Before I was just using python and my script ran for a day or two and then ran out of memory (not sure how that happened because my program's memory usage should basically be constant throughout.. maybe a memory leak?) Anyways, I keep getting this weird error after running my program for a couple seconds: mp_allocate< 545275904->545275904 > Fatal Python error: mp_allocate failure This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Also, python crashes and Windows 7 gives me the generic python.exe has stopped working dialog. This wasn't happening with using standard python integers. Now that I switch to gmpy I am getting this error just seconds in to running my script. I thought gmpy was specialized in dealing with large number arithmetic? For reference, here is a sample program that produces the error: import gmpy2 p = gmpy2.xmpz(3000000000) s = gmpy2.xmpz(2) M = s**p for x in range(p): s = (s * s) % M I have 10 gigs of RAM and without gmpy this script ran for days without running out of memory (still not sure how that happened considering s never really gets larger.. Anyone have any ideas? EDIT: Forgot to mention I am using Python 3.2

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• What OOP pattern to use when only adding new methods, not data?

  - by Jonathon Reinhart

  Hello eveyone... In my app, I have deal with several different "parameters", which derive from IParameter interface, and also ParamBase abstract base class. I currently have two different parameter types, call them FooParameter and BarParameter, which both derive from ParamBase. Obviously, I can treat them both as IParameters when I need to deal with them generically, or detect their specific type when I need to handle their specific functionality. My question lies in specific FooParameters. I currently have a few specific ones with their own classes which derive from FooParameter, we'll call them FP12, FP13, FP14, etc. These all have certain characteristics, which make me treat them differently in the UI. (Most have names associated with the individual bits, or ranges of bits). Note that these specific, derived FP's have no additional data associated with them, only properties (which refer to the same data in different ways) or methods. Now, I'd like to keep all of these parameters in a Dictionary<String, IParameter> for easy generic access. The problem is, if I want to refer to a specific one with the special GUI functions, I can't write: FP12 fp12 = (FP12)paramList["FP12"] because you can't downcast to a derived type (rightfully so). But in my case, I didn't add any data, so the cast would theoretically work. What type of programming model should I be using instead? Thanks!

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• Rails: using find method to access joined tables for polymorphic relationships

  - by DJTripleThreat

  Ok, I have a generic TimeSlot model that deals with a start_at and an end_at for time spans. A couple models derive from this but I'm referring to one in this question: AppointmentBlock which is a collection of Appointments. I want to validate an AppointmentBlock such that no other AppointmentBlocks have been scheduled for a particular Employee in the same time frame. Since AppointmentBlock has a polymorphic association with TimeSlot, you have to access the AppointmentBlock's start_at and end_at through the TimeSlot like so: appt_block.time_slot.start_at This means that I need to have some kind of join in my :conditions for my find() method call. Here is my code so far: #inside my appointment_block.rb model validate :employee_not_double_booked def employee_not_double_booked unless self.employee_id # this find's condition is incorrect because I need to join time_slots to get access # to start_at and end_at. How can I do this? blocks = AppointmentBlock.find(:first, :conditions => ['employee_id = ? and (start_at between ? and ? or end_at between ? and ?)', self.employee_id, self.time_slot.start_at, self.time_slot.end_at, self.time_slot.start_at, self.time_slot.end_at]) # pseudo code: # collect a list of appointment blocks that end after this # apointment block starts or start before this appointment # block ends that are also associated with this appointment # blocks assigned employee # if the count is great then 0 the employee has been double # booked. # if a block was found that means this employee is getting # double booked so raise an error errors.add "AppointmentBlock", "has already been scheduled during this time" if blocks end end Since AppointmentBlock doesn't have a start_at or an end_at how can I join with the time_slots table to get those conditions to work?

