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  • Compare Properties automatically

    - by juergen d
    I want to get the names of all properties that changed for matching objects. I have these (simplified) classes: public enum PersonType { Student, Professor, Employee } class Person { public string Name { get; set; } public PersonType Type { get; set; } } class Student : Person { public string MatriculationNumber { get; set; } } class Subject { public string Name { get; set; } public int WeeklyHours { get; set; } } class Professor : Person { public List<Subject> Subjects { get; set; } } Now I want to get the objects where the Property values differ: List<Person> oldPersonList = ... List<Person> newPersonList = ... List<Difference> = GetDifferences(oldPersonList, newPersonList); public List<Difference> GetDifferences(List<Person> oldP, List<Person> newP) { //how to check the properties without casting and checking //for each type and individual property?? //can this be done with Reflection even in Lists?? } In the end I would like to have a list of Differences like this: class Difference { public List<string> ChangedProperties { get; set; } public Person NewPerson { get; set; } public Person OldPerson { get; set; } } The ChangedProperties should contain the name of the changed properties.

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  • The correct usage of nested #pragma omp for directives

    - by GoldenLee
    The following code runs like a charm before OpenMP parallelization was applied. In fact, the following code was in a state of endless loop! I'm sure that's result from my incorrect use to the OpenMP directives. Would you please show me the correct way? Thank you very much. #pragma omp parallel for for (int nY = nYTop; nY <= nYBottom; nY++) { for (int nX = nXLeft; nX <= nXRight; nX++) { // Use look-up table for performance dLon = theApp.m_LonLatLUT.LonGrid()[nY][nX] + m_FavoriteSVISSRParams.m_dNadirLon; dLat = theApp.m_LonLatLUT.LatGrid()[nY][nX]; // If you don't want to use longitude/latitude look-up table, uncomment the following line //NOMGeoLocate.XYToGEO(dLon, dLat, nX, nY); if (dLon > 180 || dLat > 180) { continue; } if (Navigation.GeoToXY(dX, dY, dLon, dLat, 0) > 0) { continue; } // Skip void data scanline dY = dY - nScanlineOffset; // Compute coefficients as well as its four neighboring points' values nX1 = int(dX); nX2 = nX1 + 1; nY1 = int(dY); nY2 = nY1 + 1; dCx = dX - nX1; dCy = dY - nY1; dP1 = pIRChannelData->operator [](nY1)[nX1]; dP2 = pIRChannelData->operator [](nY1)[nX2]; dP3 = pIRChannelData->operator [](nY2)[nX1]; dP4 = pIRChannelData->operator [](nY2)[nX2]; // Bilinear interpolation usNomDataBlock[nY][nX] = (unsigned short)BilinearInterpolation(dCx, dCy, dP1, dP2, dP3, dP4); } }

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  • Listview not being populated

    - by Luke
    I have put some console.writeline code in to test, but they arent appearing in the output box? public static ArrayList myDeliveries = new ArrayList(); public mainForm() { InitializeComponent(); } private void mainForm_Load(object sender, EventArgs e) { if (!File.Exists("../../MealDeliveries.txt")) { MessageBox.Show("File not found!"); return; } using (StreamReader sr = new StreamReader("../../MealDeliveries.txt")) { //first line is delivery name string strDeliveryName = sr.ReadLine(); Console.WriteLine("some tetttttttttt23423423423423423ttttttttttttttttttttttt"); while (strDeliveryName != null) { //other lines Delivery d = new Delivery(strDeliveryName, sr.ReadLine(), sr.ReadLine(), sr.ReadLine(), sr.ReadLine(), sr.ReadLine(), sr.ReadLine()); mainForm.myDeliveries.Add(d); //check for further values strDeliveryName = sr.ReadLine(); } } displayDeliveries(); } private void displayDeliveries() { lstDeliveryDetails.Items.Clear(); Console.WriteLine("some tettttttttttttttttttttttttttttttttt"); Console.WriteLine(mainForm.myDeliveries.Count); foreach (Delivery d in mainForm.myDeliveries) { lstDeliveryDetails.Items.Add(d.DeliveryName); } } Can anyone help??

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  • when to clear or make null asp .net mvc models?

