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  • c# inheriting generic collection and serialization...

    - by Stecy
    Hi, The setup: class Item { private int _value; public Item() { _value = 0; } public int Value { get { return _value; } set { _value = value; } } } class ItemCollection : Collection<Item> { private string _name; public ItemCollection() { _name = string.Empty; } public string Name { get {return _name;} set {_name = value;} } } Now, trying to serialize using the following code fragment: ItemCollection items = new ItemCollection(); ... XmlSerializer serializer = new XmlSerializer(typeof(ItemCollection)); using (FileStream f = File.Create(fileName)) serializer.Serialize(f, items); Upon looking at the resulting XML I see that the ItemCollection.Name value is not there! I think what may be happening is that the serializer sees the ItemCollection type as a simple Collection thus ignoring any other added properties... Is there anyone having encountered such a problem and found a solution? Regards, Stécy

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  • SML/NJ incomplete match

    - by dimvar
    I wonder how people handle nonexhaustive match warnings in the SML/NJ compiler. For example, I may define a datatype datatype DT = FOO of int | BAR of string and then have a function that I know only takes FOOs fun baz (FOO n) = n + 1 The compiler will give a warning stdIn:1.5-1.24 Warning: match nonexhaustive FOO n = ... val baz = fn : DT - int I don't wanna see warnings for incomplete matches I did on purpose, because then I have to scan through the output to find a warning that might actually be a bug. I can write the function like this fun baz (FOO n) = n + 1 | baz _ = raise Fail "baz" but this clutters the code. What do people usually do in this situation?

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  • Agilent E4426B signal generator locks up during multiple GPIB *SAV operations

    - by aspiehler
    I have a test fixture with an Agilent E4426B RF signal generator connected to a PC via a National Instrument Ethernet-to-GPIB bridge. My software is attempting to sanitize the instrument by presetting it and then saving the current state to all of the memory locations writable via the standard SCPI command "*SAV x,y". The loop works to a point, but eventually the instrument responds with an error and continuously displays the "L" icon on the front display and a "Remote preset" message at the bottom. At that point it won't respond to any more remote commands and I have to either cycle power or press LOCAL, then PRESET at which point it takes about 3 minutes to finish presetting. At that point the "L" icon is still present and and the next GPIB command sent to the instrument causes it to report a -113 error (undefined header) in the instrument error queue. I fired up NI spy to see what was happening, and found that the error was happening at the same point in the loop - "*SAV 6,2" in this case. From NI Spy: Send (0, 0x0017, "*SAV 6,2", 8 (0x8), NLend (0,0x01)) Process ID: 0x00000520 Thread ID: 0x00000518 ibsta:0xc168 iberr: 6 ibcntl: 2(0x2) And here's the code from the instrument driver: int CHP_E4426b::Erase() { if ((m_StatusCode = Initialize()) != GPIB_SUCCESS) // basically just sends "*RST" return m_StatusCode; m_SaveState = "*SAV %d, %d"; for (int i=0; i < 10; i++) for (int j=0; j < 100; j++) { sprintf(m_CmdString, m_SaveState, j, i); if ((m_StatusCode = Send(m_CmdString, strlen(m_CmdString))) != GPIB_SUCCESS) return m_StatusCode; } return GPIB_SUCCESS; } I tried putting a small Sleep() delay (10-20 ms) at the end of the inner loop, and to my surprise it caused the error to show up earlier rather than later. 10 ms caused the loop to error out at 44,1 and 20 ms was even sooner. I've already eliminated faulty cabling or the instrument as the culprit. This same type of sequence works without any error on a higher end signal generator, so I'm tempted to chalk this up to a bug in the instrument's firmware.

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  • Create WPF TextBox that accepts only numbers

    - by Elad
    I would like to create a TextBox that only accepts numeric values, in a specific range. What is the best way to implement such TextBox? I thought about deriving TextBox and to override the validation and coercion of the TextProperty. However, I am not sure how to do this, and I understand that deriving WPF control is generally not recommended. Edit: What I needed was a very basic textbox that filters out all key presses which are not digits. The easiest way to achieve it is to handle the TextBox.PreviewTextInput event: private void textBox_PreviewTextInput(object sender, TextCompositionEventArgs e) { int result; if (!validateStringAsNumber(e.Text,out result,false)) { e.Handled = true; } } (validateStringAsNumber is my function that primarily use Int.TryParse) Some of the suggested solutions are probably better, but for the simple functionality I needed this solution is the easiest and quickest to implement while sufficient for my needs.