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• Help a CRUD programmer think about an "approval workflow"

  - by gerdemb

  I've been working on a web application that is basically a CRUD application (Create, Read, Update, Delete). Recently, I've started working on what I'm calling an "approval workflow". Basically, a request is generated for a material and then sent for approval to a manager. Depending on what is requested, different people need to approve the request or perhaps send it back to the requester for modification. The approvers need to keep track of what to approve what has been approved and the requesters need to see the status of their requests. As a "CRUD" developer, I'm having a hard-time wrapping my head around how to design this. What database tables should I have? How do I keep track of the state of the request? How should I notify users of actions that have happened to their requests? Is their a design pattern that could help me with this? Should I be drawing state-machines in my code? I think this is a generic programing question, but if it makes any difference I'm using Django with MySQL.

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• opening a new page and passing a parameter to it with Javascript

  - by recipriversexclusion

  I have a JS function that processes XML I GET from a server to dynamically create a table as below // Generate table of services by parsing the returned XML service list. function convertServiceXmlDataToTable(xml) { var tbodyElem = document.getElementById("myTbody"); var trElem, tdElem; var j = 0; $(xml).find("Service").each(function() { trElem = tbodyElem.insertRow(tbodyElem.rows.length); trElem.className = "tr" + (j % 2); // first column -> service ID var serviceID = $(this).attr("service__id"); tdElem = trElem.insertCell(trElem.cells.length); tdElem.className = "col0"; tdElem.innerHTML = serviceID; // second column -> service name tdElem = trElem.insertCell(trElem.cells.length); tdElem.className = "col1"; tdElem.innerHTML = "<a href=javascript:showServiceInfo(" + serviceID + ")>" + $(this).find("name").text() + "</a>"; j++; }); // each service } where showServiceInfo retrieves more detailed information about each service from the server based on the serviceID and displays it in the same page as the services table. So far so good. But, it turns out that I have to display the detailed service information in another page rather than the same page as the table. I have creates a generic service_info.html with an empty layout template, but I don't understand how to pass serviceID to this new page so that it gets customized with the detailed service info. How can I do this? Or, is there a better way to handle these situations? Thanks!

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• How do you deserialize a collection with child collections?

  - by Stuart Helwig

  I have a collection of custom entity objects one property of which is an ArrayList of byte arrays. The custom entity is serializable and the collection property is marked with the following attributes: [XmlArray("Images"), XmlArrayItem("Image",typeof(byte[]))] So I serialize a collection of these custom entities and pass them to a web service, as a string. The web service receives the string and byte array in tact, The following code then attempts to deserialize the collection - back into custom entities for processing... XmlSerializer ser = new XmlSerializer(typeof(List<myCustomEntity>)); StringReader reader = new StringReader(xmlStringPassedToWS); List<myCustomEntity> entities = (List<myCustomEntity>)ser.Deserialize(reader); foreach (myCustomEntity e in entities) { // ...do some stuff... foreach (myChildCollection c in entities.ChildCollection { // .. do some more stuff.... } } I've checked the XML resulting from the initial serialization and it does contain byte array - the child collection, as does the StringReader built above. After the deserialization process, the resulting collection of custom entites is fine, except that each object in the collection does not contain any items in its child collection. (i.e. it doesn't get to "...do some more stuff..." above. Can someone please explain what I am doing wrong? Is it possible to serialize ArrayLists within a generic collection of custom entities?

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• how can i handle calculator buutons in c# window form program