    - by SARAVAN
    HI, I am working in an asp .net mvc application. I am using the model and storing some of the values which i need to preserve between the page posts, in the form of datacontexts. Say my model looks something like this: public SelectedUser SelectedUserDetails { //get and set has //this.datacontext.data.SelectedUser = ..... //return this.datacontext.data..... } Now when this model needs to be cleared? I have many such models with many properties and datacontext. But I don't have an idea on when to clear it. Is there a way or an event that can be triggered automatically when the model is not used for a long time? Oneway I thought is when i navigate away from a page which uses my underlying model, I can clear that model if its no longer used anywhere and initialise it back as needed. But I need to clear almost many models at many points. Is there an automatic way that can clear models when it is no longer used beacuse care can be taken by my code to initialise them when I need them, but I don't know when to clear them when I no longer need them. I need this to get rid of any memory related issues. Any thoughts or comments?

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  • Organising UI code in .NET forms

    - by sb3700
    Hi I'm someone who has taught myself programming, and haven't had any formal training in .NET programming. A while back, I started C# in order to develop a GUI program to control sensors, and the project has blossomed. I was just wondering how best to organise the code, particularly UI code, in my forms. My forms currently are a mess, or at least seem a mess to me. I have a constructor which initialises all the parameters and creates events. I have a giant State property, which updates the Enabled state of all my form control as users progress through the application (ie: disconnected, connected, setup, scanning) controlled by a States enum. I have 3-10 private variables accessed through properties, some of which have side-effects in changing the values of form elements. I have a lot of "UpdateXXX" functions to handle UI elements that depend on other UI elements - ie: if a sensor is changed, then change the baud rate drop down list. They are separated into regions I have a lot of events calling these Update functions I have a background worker which does all the scanning and analysis. My problem is this seems like a mess, particularly the State property, and is getting unmaintainable. Also, my application logic code and UI code are in the same file and to some degree, intermingled which seems wrong and means I need to do a lot of scrolling to find what I need. How do you structure your .net forms? Thanks

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  • Unable to insert DateTime format into database

    - by melvg
    I'm unable to insert the DateTime into my database. Am i writing the statement wrongly? Apparently without the DateTime, I am able to insert into the database string dateAndTime = date + " " + time; CultureInfo provider = CultureInfo.InvariantCulture; DateTime theDateTime = DateTime.ParseExact(dateAndTime, "d MMMM yyyy hh:mm tt", provider); //Create a connection, replace the data source name with the name of the SQL Anywhere Demo Database that you installed SAConnection myConnection = new SAConnection("UserID=dba;Password=sql;DatabaseName=emaDB;ServerName=emaDB"); //open the connection ; myConnection.Open(); //Create a command object. SACommand insertAccount = myConnection.CreateCommand(); //Specify a query. insertAccount.CommandText = ("INSERT INTO [meetingMinutes] (title,location,perioddate,periodtime,attenders,agenda,accountID,facilitator,datetime) VALUES ('"+title+"','" + location + "', '" + date + "','" + time + "', '" + attender + "','" + agenda + "', '" + accountID + "','" + facilitator + "','" +theDateTime+ "')"); try { insertAccount.ExecuteNonQuery(); if (title == "" || agenda == "") { btnSubmit.Attributes.Add("onclick", "displayIfSuccessfulInsert();"); //ScriptManager.RegisterStartupScript(this, GetType(), "error", "alert('Please ensure to have a title or agenda!');", true); } else { btnSubmit.Attributes.Add("onclick", "displayIfSuccessfulInsert();"); Response.Redirect("HomePage.aspx"); //ScriptManager.RegisterStartupScript(this, this.GetType(), "Redit", "alert('Minutes Created!'); window.location='" + Request.ApplicationPath + "/HomePage.aspx';", true); } } catch (Exception exception) { Console.WriteLine(exception); } finally { myConnection.Close(); } It does not insert the SQL into my database.

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  • Attribute Address getting displayed instead of Attribute Value