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  • How ca I return a value from a function

    - by Shadi Al Mahallawy
    I used a function to calculate information about certain instructions I intialized in a map,like this void get_objectcode(char*&token1,const int &y) { map<string,int> operations; operations["ADD"] = 18; operations["AND"] = 40; operations["COMP"] = 28; operations["DIV"] = 24; operations["J"] = 0X3c; operations["JEQ"] =30; operations["JGT"] =34; operations["JLT"] =38; operations["JSUB"] =48; operations["LDA"] =00; operations["LDCH"] =50; operations["LDL"] =55; operations["LDX"] =04; operations["MUL"] =20; operations["OR"] =44; operations["RD"] =0xd8; operations["RSUB"] =0x4c; operations["STA"] =0x0c; operations["STCH"] =54; operations["STL"] =14; operations["STSW"] =0xe8; operations["STX"] =10; operations["SUB"] =0x1c; operations["TD"] =0xe0; operations["TIX"] =0x2c; operations["WD"] =0xdc; if ((operations.find("ADD")->first==token1)||(operations.find("AND")->first==token1)||(operations.find("COMP")->first==token1) ||(operations.find("DIV")->first==token1)||(operations.find("J")->first==token1)||(operations.find("JEQ")->first==token1) ||(operations.find("JGT")->first==token1)||(operations.find("JLT")->first==token1)||(operations.find("JSUB")->first==token1) ||(operations.find("LDA")->first==token1)||(operations.find("LDCH")->first==token1)||(operations.find("LDL")->first==token1) ||(operations.find("LDX")->first==token1)||(operations.find("MUL")->first==token1)||(operations.find("OR")->first==token1) ||(operations.find("RD")->first==token1)||(operations.find("RSUB")->first==token1)||(operations.find("STA")->first==token1)||(operations.find("STCH")->first==token1)||(operations.find("STCH")->first==token1)||(operations.find("STL")->first==token1) ||(operations.find("STSW")->first==token1)||(operations.find("STX")->first==token1)||(operations.find("SUB")->first==token1) ||(operations.find("TD")->first==token1)||(operations.find("TIX")->first==token1)||(operations.find("WD")->first==token1)) { int y=operations.find(token1)->second; //cout<<hex<<y<<endl; } return ; } which if I cout y in the function gives me an answer just fine which is what i need but there is a problem tring to return the value from the function so that I could use it outside the function , it gives a whole different answer, what is the problem

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  • Rails Joins and include columns from joins table

    - by seth.vargo
    I don't understand how to get the columns I want from rails. I have two models - A User and a Profile. A User :has_many Profile (because users can revert back to an earlier version of their profile): > DESCRIBE users; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | username | varchar(255) | NO | UNI | NULL | | | password | varchar(255) | NO | | NULL | | | last_login | datetime | YES | | NULL | | +----------------+--------------+------+-----+---------+----------------+   > DESCRIBE profiles; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | user_id | int(11) | NO | MUL | NULL | | | first_name | varchar(255) | NO | | NULL | | | last_name | varchar(255) | NO | | NULL | | | . . . . . . | | . . . . . . | | . . . . . . | +----------------+--------------+------+-----+---------+----------------+ In SQL, I can run the query: > SELECT * FROM profiles JOIN users ON profiles.user_id = users.id LIMIT 1; +----+-----------+----------+---------------------+---------+---------------+-----+ | id | username | password | last_login | user_id | first_name | ... | +----+-----------+----------+---------------------+---------+---------------+-----+ | 1 | john | ****** | 2010-12-30 18:04:28 | 1 | John | ... | +----+-----------+----------+---------------------+---------+---------------+-----+ See how I get all the columns for BOTH tables JOINED together? However, when I run this same query in Rails, I don't get all the columns I want - I only get those from Profile: # in rails console >> p = Profile.joins(:user).limit(1) >> [#<Profile ...>] >> p.first_name >> NoMethodError: undefined method `first_name' for #<ActiveRecord::Relation:0x102b521d0> from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.1/lib/active_record/relation.rb:373:in `method_missing' from (irb):8 # I do NOT want to do this (AKA I do NOT want to use "includes") >> p.user >> NoMethodError: undefined method `user' for #<ActiveRecord::Relation:0x102b521d0> from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.1/lib/active_record/relation.rb:373:in method_missing' from (irb):9 I want to (efficiently) return an object that has all the properties of Profile and User together. I don't want to :include the user because it doesn't make sense. The user should always be part of the most recent profile as if they were fields within the Profile model. How do I accomplish this?