  - by sama

  using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace lab8ass1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button11_Click(object sender, EventArgs e) { textBox1.Text += "."; } private void btnone_Click(object sender, EventArgs e) { textBox1.Text += "1"; } private void btnrwo_Click(object sender, EventArgs e) { textBox1.Text += "2"; } private void btnthree_Click(object sender, EventArgs e) { textBox1.Text += "3"; } private void btnfour_Click(object sender, EventArgs e) { textBox1.Text += "4"; } private void btnfive_Click(object sender, EventArgs e) { textBox1.Text += "5"; } private void btnsix_Click(object sender, EventArgs e) { textBox1.Text += "6"; } private void btnseven_Click(object sender, EventArgs e) { textBox1.Text += "7"; } private void btneight_Click(object sender, EventArgs e) { textBox1.Text += "8"; } private void btnnine_Click(object sender, EventArgs e) { textBox1.Text += "9"; } private void btnzero_Click(object sender, EventArgs e) { textBox1.Text += "0"; } string s1,s; private void btnplus_Click(object sender, EventArgs e) { s1 = textBox1.Text; textBox1.Text = ""; s = textBox1.Text; //textBox1.Text } private void btnequal_Click(object sender, EventArgs e) { } } } here my code how can i handle calculator buutons

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• Populate a tree from Hierarchical data using 1 LINQ statement

  - by Midhat

  Hi. I have set up this programming exercise. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication2 { class DataObject { public int ID { get; set; } public int ParentID { get; set; } public string Data { get; set; } public DataObject(int id, int pid, string data) { this.ID = id; this.ParentID = pid; this.Data = data; } } class TreeNode { public DataObject Data {get;set;} public List<DataObject> Children { get; set; } } class Program { static void Main(string[] args) { List<DataObject> data = new List<DataObject>(); data.Add(new DataObject(1, 0, "Item 1")); data.Add(new DataObject(2, 0, "Item 2")); data.Add(new DataObject(21, 2, "Item 2.1")); data.Add(new DataObject(22, 2, "Item 2.2")); data.Add(new DataObject(221, 22, "Item 2.2.1")); data.Add(new DataObject(3, 0, "Item 3")); } } } The desired output is a List of 3 treenodes, having items 1, 2 and 3. Item 2 will have a list of 2 dataobjects as its children member and so on. I have been trying to populate this tree (or rather a forest) using just 1 SLOC using LINQ. A simple group by gives me the desired data but the challenge is to organize it in TreeNode objects. Can someone give a hint or an impossibility result for this?

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• Euler Project Help (Problem 12) - Prime Factors and the like

  - by Richie_W

  I hate to have to ask, but I'm pretty stuck here. I need to test a sequence of numbers to find the first which has over 500 factors: http://projecteuler.net/index.php?section=problems&id=12 -At first I attempted to brute force the answer (finding a number with 480 after a LONG time) -I am now looking at determining the prime factors of a number and then use them to find all other factors. I am currently at the stage where I can get an array of prime factors for any number I input - i.e 300 has the prime factors 2 2 3 5 5 Using this array of prime factors I need to be able to calculate the remaining factors - This is the part I am stuck on. Basically, as I understand it, I need to calculate ALL possible combinations of the numbers in the array... i.e 2 * 2 2 * 2 * 3 2 * 2 * 3 * 5 2 * 3 2 * 3 * 3 ...and so forth - But where it gets interesting is with things like... 2 * 5 2 * 3 * 5 ...i.e Numbers which are not adjacent to each other in the array I can't think of a way to code this in a generic fashion for any length array... I need help! P.S - I am working in Java EDIT: My brute force code - As it has been suggested brute forcing the problem will work and so there may be an error in my code :( package euler.problem12; public class Solution { public static void main(String[] args) { int next = 1; int triangle = 0; int maxFactors = 0; while(true) { triangle = triangle + next; int factors = 1; int max = (int) triangle / 2; for(int i = 1; i <= max; ++i) { if(triangle % i == 0) { factors ++; } } if(factors > maxFactors) { maxFactors = factors; System.out.println(triangle + "\t" + factors); } next++; } } }

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• How Can I Find a List of All Exceptions That a Given Library Function Throws in Python?