    - by Manish
    I am try to create the following. I want to have one drop down menu. Depending on the option selected in the first drop down menu, options in second drop down menu will be displayed. The options in 2nd drop down menu is supposed by dynamic, i.e., options change with the change of values in first menu. Here, instead of getting the drop down menus, I am getting the following Choose your Option1: Choose your Option2: Note: I strictly don't want to use javascript. home_form.py class HomeForm(forms.Form): def __init__(self, *args, **kwargs): var_filter_con = kwargs.pop('filter_con', None) super(HomeForm, self).__init__(*args, **kwargs) if var_filter_con == '***': var_empty_label = None else: var_empty_label = ' ' self.option2 = forms.ModelChoiceField(queryset = db_option2.objects.filter(option1_id = var_filter_con).order_by("name"), empty_label = var_empty_label, widget = forms.Select(attrs={"onChange":'this.form.submit();'}) ) self.option1 = forms.ModelChoiceField(queryset = db_option1.objects.all().order_by("name"), empty_label=None, widget=forms.Select(attrs={"onChange":'this.form.submit();'}) ) view.py def option_view(request): if request.method == 'POST': form = HomeForm(request.POST) if form.is_valid(): cd = form.cleaned_data if cd.has_key('option1'): f = HomeForm(filter_con = cd.get('option1')) return render_to_response('homepage.html', {'home_form':f,}, context_instance=RequestContext(request)) return render_to_response('invalid_data.html', {'form':form,}, context_instance=RequestContext(request)) else: f = HomeForm(filter_con = '***') return render_to_response('homepage.html', {'home_form':f,}, context_instance=RequestContext(request)) homepage.html <!DOCTYPE HTML> <head> <title>Nivaaran</title> </head> <body> <form method="post" name = 'choose_opt' action=""> {% csrf_token %} Choose your Option1: {{ home_form.option1 }} <br/> Choose your Option2: {{ home_form.option2 }} </form> </body>

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  • Boost threading/mutexs, why does this work?

    - by Flamewires
    Code: #include <iostream> #include "stdafx.h" #include <boost/thread.hpp> #include <boost/thread/mutex.hpp> using namespace std; boost::mutex mut; double results[10]; void doubler(int x) { //boost::mutex::scoped_lock lck(mut); results[x] = x*2; } int _tmain(int argc, _TCHAR* argv[]) { boost::thread_group thds; for (int x = 10; x>0; x--) { boost::thread *Thread = new boost::thread(&doubler, x); thds.add_thread(Thread); } thds.join_all(); for (int x = 0; x<10; x++) { cout << results[x] << endl; } return 0; } Output: 0 2 4 6 8 10 12 14 16 18 Press any key to continue . . . So...my question is why does this work(as far as i can tell, i ran it about 20 times), producing the above output, even with the locking commented out? I thought the general idea was: in each thread: calculate 2*x copy results to CPU register(s) store calculation in correct part of array copy results back to main(shared) memory I would think that under all but perfect conditions this would result in some part of the results array having 0 values. Is it only copying the required double of the array to a cpu register? Or is it just too short of a calculation to get preempted before it writes the result back to ram? Thanks.

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  • calculating the index of an array C#

    - by Kerry G
    I want to display a list of the answers a student entered incorrectly. How do I identify the index of these questions? I am hoping to change the contents of a textbox to a list of the questions answered incorrectly, which would require calculating the index of each incorrect question. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace WindowsFormsApplication5 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } //return a pass/fail //return number of correct answers //return number of incorrect answers //return index figures of incorrect values public void examResults () { string[] correctAnswers = {B,D,A,A,C,A,B,A,C,D,B,C,D,A,D,C,C,B,D,A}; string[] studentResults = File.ReadAllLines("studentResults.txt"); var c = correctAnswers.Where((x, i) => x.Equals(studentResults[i])).Count(); if ( c <= 14) passFailBox.Text = "Student has failed the exam"; else passFailBox.Text = "Student has passed the exam"; numberCorrectBox.Text = "Student has answered" + c + "answers correctly"; int f; f= 21-c; numberIncorrectBox.Text = "Student has answered" + f + "answers incorrectly"; } } }

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  • Select rows from table1 and all the children from table2 into an object