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  • SQL: select random row from table where the ID of the row isn't in another table?

    - by johnrl
    I've been looking at fast ways to select a random row from a table and have found the following site: http://74.125.77.132/search?q=cache:http://jan.kneschke.de/projects/mysql/order-by-rand/&hl=en&strip=1 What I want to do is to select a random url from my table 'urls' that I DON'T have in my other table 'urlinfo'.The query I am using now selects a random url from 'urls' but I need it modified to only return a random url that is NOT in the 'urlinfo' table. Heres the query: SELECT url FROM urls JOIN (SELECT CEIL(RAND() * (SELECT MAX(urlid) FROM urls ) ) AS urlid ) AS r2 USING(urlid); And the two tables: CREATE TABLE urls ( urlid INT NOT NULL AUTO_INCREMENT PRIMARY KEY, url VARCHAR(255) NOT NULL, ) ENGINE=INNODB; CREATE TABLE urlinfo ( urlid INT NOT NULL PRIMARY KEY, urlinfo VARCHAR(10000), FOREIGN KEY (urlid) REFERENCES urls (urlid) ) ENGINE=INNODB;

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  • Providing localized error messages for non-attributed model validation in ASP.Net MVC 2?

    - by Lance McNearney
    I'm using the DataAnnotations attributes along with ASP.Net MVC 2 to provide model validation for my ViewModels: public class ExamplePersonViewModel { [Required(ErrorMessageResourceName = "Required", ErrorMessageResourceType = typeof(Resources.Validation))] [StringLength(128, ErrorMessageResourceName = "StringLength", ErrorMessageResourceType = typeof(Resources.Validation))] [DataType(DataType.Text)] public string Name { get; set; } [Required(ErrorMessageResourceName = "Required", ErrorMessageResourceType = typeof(Resources.Validation))] [DataType(DataType.Text)] public int Age { get; set; } } This seems to work as expected (although it's very verbose). The problem I have is that there are behind-the-scenes model validations being performed that are not tied to any specific attribute. An example of this in the above model is that the Age property needs to be an int. If you try to enter a non-integer value on the form, it will error with the following (non-localized) message: The field Age must be a number. How can these non-attribute validation messages be localized? Is there a full list of these messages available so I can make sure they are all localized?

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  • LevelToVisibilityConverter in silverligt 4

    - by prince23
    <UserControl x:Class="SLGridImage.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"> <UserControl.Resources> <local:LevelToVisibilityConverter x:Key="LevelToVisibility" /> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="White"> <sdk:DataGrid x:Name="dgMarks" CanUserResizeColumns="False" SelectionMode="Single" AutoGenerateColumns="False" VerticalAlignment="Top" ItemsSource="{Binding MarkCollection}" IsReadOnly="True" Margin="13,44,0,0" RowDetailsVisibilityMode="Collapsed" Height="391" HorizontalAlignment="Left" Width="965" VerticalScrollBarVisibility="Visible" > <sdk:DataGrid.Columns> <sdk:DataGridTemplateColumn> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate> <Button x:Name="myButton" Click="myButton_Click"> <StackPanel Orientation="Horizontal"> <Image Margin="2, 2, 2, 2" x:Name="imgMarks" Stretch="Fill" Width="12" Height="12" Source="Images/test.png" VerticalAlignment="Center" HorizontalAlignment="Center" Visibility="{Binding Level, Converter={StaticResource LevelToVisibility}}" /> <TextBlock Text="{Binding Level}" TextWrapping="NoWrap" ></TextBlock> </StackPanel> </Button> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> <sdk:DataGridTemplateColumn Header="Name" > <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate > <Border> <TextBlock Text="{Binding Name}" /> </Border> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> <sdk:DataGridTemplateColumn Header="Marks" Width="80"> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate> <Border> <TextBlock Text="{Binding Marks}" /> </Border> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> </sdk:DataGrid.Columns> </sdk:DataGrid> </Grid> </UserControl> in .cs using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.Collections.ObjectModel; using System.ComponentModel; namespace SLGridImage { public partial class MainPage : UserControl { private MarksViewModel model = new MarksViewModel(); public MainPage() { InitializeComponent(); this.DataContext = model; } private void myButton_Click(object sender, RoutedEventArgs e) { } } public class MarksViewModel : INotifyPropertyChanged { public MarksViewModel() { markCollection.Add(new Mark() { Name = "ABC", Marks = 23, Level = 0 }); markCollection.Add(new Mark() { Name = "XYZ", Marks = 67, Level = 1 }); markCollection.Add(new Mark() { Name = "YU", Marks = 56, Level = 0 }); markCollection.Add(new Mark() { Name = "AAA", Marks = 89, Level = 1 }); } private ObservableCollection<Mark> markCollection = new ObservableCollection<Mark>(); public ObservableCollection<Mark> MarkCollection { get { return this.markCollection; } set { this.markCollection = value; OnPropertyChanged("MarkCollection"); } } public event PropertyChangedEventHandler PropertyChanged; public void OnPropertyChanged(string propName) { if (PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(propName)); } } public class Mark { public string Name { get; set; } public int Marks { get; set; } public int Level { get; set; } } public class LevelToVisibilityConverter : System.Windows.Data.IValueConverter { #region IValueConverter Members public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { Visibility isVisible = Visibility.Collapsed; if ((value == null)) return isVisible; int condition = (int)value; isVisible = condition == 1 ? Visibility.Visible : Visibility.Collapsed; return isVisible; } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } #endregion } } when i run getting error The type 'local:LevelToVisibilityConverter' was not found. Verify that you are not missing an assembly reference and that all referenced assemblies have been built. what i am i missing here looking forward for an solution thank you