  - by b14ck

  Sorry for the long title, but it seems most descriptive for my question. Basically, I'm having a difficult time finding exception information in the official python documentation. For example, in one program I'm currently writing, I'm using the shutil libary's move function: from shutil import move move('somefile.txt', '/tmp/somefile.txt') That works fine, as long as I have write access to /tmp/, there is enough diskspace, and if all other requirements are satisfied. However, when writing generic code, it is often difficult to guarantee those factors, so one usually uses exceptions: from shutil import move try: move('somefile.txt', '/tmp/somefile.txt') except: print 'Move failed for some reason.' I'd like to actually catch the appropriate exceptions thrown instead of just catching everything, but I simply can't find a list of exceptions thrown for most python modules. Is there a way for me to see which exceptions a given function can throw, and why? This way I can make appropriate cases for each exception, eg: from shutil import move try: move('somefile.txt', '/tmp/somefile.txt') except PermissionDenied: print 'No permission.' except DestinationDoesNotExist: print "/tmp/ doesn't exist" except NoDiskSpace: print 'No diskspace available.' Answer points go to whoever can either link me to some relevant documentation that I've somehow overlooked in the official docs, or provide a sure-fire way to figure out exactly which exceptions are thrown by which functions, and why. Thanks!

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• Populate asp.net MVC Index page with data from the database

  - by Sunil Ramu

  I have a web application in which I need to fetch data from the database and display in the index page. As you know, asp.net mvc has given options to edit delete etc... I need to populate the page using the conventional DB way and it uses a stored procedure to retrieve results. I dont want to use LINQ. This is my model entity class using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace LogMVCApp.Models { public class Property { public int Id { get; set; } public string LogInId { get; set; } public string Username { get; set; } public string Action { get; set; } public string Information { get; set; } public bool Passed{get; set; } public string LogType { get; set; } } } and I need to retrieve data using something like this... var conString = ConfigurationManager.ConnectionStrings["connection"].ToString(); var conn = new SqlConnection(conString); var command = new SqlCommand("LogInsert", conn){CommandType=CommandType.StoredProcedure};

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• Using LINQ to map dynamically (or construct projections)

  - by CodeGrue

  I know I can map two object types with LINQ using a projection as so: var destModel = from m in sourceModel select new DestModelType {A = m.A, C = m.C, E = m.E} where class SourceModelType { string A {get; set;} string B {get; set;} string C {get; set;} string D {get; set;} string E {get; set;} } class DestModelType { string A {get; set;} string C {get; set;} string E {get; set;} } But what if I want to make something like a generic to do this, where I don't know specifically the two types I am dealing with. So it would walk the "Dest" type and match with the matching "Source" types.. is this possible? Also, to achieve deferred execution, I would want it just to return an IQueryable. For example: public IQueryable<TDest> ProjectionMap<TSource, TDest>(IQueryable<TSource> sourceModel) { // dynamically build the LINQ projection based on the properties in TDest // return the IQueryable containing the constructed projection } I know this is challenging, but I hope not impossible, because it will save me a bunch of explicit mapping work between models and viewmodels.

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• Visual Studio 2008 Installer, Custom Action. Breakpoint not firing.

  - by Snake

  Hi, I've got an installer with a custom action project. I want the action to fire at install. The action fires, when I write something to the event log, it works perfectly. But I really need to debug the file since the action is quite complicated. So I've got the following installer class: namespace InstallerActions { using System; using System.Collections; using System.Collections.Generic; using System.ComponentModel; using System.Configuration.Install; using System.Diagnostics; using System.IO; [RunInstaller(true)] // ReSharper disable UnusedMember.Global public partial class DatabaseInstallerAction : Installer // ReSharper restore UnusedMember.Global { public DatabaseInstallerAction() { InitializeComponent(); } public override void Install(IDictionary stateSaver) { base.Install(stateSaver); System.Diagnostics.Debugger.Launch(); System.Diagnostics.Debugger.Break(); // none of these work Foo(); } private static void Foo() { } } } The installer just finalizes without warning me, it doesn't break, it doesn't ask me to attach a debugger. I've tried debug and release mode. Am I missing something? Thanks -Snake