    - by Patrick
    I want to pull data from table "Province_Notifiers" and also fetch all corresponding items from table "Province_Notifier_Datas". The table "Province_Notifier" has a guid to identify it (PK), table "Province_Notifier_Datas" has a column called BelongsToProvinceID witch is a foreign key to the "Province_Notifier" tables guid. I tried something like this: var records = from data in ctx.Province_Notifiers where DateTime.Now >= data.SendTime && data.Sent == false join data2 in ctx.Province_Notifier_Datas on data.Province_ID equals data2.BelongsToProvince_ID select new Province_Notifier { Email = data.Email, Province_ID = data.Province_ID, ProvinceName = data.ProvinceName, Sent = data.Sent, UserName = data.UserName, User_ID = data.User_ID, Province_Notifier_Datas = (new List<Province_Notifier_Data>().AddRange(data2)) }; This line is not working and i am trying to figure out how topull the data from table2 into that Province_Notifier_Datas variable. Province_Notifier_Datas = (new List<Province_Notifier_Data>().AddRange(data2)) I can add a record easily by adding the second table row into the Province_Notifier_Datas but i can't fetch it back. Province_Notifier dbNotifier = new Province_Notifier(); // set some values for dbNotifier dbNotifier.Province_Notifier_Datas.Add( new Province_Notifier_Data { BelongsToProvince_ID = userInput.Value.ProvinceId, EventText = GenerateNotificationDetail(notifierDetail) }); This works and inserts the data correctly into both tables. Edit: These error messages is thrown: Cannot convert from 'Province_Notifier_Data' to 'System.Collections.Generic.IEnumerable' If i look in Visual Studio, the variable "Province_Notifier_Datas" is of type System.Data.Linq.EntitySet The best overloaded method match for 'System.Collections.Generic.List.AddRange(System.Collections.Generic.IEnumerable)' has some invalid arguments Edit: var records = from data in ctx.Province_Notifiers where DateTime.Now >= data.SendTime && data.Sent == false join data2 in ctx.Province_Notifier_Datas on data.Province_ID equals data2.BelongsToProvince_ID into data2list select new Province_Notifier { Email = data.Email, Province_ID = data.Province_ID, ProvinceName = data.ProvinceName, Sent = data.Sent, UserName = data.UserName, User_ID = data.User_ID, Province_Notifier_Datas = new EntitySet<Province_Notifier_Data>().AddRange(data2List) }; Error 3 The name 'data2List' does not exist in the current context.

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  • Create Dynamically table at runtime & save it in database

    - by user1548245
    I have written a code for creating table. It displays table structure on GUI form, but what I want is, when I enter values into table it should be stored in database table too. My code: <?php function display($column,$rows) { echo "<table border='1' align='center'>"; for ($iii = 0;$iii <$_POST['column'];$iii++) { echo "<tr>".$jjj."</tr>"; //display no. of <tr> for ($jjj = 0; $jjj <$_POST['rows'];$jjj++) { echo "<td>" ."<input type=\"text\" name='$iii'>"."</td>"; } } echo "</table>"; } ?>

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  • String comparison in Python: is vs. ==

    - by Coquelicot
    I noticed a Python script I was writing was acting squirrelly, and traced it to an infinite loop, where the loop condition was "while line is not ''". Running through it in the debugger, it turned out that line was in fact ''. When I changed it to != rather than 'is not', it worked fine. I did some searching, and found this question, the top answer to which seemed to be just what I needed. Except the answer it gave was counter to my experience. Specifically, the answerer wrote: For all built-in Python objects (like strings, lists, dicts, functions, etc.), if x is y, then x==y is also True. I double-checked the type of the variable, and it was in fact of type str (not unicode or something). Is his answer just wrong, or is there something else afoot? Also, is it generally considered better to just use '==' by default, even when comparing int or Boolean values? I've always liked to use 'is' because I find it more aesthetically pleasing and pythonic (which is how I fell into this trap...), but I wonder if it's intended to just be reserved for when you care about finding two objects with the same id.

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  • Combining two queries on same table