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  • Undefined Behavior and Sequence Points Reloaded

    - by Nawaz
    Consider this topic a sequel of the following topic: Previous Installment Undefined Behavior and Sequence Points Let's revisit this funny and convoluted expression (the italicized phrases are taken from the above topic *smile* ): i += ++i; We say this invokes undefined-behavior. I presume that when say this, we implicitly assume that type of i is one of built-in types. So my question is: what if the type of i is a user-defined type? Say it's type is Index which is defined later in this post (see below). Would it still invoke undefined-behavior? If yes, why? Is it not equivalent to writing i.operator+=(i.operator ++()); or even syntactically simpler i.add(i.inc());? Or, do they too invoke undefined-behavior? If no, why not? After all, the object i gets modified twice between consecutive sequence points. Please recall the rule of thumb : an expression can modify an object's value only once between consecutive "sequence points. And if i += ++i is an expression, then it must invoke undefined-behavior. If so, then it's equivalents i.operator+=(i.operator ++()); and i.add(i.inc()); must also invoke undefined-behavior which seems to be untrue! (as far as I understand) Or, i += ++i is not an expression to begin with? If so, then what is it and what is the definition of expression? If it's an expression, and at the same time, it's behavior is also well-defined, then it implies that number of sequence points associated with an expression somehow depends on the type of operands involved in the expression. Am I correct (even partly)? By the way, how about this expression? a[++i] = i; //taken from the previous topic. but here type of `i` is Index. class Index { int state; public: Index(int s) : state(s) {} Index& operator++() { state++; return *this; } Index& operator+=(const Index & index) { state+= index.state; return *this; } operator int() { return state; } Index & add(const Index & index) { state += index.state; return *this; } Index & inc() { state++; return *this; } };

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  • How to pass the structure to a function in C++ defined in another class?

    - by Dany
    I have a class Con as this:- class Con { public: struct MachineList { BSTR AccountId; BSTR MachineId; BSTR Make; char* Make1; BSTR Model; char* Model1; BSTR SerialNumber; BSTR IpAddress; char* IpAddress1; BSTR Port; int Port1; BSTR LocationCode; } machinelist[100] ; int w; } ; i created an object of Con class as Con m_con; I have another class Test class Test { public: void fun();//i want to pass the object of the structure that i created in Con //what arguments should i pass in fun function? };

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  • Error while excuting a simple boost thread program

    - by Eternal Learner
    Hi All, Could you tell mw what is the problem with the below boost::thread program #include<iostream> #include<boost/thread/thread.hpp> boost::mutex mutex; class A { public: A() : a(0) {} void operator()() { boost::mutex::scoped_lock lock(mutex); } private: int a; }; int main() { boost::thread thr1(A()); boost::thread thr2(A()); thr1.join(); thr2.join(); } I get the error message: error: request for member 'join' in 'thr1', which is of non-class type 'boost::thread()(A ()())' BoostThread2.cpp:30: error: request for member 'join' in 'thr2', which is of non-class type 'boost::thread ()(A ()())'

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  • How to format a function pointer?