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• Modifying C# dictionary value

  - by minjang

  I'm a C++ expert, but not at all for C#. I created a Dictionary<string, STATS>, where STATS is a simple struct. Once I built the dictionary with initial string and STATS pairs, I want to modify the dictionary's STATS value. In C++, it's very clear: Dictionary<string, STATS*> benchmarks; Initialize it... STATS* stats = benchmarks[item.Key]; // Touch stats directly However, I tried like this in C#: Dictionary<string, STATS> benchmarks = new Dictionary<string, STATS>(); // Initialize benchmarks with a bunch of STATS foreach (var item in _data) benchmarks.Add(item.app_name, item); foreach (KeyValuePair<string, STATS> item in benchmarks) { // I want to modify STATS value inside of benchmarks dictionary. STATS stat_item = benchmarks[item.Key]; ParseOutputFile("foo", ref stat_item); // But, not modified in benchmarks... stat_item is just a copy. } This is a really novice problem, but wasn't easy to find an answer. EDIT: I also tried like the following: STATS stat_item = benchmarks[item.Key]; ParseOutputFile(file_name, ref stat_item); benchmarks[item.Key] = stat_item; However, I got the exception since such action invalidates Dictionary: Unhandled Exception: System.InvalidOperationException: Collection was modified; enumeration operation may not execute. at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource) at System.Collections.Generic.Dictionary`2.Enumerator.MoveNext() at helper.Program.Main(String[] args) in D:\dev\\helper\Program.cs:line 75

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• How to specialize template for type derived from particular type

  - by relaxxx

  I have class World which manages creation of object... After creation it calls afterCreation method and I the created object is user-defined type derived from Entity (eg. MyEntity), I want to call addEntity. I the object was something else, I want to do nothing. addEntity must be called with appropriate T, because it generates unique IDs for every derived class etc. Here is my solution: template <int v> struct ToType { enum { value = v }; }; template <typename T> void World::afterCreation(T * t) { afterCreation(t, ToType<std::is_base_of<Entity, T>::value>()); } template <typename T> void World::afterCreation(T * t, ToType<true>) { addEntity(t); //here I cant pass Entity *, I need the real type, eg. MyEntity } template <typename T> void World::afterCreation(T * t, ToType<false>) { } My question is - Can in be done better way? How can I simulate following code without ToType or similar? template <typename T> void afterCreation(){/*generic impl*/} template <typename T where T is derived from Entity> void afterCreation(){/*some specific stuff*/} "specialize" in the title is only to describe my intention, no need to solve problem with template specialization

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• Database Table Schema and Aggregate Roots

  - by bretddog

  Hi, Applicaiton is single user, 1-tier(1 pc), database SqlCE. DataService layer will be (I think) : Repository returning domain objects and quering database with LinqToSql (dbml). There are obviously a lot more columns, this is simplified view. http://img573.imageshack.us/img573/3612/ss20110115171817w.png This is my first attempt of creating a 2 tables database. I think the table schema makes sense, but I need some reassurance or critics. Because the table relations looks quite scary to be honest. I'm hoping you could; Look at the table schema and respond if there are clear signs of troubles or errors that you spot right away.. And if you have time, Look at Program Summary/Questions, and see if the table layout makes makes sense to those points. Please be brutal, I will try to defend :) Program summary: a) A set of categories, each having a set of strategies (1:m) b) Each day a number of items will be produced. And each strategy MAY reference it. (So there can be 50 items, and a strategy may reference 23 of them) c) An item can be referenced by more than one strategy. So I think it's an m:m relation. d) Status values will be logged at fixed time-fractions through the day, for: - .... each Strategy.....each StrategyItem....each item e) An action on an item may be executed by a strategy that reference it. - This is logged as ItemAction (Could have called it StrategyItemAction) User Requsts b) - e) described the main activity mode of the program. To work with only today's DayLog , for each category. 2nd priority activity is retrieval of history, which typically will be From all categories, from day x to day y; Get all StrategyDailyLog. Questions First, does the overall layout look sound? I'm worried to see that there are so many relationships in all directions, connecting everything. Is this normal, or does it look like trouble? StrategyItem is made to represent an m:m relationship. Is it correct as I noted 1:m / 1:1 (marked red) ? StrategyItemTimeLog and ItemTimeLog; Logs values that both need to be retrieved together, when retreiving a StrategyItem. Reason I separated is that the first one is strategy-specific, and several strategies can reference same item. So I thought not to duplicate those values that are not dependent no strategy, but only on the item. Hence I also dragged out the LogTime, as it seems to be the only parameter to unite the logs. But this all looks quite disturbing with those 3 tables. Does it make sense at all? Or you have suggestion? Pink circles shows my vague attempt of Aggregate Root Paths. I've been thinking in terms of "what entity is responsible for delete". Though I'm unsure about the actual root. I think it's Category. Does it make sense related to User Requests described above?