    - by user1830856
    I've looked through several previous questions but I am struggling to apply the solutions to my specific example. I am having trouble combining query 1 and query 2. My query originally returned (amongst other details) the values "SpentTotal" and "UnderSpent" for all members/users for the current month. My issue has been adding two additional columns to this original quert that will return JUST these two columns (Spent and Overspent) but for the previous months data Original Query #1: set @BPlanKey = '##CURRENTMONTH##' EXECUTE @RC = Minimum_UpdateForPeriod @BPlanKey SELECT cm.clubaccountnumber, bp.Description , msh.PeriodMinObligation, msh.SpentTotal, msh.UnderSpent, msh.OverSpent, msh.BilledDate, msh.PeriodStartDate, msh.PeriodEndDate, msh.OverSpent FROM MinimumSpendHistory msh INNER JOIN BillPlanMinimums bpm ON msh.BillingPeriodKey = @BPlanKey and bpm.BillPlanMinimumKey = msh.BillPlanMinimumKey INNER JOIN BillPlans bp ON bp.BillPlanKey = bpm.BillPlanKey INNER JOIN ClubMembers cm ON cm.parentmemberkey is null and cm.ClubMemberKey = msh.ClubMemberKey order by cm.clubaccountnumber asc, msh.BilledDate asc Query #2, query of all columns for PREVIOUS month, but I only need two (spent and over spent), added to the query from above, joined on the customer number: set @BPlanKeyLastMo = '##PREVMONTH##' EXECUTE @RCLastMo = Minimum_UpdateForPeriod @BPlanKeyLastMo SELECT cm.clubaccountnumber, bp.Description , msh.PeriodMinObligation, msh.SpentTotal, msh.UnderSpent, msh.OverSpent, msh.BilledDate, msh.PeriodStartDate, msh.PeriodEndDate, msh.OverSpent FROM MinimumSpendHistory msh INNER JOIN BillPlanMinimums bpm ON msh.BillingPeriodKey = @BPlanKeyLastMo and bpm.BillPlanMinimumKey = msh.BillPlanMinimumKey INNER JOIN BillPlans bp ON bp.BillPlanKey = bpm.BillPlanKey INNER JOIN ClubMembers cm ON cm.parentmemberkey is null and cm.ClubMemberKey = msh.ClubMemberKey order by cm.clubaccountnumber asc, msh.BilledDate asc Big thank you to any and all that are willing to lend their help and time. Cheers! AJ CREATE TABLE MinimumSpendHistory( [MinimumSpendHistoryKey] [uniqueidentifier] NOT NULL, [BillPlanMinimumKey] [uniqueidentifier] NOT NULL, [ClubMemberKey] [uniqueidentifier] NOT NULL, [BillingPeriodKey] [uniqueidentifier] NOT NULL, [PeriodStartDate] [datetime] NOT NULL, [PeriodEndDate] [datetime] NOT NULL, [PeriodMinObligation] [money] NOT NULL, [SpentTotal] [money] NOT NULL, [CurrentSpent] [money] NOT NULL, [OverSpent] [money] NULL, [UnderSpent] [money] NULL, [BilledAmount] [money] NOT NULL, [BilledDate] [datetime] NOT NULL, [PriorPeriodMinimum] [money] NULL, [IsCommitted] [bit] NOT NULL, [IsCalculated] [bit] NOT NULL, [BillPeriodMinimumKey] [uniqueidentifier] NOT NULL, [CarryForwardCounter] [smallint] NULL, [YTDSpent] [money] NOT NULL, [PeriodToAccumulateCounter] [int] NULL, [StartDate] [datetime] NOT NULL,

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  • create a class attribute without going through __setattr__

    - by eric.frederich
    Hello, What I have below is a class I made to easily store a bunch of data as attributes. They wind up getting stored in a dictionary. I override __getattr__ and __setattr__ to store and retrieve the values back in different types of units. When I started overriding __setattr__ I was having trouble creating that initial dicionary in the 2nd line of __init__ like so... super(MyDataFile, self).__setattr__('_data', {}) My question... Is there an easier way to create a class level attribute with going through __setattr__? Also, should I be concerned about keeping a separate dictionary or should I just store everything in self.__dict__? #!/usr/bin/env python from unitconverter import convert import re special_attribute_re = re.compile(r'(.+)__(.+)') class MyDataFile(object): def __init__(self, *args, **kwargs): super(MyDataFile, self).__init__(*args, **kwargs) super(MyDataFile, self).__setattr__('_data', {}) # # For attribute type access # def __setattr__(self, name, value): self._data[name] = value def __getattr__(self, name): if name in self._data: return self._data[name] match = special_attribute_re.match(name) if match: varname, units = match.groups() if varname in self._data: return self.getvaras(varname, units) raise AttributeError # # other methods # def getvaras(self, name, units): from_val, from_units = self._data[name] if from_units == units: return from_val return convert(from_val, from_units, units), units def __str__(self): return str(self._data) d = MyDataFile() print d # set like a dictionary or an attribute d.XYZ = 12.34, 'in' d.ABC = 76.54, 'ft' # get it back like a dictionary or an attribute print d.XYZ print d.ABC # get conversions using getvaras or using a specially formed attribute print d.getvaras('ABC', 'cm') print d.XYZ__mm

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  • How do I fix the alpha value after calling GDI text functions?