    - by Longpoke
    Is there any way to print a pointer to a function in ANSI C? Of course this means you have to cast the function pointer to void pointer, but it appears that's not possible?? #include <stdio.h> int main() { int (*funcptr)() = main; printf("%p\n", (void* )funcptr); printf("%p\n", (void* )main); return 0; } $ gcc -ansi -pedantic -Wall test.c -o test test.c: In function 'main': test.c:6: warning: ISO C forbids conversion of function pointer to object pointer type test.c:7: warning: ISO C forbids conversion of function pointer to object pointer type $ ./test 0x400518 0x400518 It's "working", but non-standard...

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  • LINQ-to-SQL Query Timing Out

    - by kevinw
    I'm running this query in LINQ: var unalloc = db.slot_sp_getUnallocatedJobs("Repair", RadComboBox1.SelectedValue, 20); It runs when I first open the page, but when I go back to it and try to run the same query with a different value, "Con", being passed through, the linq to sql designer.cs tells me that I've got a timeout error. Any ideas? Edit: This is what's in the designer: [Function(Name="dbo.slot_sp_getUnallocatedJobs")] Public ISingleResult<slot_sp_getUnallocatedJobsResult> slot_sp_getUnallocatedJobs([Parameter(Name="JobType", DbType="VarChar(20)")] string jobType, [Parameter(Name="Contract", DbType="VarChar(10)")] string contract, [Parameter(Name="Num", DbType="Int")] System.Nullable<int> num) { IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), jobType, contract, num); return ((ISingleResult<slot_sp_getUnallocatedJobsResult>)(result.ReturnValue)); } } This is the error: SQLException was unhandled by user code Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

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  • function parameter used to store value

    - by user248247
    Hi, I have to define an interface. The API in my homework is stated below: int generate_codes(char * ssn, char * student_id); int denotes 0 or 1 for pass or fail. studentid is an output param should return a 6 digit id. ssn is a 9 digit input param they school program will take ssn's and use my code to generate the student id. now from an API perspective should I not be using const char * for both parameters. should the studentid not be passed in by reference? rather than by pointer? can someone tell me how i can easily use the pointer in my test app which uses my api to get the pointer such that it prints a std::string from a char *? my app code looks something like const char * ssn = "987098765" const char * studnt_id = new char [7]; int value = -1; value = generate_codes(ssn,studnt_id); std::string test(studnt_id); std::cout<<"student id= "<<test<<" Pass/fail= "<<value<<std::endl; delete [] studnt_id; return 0; I basically got an error about << not being compatible with the right hand side of the operand. When i changed the code to std::cout<<"student id= "<<test.c_str()<<" Pass/fail= "<<value<<std::endl; then it worked but i get garbage for the value. not sure how to do get the value form the pointer. THe value inside the function prints just fine. but when i try to print it outside of the function it prints garbage. Inside the above function I do set the studndt_id like so std::string str_studnt_id = studnt_id; should that make the address of the str_studnt point to the address of studnt_id and thus any changes I make to the value that its pointing to it should reflect outside the function?

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  • compiler warning at C++ template base class

    - by eike
    I get a compiler warning, that I don't understand in that context, when I compile the "Child.cpp" from the following code. (Don't wonder: I stripped off my class declarations to the bare minuum, so the content will not make much sense, but you will see the problem quicker). I get the warning with VS2003 and VS2008 on the highest warning level. The code AbstractClass.h : #include <iostream> template<typename T> class AbstractClass { public: virtual void Cancel(); // { std::cout << "Abstract Cancel" << std::endl; }; virtual void Process() = 0; }; //outside definition. if I comment out this and take the inline //definition like above (currently commented out), I don't get //a compiler warning template<typename T> void AbstractClass<T>::Cancel() { std::cout << "Abstract Cancel" << std::endl; } Child.h : #include "AbstractClass.h" class Child : public AbstractClass<int> { public: virtual void Process(); }; Child.cpp : #include "Child.h" #include <iostream> void Child::Process() { std::cout << "Process" << std::endl; } The warning The class "Child" is derived from "AbstractClass". In "AbstractClass" there's the public method "AbstractClass::Cancel()". If I define the method outside of the class body (like in the code you see), I get the compiler warning... AbstractClass.h(7) : warning C4505: 'AbstractClass::Cancel' : unreferenced local function has been removed with [T=int] ...when I compile "Child.cpp". I do not understand this, because this is a public function and the compiler can't know if I later reference this method or not. And, in the end, I reference this method, because I call it in main.cpp and despite this compiler warning, this method works if I compile and link all files and execute the program: //main.cpp #include <iostream> #include "Child.h" int main() { Child child; child.Cancel(); //works, despite the warning } If I do define the Cancel() function as inline (you see it as out commented code in AbstractClass.h), then I don't get the compiler warning. Of course my program works, but I want to understand this warning or is this just a compiler mistake? Furthermore, if do not implement AbsctractClass as a template class (just for a test purpose in this case) I also don't get the compiler warning...?