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• OSMF seek with Amazon Cloudfront

  - by giorrrgio

  I've written a little OSMF player that streams via RTMP from Amazon Cloudfront. There's a known issue, the mp3 duration is not correctly readed from metadata and thus the seek function is not working. I know there's a workaround implying the use of getStreamLength function of NetConnection, which I successfully implemented in a previous non-OSMF player, but now I don't know how and when to call it, in terms of OSMF Events and Traits. This code is not working: protected function initApp():void { //the pointer to the media var resource:URLResource = new URLResource( STREAMING_PATH ); // Create a mediafactory instance mediaFactory = new DefaultMediaFactory(); //creates and sets the MediaElement (generic) with a resource and path element = mediaFactory.createMediaElement( resource ); var loadTrait:NetStreamLoadTrait = element.getTrait(MediaTraitType.LOAD) as NetStreamLoadTrait; loadTrait.addEventListener(LoaderEvent.LOAD_STATE_CHANGE, _onLoaded); player = new MediaPlayer( element ); //Marker 5: Add MediaPlayer listeners for media size and current time change player.addEventListener( DisplayObjectEvent.MEDIA_SIZE_CHANGE, _onSizeChange ); player.addEventListener( TimeEvent.CURRENT_TIME_CHANGE, _onProgress ); initControlBar(); } private function onGetStreamLength(result:Object):void { Alert.show("The stream length is " + result + " seconds"); duration = Number(result); } private function _onLoaded(e:LoaderEvent):void { if (e.newState == LoadState.READY) { var loadTrait:NetStreamLoadTrait = player.media.getTrait(MediaTraitType.LOAD) as NetStreamLoadTrait; if (loadTrait && loadTrait.netStream) { var responder:Responder = new Responder(onGetStreamLength); loadTrait.connection.call("getStreamLength", responder, STREAMING_PATH); } } }

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• Stupid newbie c++ two-dimensional array problem.

  - by paulson scott

  I've no idea if this is too newbie or generic for stackoverlflow. Apologies if that's the case, I don't intend to waste time. I've just started working through C++ Primer Plus and I've hit a little stump. This is probably super laughable but: for (int year = 0; year < YEARS; year++) { cout << "Year " << year + 1 << ":"; for (int month = 0; month < MONTHS; month++) { absoluteTotal = (yearlyTotal[year][year] += sales[year][month]); } cout << yearlyTotal[year][year] << endl; } cout << "The total number of books sold over a period of " << YEARS << " years is: " << absoluteTotal << endl; I wish to display the total of all 3 years. The rest of the code works fine: input is fine, individual yearly output is fine but I just can't get 3 years added together for one final total. I did have the total working at one point but I didn't have the individual totals working. I messed with it and reversed the situation. I've been messing with it for God knows how long. Any idea guys? Sorry if this isn't the place!

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