    - by Daniel Stutzbach
    I have a application that uses the Aero glass effect, so each pixel has an alpha value in addition to red, green, and blue values. I have one custom-draw control that has a solid white background (alpha = 255). I would like to draw solid text on the control using the GDI text functions. However, these functions set the alpha value to an arbitrary value, causing the text to translucently show whatever window is beneath my application's. After calling rendering the text, I would like to go through all of the pixels in the control and set their alpha value back to 255. What's the best way to do that? I haven't had any luck with the BitBlt, GetPixel, and SetPixel functions. They appear to be oblivious to the alpha value. Here are other solutions that I have considered and rejected: Draw to a bitmap, then copy the bitmap to the device: With this approach, the text rendering does not make use of the characteristics of the monitor (e.g., ClearText). Use GDI+ for text rendering: This application originally used GDI+ for text rendering (before I started working on Aero support). I switched to GDI because of difficulties I encountered trying to accurately measure strings with GDI+. I'd rather not switch back. Set the Aero region to avoid the control in question: My application's window is actually a child window of a different application running in a different process. I don't have direct control over the Aero settings on the top-level window. The application is written in C# using Windows Forms, though I'm not above using Interop to call Win32 API functions.

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  • How to access the members of this data in PHP?

    - by George Edison
    Okay. Now I give up. I have been playing with this for hours. I have a variable name $data. The variable contains these contents: (extracted by using var_export()) array ( 'headers' => array ( 'content-type' => 'multipart/alternative; boundary="_689e1a7d-7a0a-442a-bd6c-a1fb1dc2993e_"', ), 'ctype_parameters' => array ( 'boundary' => '_689e1a7d-7a0a-442a-bd6c-a1fb1dc2993e_', ), 'parts' => array ( 0 => stdClass::__set_state(array( 'headers' => array ( 'content-type' => 'text/plain; charset="iso-8859-1"', 'content-transfer-encoding' => 'quoted-printable', ), 'ctype_primary' => 'text', )), ), ) I removed some non-essential data. I want to access the headers value (on the second line above) - simple: $data->headers I want to access the headers value (on the fourteenth line after the stdClass:: stuff) - how? How can I possibly access the values within the stdClass::__set_state section? I tried var_export($data->parts); but all I get is NULL

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  • C#: Need one of my classes to trigger an event in another class to update a text box

    - by Matt
    Total n00b to C# and events although I have been programming for a while. I have a class containing a text box. This class creates an instance of a communication manager class that is receiving frames from the Serial Port. I have this all working fine. Every time a frame is received and its data extracted, I want a method to run in my class with the text box in order to append this frame data to the text box. So, without posting all of my code I have my form class... public partial class Form1 : Form { CommManager comm; public Form1() { InitializeComponent(); comm = new CommManager(); } private void updateTextBox() { //get new values and update textbox } . . . and I have my CommManager class class CommManager { //here we manage the comms, recieve the data and parse the frame } SO... essentially, when I parse that frame, I need the updateTextBox method from the form class to run. I'm guessing this is possible with events but I can't seem to get it to work. I tried adding an event handler in the form class after creating the instance of CommManager as below... comm = new CommManager(); comm.framePopulated += new EventHandler(updateTextBox); ...but I must be doing this wrong as the compiler doesn't like it... Any ideas?!

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  • How do C++ compilers actually pass reference parameters?

    - by T.E.D.
    This question came about as a result of some mixed-langauge programming. I had a Fortran routine I wanted to call from C++ code. Fortran passes all its parameters by reference (unless you tell it otherwise). So I thought I'd be clever (bad start right there) in my C++ code and define the Fortran routine something like this: extern "C" void FORTRAN_ROUTINE (unsigned & flag); This code worked for a while but (of course right when I needed to leave) suddenly started blowing up on a return call. Clear indication of a munged call stack. Another engineer came behind me and fixed the problem, declaring that the routine had to be deinfed in C++ as extern "C" void FORTRAN_ROUTINE (unsigned * flag); I'd accept that except for two things. One is that it seems rather counter-intuitive for the compiler to not pass reference parameters by reference, and I can find no documentation anywhere that says that. The other is that he changed a whole raft of other code in there at the same time, so it theoretically could have been another change that fixed whatever the issue was. So the question is, how does C++ actually pass reference parameters? Is it perhaps free to do copy-in, copy-out for small values or something? In other words, are reference parameters utterly useless in mixed-language programming? I'd like to know so I don't make this same code-killing mistake ever again.

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  • Performance of a get unique elements/group by operation on an IEnumerable<T>.