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  • Why C# calls different overloaded method for different values of same type?

    - by Fabio Veronez
    Hello all, I have one doubt concerning c# method overloading call resolution. Let's suppose I have the following C# code: enum MyEnum { Value1, Value2 } public void test() { method(0); // this calls method(MyEnum) method(1); // this calls method(object) } public void method(object o) { } public void method(MyEnum e) { } Note that I know how to make it work but I would like to know why for one value of int (0) it calls one method and for another (1) it calls another. It sounds awkward since both values have the same type (int) but they are "linked" for different methods. Ps.: This is my first question here, i'm sorry if I made something wrong. =P

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  • What is the proper way to create a recursive entity in the Entity Framework?

    - by Orion Adrian
    I'm currently using VS 2010 RC, and I'm trying to create a model that contains a recursive self-referencing entity. Currently when I import the entity from the model I get an error indicating that the parent property cannot be part of the association because it's set to 'Computed' or 'Identity', though I'm not sure why it does it that way. I've been hand-editing the file to get around that error, but then the model simply doesn't work. What is the proper way to get recursive entities to work in the Entity Framework. CREATE TABLE [dbo].[Appointments]( [AppointmentId] [int] IDENTITY(1,1) NOT NULL, [Description] [nvarchar](1024) NULL, [Start] [datetime] NOT NULL, [End] [datetime] NOT NULL, [Username] [varchar](50) NOT NULL, [RecurrenceRule] [nvarchar](1024) NULL, [RecurrenceState] [varchar](20) NULL, [RecurrenceParentId] [int] NULL, [Annotations] [nvarchar](50) NULL, [Application] [nvarchar](100) NOT NULL, CONSTRAINT [PK_Appointments] PRIMARY KEY CLUSTERED ( [AppointmentId] ASC ) ) GO ALTER TABLE [dbo].[Appointments] WITH CHECK ADD CONSTRAINT [FK_Appointments_ParentAppointments] FOREIGN KEY([RecurrenceParentId]) REFERENCES [dbo].[Appointments] ([AppointmentId]) GO ALTER TABLE [dbo].[Appointments] CHECK CONSTRAINT [FK_Appointments_ParentAppointments] GO

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  • how to use a tree data structure in C#

    - by matti
    I found an implementation for a tree at this SO question. Unfortunately I don't know how to use it. Also I made a change to it since LinkedList does not have Add method: delegate void TreeVisitor<T>(T nodeData); class NTree<T> { T data; List<NTree<T>> children; public NTree(T data) { this.data = data; children = new List<NTree<T>>(); } public void AddChild(T data) { children.Add(new NTree<T>(data)); } public NTree<T> GetChild(int i) { return children[i]; } public void Traverse(NTree<T> node, TreeVisitor<T> visitor) { visitor(node.data); foreach (NTree<T> kid in node.children) Traverse(kid, visitor); } } I have class named tTable and I want to store it's children and their grandchildren (...) in this tree. My need is to find immediate children and not traverse entire tree. I also might need to find children with some criteria. Let's say tTable has only name and I want to find children with names matching some criteria. tTables constructor gives name a value according to int-value (somehow). How do I use Traverse (write delegate) if I have code like this; int i = 0; Dictionary<string, NTree<tTable>> tableTreeByRootTableName = new Dictionary<string, NTree<tTable>>(); tTable aTable = new tTable(i++); tableTreeByRootTableName[aTable.Name] = new NTree(aTable); tableTreeByRootTableName[aTable.Name].AddChild(new tTable(i++)); tableTreeByRootTableName[aTable.Name].AddChild(new tTable(i++)); tableTreeByRootTableName[aTable.Name].GetChild(1).AddChild(new tTable(i++));

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  • "is not abstact and does not override abstract method."

    - by Chris Bolton
    So I'm pretty new to android development and have been trying to piece together some code bits. Here's what I have so far: package com.teslaprime.prirt; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.AdapterView.OnItemClickListener; import java.util.ArrayList; import java.util.List; public class TaskList extends Activity { List<Task> model = new ArrayList<Task>(); ArrayAdapter<Task> adapter = null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button add = (Button) findViewById(R.id.add); add.setOnClickListener(onAdd); ListView list = (ListView) findViewById(R.id.tasks); adapter = new ArrayAdapter<Task>(this,android.R.layout.simple_list_item_1,model); list.setAdapter(adapter); list.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(View v, int position, long id) { adapter.remove(position); } });} private View.OnClickListener onAdd = new View.OnClickListener() { public void onClick(View v) { Task task = new Task(); EditText name = (EditText) findViewById(R.id.taskEntry); task.name = name.getText().toString(); adapter.add(task); } }; } and here are the errors I'm getting: compile: [javac] /opt/android-sdk/tools/ant/main_rules.xml:384: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds [javac] Compiling 2 source files to /home/chris-kun/code/priRT/bin/classes [javac] /home/chris-kun/code/priRT/src/com/teslaprime/prirt/TaskList.java:30: <anonymous com.teslaprime.prirt.TaskList$1> is not abstract and does not override abstract method onItemClick(android.widget.AdapterView<?>,android.view.View,int,long) in android.widget.AdapterView.OnItemClickListener [javac] list.setOnItemClickListener(new OnItemClickListener() { [javac] ^ [javac] /home/chris-kun/code/priRT/src/com/teslaprime/prirt/TaskList.java:32: remove(com.teslaprime.prirt.Task) in android.widget.ArrayAdapter<com.teslaprime.prirt.Task> cannot be applied to (int) [javac] adapter.remove(position); [javac] ^ [javac] 2 errors BUILD FAILED /opt/android-sdk/tools/ant/main_rules.xml:384: Compile failed; see the compiler error output for details. Total time: 2 seconds any ideas?

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  • GDB hardware watchpoint very slow - why?

    - by Laurynas Biveinis
    On a large C application, I have set a hardware watchpoint on a memory address as follows: (gdb) watch *((int*)0x12F5D58) Hardware watchpoint 3: *((int*)0x12F5D58) As you can see, it's a hardware watchpoint, not software, which would explain the slowness. Now the application running time under debugger has changed from less than ten seconds to one hour and counting. The watchpoint has triggered three times so far, the first time after 15 minutes when the memory page containing the address was made readable by sbrk. Surely during those 15 minutes the watchpoint should have been efficient since the memory page was inaccessible? And that still does not explain, why it's so slow afterwards. The GDB is $ gdb --version GNU gdb (GDB) 7.0-ubuntu [...] Thanks in advance for any ideas as what might be the cause or how to fix/work around it.

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  • What does subl do here?

    - by drozzy
    So... I'm compiling into assembler, with gcc -S -O2 -m32: void h(int y){int x; x=y+1; f(y); f(2); } And it gives me the following: .file "sample.c" .text .p2align 4,,15 .globl h .type h, @function h: pushl %ebp movl %esp, %ebp subl $24, %esp movl 8(%ebp), %eax movl %eax, (%esp) call f movl $2, 8(%ebp) leave jmp f .size h, .-h .ident "GCC: (GNU) 4.4.3 20100127 (Red Hat 4.4.3-4)" .section .note.GNU-stack,"",@progbits Now I know what pushl and movel: they store the current frame pointer onto the stack and then set the value of the frame pointer register to the value of the Stack Pointer. But I have no idea what the subl $24, %esp is. Thanks!

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  • improving conversions to binary and back in C#