    - by tolism7
    I was wondering how could I improve the performance of the following code: public class MyObject { public int Year { get; set; } } //In my case I have 30000 IEnumerable<MyObject> data = MethodThatReturnsManyMyObjects(); var groupedByYear = data.GroupBy(x => x.Year); //Here is the where it takes around 5 seconds foreach (var group in groupedByYear) //do something here. The idea is to get a set of objects with unique year values. In my scenario there are only 6 years included in the 30000 items in the list so the foreach loop will be executed 6 times only. So we have many items needing to be grouped in a few groups. Using the .Distinct() with an explicit IEqualityComparer would be an alternative but somehow I feel that it wont make any difference. I can understand if 30000 items is too much and that i should be happy with the 5 seconds I get, but I was wondering if the above can be imporved performance wise. Thanks.

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  • Factorial function - design and test.

    - by lukas
    I'm trying to nail down some interview questions, so I stared with a simple one. Design the factorial function. This function is a leaf (no dependencies - easly testable), so I made it static inside the helper class. public static class MathHelper { public static int Factorial(int n) { Debug.Assert(n >= 0); if (n < 0) { throw new ArgumentException("n cannot be lower that 0"); } Debug.Assert(n <= 12); if (n > 12) { throw new OverflowException("Overflow occurs above 12 factorial"); } //by definition if (n == 0) { return 1; } int factorialOfN = 1; for (int i = 1; i <= n; ++i) { //checked //{ factorialOfN *= i; //} } return factorialOfN; } } Testing: [TestMethod] [ExpectedException(typeof(OverflowException))] public void Overflow() { int temp = FactorialHelper.MathHelper.Factorial(40); } [TestMethod] public void ZeroTest() { int factorialOfZero = FactorialHelper.MathHelper.Factorial(0); Assert.AreEqual(1, factorialOfZero); } [TestMethod] public void FactorialOf5() { int factOf5 = FactorialHelper.MathHelper.Factorial(5); Assert.AreEqual(120,factOf5); } [TestMethod] [ExpectedException(typeof(ArgumentException))] public void NegativeTest() { int factOfMinus5 = FactorialHelper.MathHelper.Factorial(-5); } I have a few questions: Is it correct? (I hope so ;) ) Does it throw right exceptions? Should I use checked context or this trick ( n 12 ) is ok? Is it better to use uint istead of checking for negative values? Future improving: Overload for long, decimal, BigInteger or maybe generic method? Thank you

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  • error catching exception while System.out.print

    - by user1702633
    I have 2 classes, one that implements a double lookup( int i); and one where I use that lookup(int i) in solving a question, or in this case printing the lookup values. This case is for an array. So I read the exception documentation or google/textbook and come with the following code: public double lookup(int i) throws Exception { if( i > numItems) throw new Exception("out of bounds"); return items[i]; } and take it over to my class and try to print my set, where set is a name of the object type I define in the class above. public void print() { for (int i = 0; i < set.size() - 1; i++) { System.out.print(set.lookup(i) + ","); } System.out.print(set.lookup(set.size())); } I'm using two print()'s to avoid the last "," in the print, but am getting an unhandled exception Exception (my exception's name was Exception) I think I have to catch my exception in my print() but cannot find the correct formatting online. Do I have to write catch exception Exception? because that gives me a syntax error saying invalid type on catch. Sources like http://docs.oracle.com/javase/tutorial/essential/exceptions/ are of little help to me, I'm can't seem to grasp what the text is telling me. I'm also having trouble finding sources with multiple examples where I can actually understand the coding in the examples. so could anybody give me a source/example for the above catch phrase and perhaps a decent source of examples for new Java programmers? my book is horrendous and I cannot seem to find an understandable example for the above catch phrase online.

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  • Adding up fractions in PHP

    - by Gamemorize
    I would like to create a loop that keeps adding a set fraction, here in my example 1/3, and which later I can check against for matches with integer values. Obviously when php adds 1/3 + 1/3 + 1/3 the result is 0.9999999, so i thought I could use the occasional round to help me, but this isn't working either. The idea that I had would be that .333 + .333 becomes .666 and that if rounded that would become .667, then + .333 and the result is 1. However round only seems to work, for me, if the number of digits actually decreases. so round (0.666, 3) remains 0.666 <?php $denom = 3; $frac = 1/$denom; $frac = round($frac,3); $value = 0; $max =24; for($f = 1; $f <= $max; $f++){ echo "old value is now at ".$value.".<br/>"; $value = $value+$frac; echo "value is now at ".$value.".<br/>"; $value = round($value,3); echo "rounded value is now at ".$value.".<br/>"; $valueArray[$f] = $value; //and here for ease of testing.... if (($value==1)OR ($value==2)OR ($value==3)OR ($value==4)OR ($value==5)OR ($value==6)OR ($value==7)OR ($value==8)){ echo "match!<br/>"; }else{ echo "no match!<br/>"; } } ?> Am I going about this in a totally stupid way? Accuracy when the value is not an integer is not needed, just that it can == with integers.

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  • Best practices for encrytping continuous/small UDP data

    - by temp
    Hello everyone, I am having an application where I have to send several small data per second through the network using UDP. The application need to send the data in real-time (on waiting). I want to encrypt these data and insure that what I am doing is as secure as possible. Since I am using UDP, there is no way to use SSL/TLS, so I have to encrypt each packet alone since the protocol is connectionless/unreliable/unregulated. Right now, I am using a 128-bit key derived from a passphrase from the user, and AES in CBC mode (PBE using AES-CBC). I decided to use a random salt with the passphrase to derive the 128-bit key (prevent dictionary attack on the passphrase), and of course use IVs (to prevent statistical analysis for packets). However I am concerned about few things: Each packet contains small amount of data (like a couple of integer values per packet) which will make the encrypted packets vulnerable to known-plaintext attacks (which will result in making it easier to crack the key). Also, since the encryption key is derived from a passphrase, this will make the key space way less (I know the salt will help, but I have to send the salt through the network once and anyone can get it). Given these two things, anyone can sniff and store the sent data, and try to crack the key. Although this process might take some time, once the key is cracked all the stored data will be decrypted, which will be a real problem for my application. So my question is, what is the best practices for sending/encrypting continuous small data using a connectionless protocol (UDP)? Is my way the best way to do it? ...flowed? ...Overkill? ... Please note that I am not asking for a 100% secure solution, as there is no such thing. Cheers

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  • Two entities with @ManyToOne joins the same table

    - by Ivan Yatskevich
    I have the following entities Student @Entity public class Student implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Teacher @Entity public class Teacher implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Task @Entity public class Task implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "student_id") }) private Student author; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "teacher_id") }) private Teacher curator; //getters and setters } Consider that author and curator are already stored in DB and both are in the attached state. I'm trying to persist my Task: Task task = new Task(); task.setAuthor(author); task.setCurator(curator); entityManager.persist(task); Hibernate executes the following SQL: insert into student_task (teacher_id, id) values (?, ?) which, of course, leads to null value in column "student_id" violates not-null constraint Can anyone explain this issue and possible ways to resolve it?

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  • Why is my code stopping and not returning an exception?

    - by BeckyLou
    I have some code that starts a couple of threads to let them execute, then uses a while loop to check for the current time passing a set timeout period, or for the correct number of results to have been processed (by checking an int on the class object) (with a Thread.Sleep() to wait between loops) Once the while loop is set to exit, it calls Abort() on the threads and should return data to the function that calls the method. When debugging and stepping through the code, I find there can be exceptions in the code running on the separate threads, and in some cases I handle these appropriately, and at other times I don't want to do anything specific. What I have been seeing is that my code goes into the while loop and the thread sleeps, then nothing is returned from my function, either data or an exception. Code execution just stops completely. Any ideas what could be happening? Code sample: System.Threading.Thread sendThread = new System.Threading.Thread(new System.Threading.ThreadStart(Send)); sendThread.Start(); System.Threading.Thread receiveThread = new System.Threading.Thread(new System.Threading.ThreadStart(Receive)); receiveThread.Start(); // timeout Int32 maxSecondsToProcess = this.searchTotalCount * timeout; DateTime timeoutTime = DateTime.Now.AddSeconds(maxSecondsToProcess); Log("Submit() Timeout time: " + timeoutTime.ToString("yyyyMMdd HHmmss")); // while we're still waiting to receive results & haven't hit the timeout, // keep the threads going while (resultInfos.Count < this.searchTotalCount && DateTime.Now < timeoutTime) { Log("Submit() Waiting..."); System.Threading.Thread.Sleep(10 * 1000); // 1 minute } Log("Submit() Aborting threads"); // <== this log doesn't show up sendThread.Abort(); receiveThread.Abort(); return new List<ResultInfo>(this.resultInfos.Values);

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