    - by Saad Imran.
    I'm trying to write a general purpose socket server for a game I'm working on. I know I could very well use already built servers like SmartFox and Photon, but I wan't to go through the pain of creating one myself for learning purposes. I've come up with a BSON inspired protocol to convert the the basic data types, their arrays, and a special GSObject to binary and arrange them in a way so that it can be put back together into object form on the client end. At the core, the conversion methods utilize the .Net BitConverter class to convert the basic data types to binary. Anyways, the problem is performance, if I loop 50,000 times and convert my GSObject to binary each time it takes about 5500ms (the resulting byte[] is just 192 bytes per conversion). I think think this would be way too slow for an MMO that sends 5-10 position updates per second with a 1000 concurrent users. Yes, I know it's unlikely that a game will have a 1000 users on at the same time, but like I said earlier this is supposed to be a learning process for me, I want to go out of my way and build something that scales well and can handle at least a few thousand users. So yea, if anyone's aware of other conversion techniques or sees where I'm loosing performance I would appreciate the help. GSBitConverter.cs This is the main conversion class, it adds extension methods to main datatypes to convert to the binary format. It uses the BitConverter class to convert the base types. I've shown only the code to convert integer and integer arrays, but the rest of the method are pretty much replicas of those two, they just overload the type. public static class GSBitConverter { public static byte[] ToGSBinary(this short value) { return BitConverter.GetBytes(value); } public static byte[] ToGSBinary(this IEnumerable<short> value) { List<byte> bytes = new List<byte>(); short length = (short)value.Count(); bytes.AddRange(length.ToGSBinary()); for (int i = 0; i < length; i++) bytes.AddRange(value.ElementAt(i).ToGSBinary()); return bytes.ToArray(); } public static byte[] ToGSBinary(this bool value); public static byte[] ToGSBinary(this IEnumerable<bool> value); public static byte[] ToGSBinary(this IEnumerable<byte> value); public static byte[] ToGSBinary(this int value); public static byte[] ToGSBinary(this IEnumerable<int> value); public static byte[] ToGSBinary(this long value); public static byte[] ToGSBinary(this IEnumerable<long> value); public static byte[] ToGSBinary(this float value); public static byte[] ToGSBinary(this IEnumerable<float> value); public static byte[] ToGSBinary(this double value); public static byte[] ToGSBinary(this IEnumerable<double> value); public static byte[] ToGSBinary(this string value); public static byte[] ToGSBinary(this IEnumerable<string> value); public static string GetHexDump(this IEnumerable<byte> value); } Program.cs Here's the the object that I'm converting to binary in a loop. class Program { static void Main(string[] args) { GSObject obj = new GSObject(); obj.AttachShort("smallInt", 15); obj.AttachInt("medInt", 120700); obj.AttachLong("bigInt", 10900800700); obj.AttachDouble("doubleVal", Math.PI); obj.AttachStringArray("muppetNames", new string[] { "Kermit", "Fozzy", "Piggy", "Animal", "Gonzo" }); GSObject apple = new GSObject(); apple.AttachString("name", "Apple"); apple.AttachString("color", "red"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.5); GSObject lemon = new GSObject(); apple.AttachString("name", "Lemon"); apple.AttachString("color", "yellow"); apple.AttachBool("inStock", false); apple.AttachFloat("price", (float)0.8); GSObject apricoat = new GSObject(); apple.AttachString("name", "Apricoat"); apple.AttachString("color", "orange"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.9); GSObject kiwi = new GSObject(); apple.AttachString("name", "Kiwi"); apple.AttachString("color", "green"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)2.3); GSArray fruits = new GSArray(); fruits.AddGSObject(apple); fruits.AddGSObject(lemon); fruits.AddGSObject(apricoat); fruits.AddGSObject(kiwi); obj.AttachGSArray("fruits", fruits); Stopwatch w1 = Stopwatch.StartNew(); for (int i = 0; i < 50000; i++) { byte[] b = obj.ToGSBinary(); } w1.Stop(); Console.WriteLine(BitConverter.IsLittleEndian ? "Little Endian" : "Big Endian"); Console.WriteLine(w1.ElapsedMilliseconds + "ms"); } Here's the code for some of my other classes that are used in the code above. Most of it is repetitive. GSObject GSArray GSWrappedObject

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  • Can someone explain this "endian-ness" function for me?

    - by Mike
    Write a program to determine whether a computer is big-endian or little-endian. bool endianness() { int i = 1; char *ptr; ptr = (char*) &i; return (*ptr); } So I have the above function. I don't really get it. ptr = (char*) &i, which I think means a pointer to a character at address of where i is sitting, so if an int is 4 bytes, say ABCD, are we talking about A or D when you call char* on that? and why? Would some one please explain this in more detail? Thanks. So specifically, ptr = (char*) &i; when you cast it to char*, what part of &i do I get?

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  • Write subquery in Criteria of nHibernate.

    - by Bipul
    I read about subquery in Criteria, but I am still unable to grasp it properly. So, here I am taking one example and if somebody can help me writing that using subquery it will be great. Lets say we have table Employee{EmployeeId.(int),Name(string),Post(string),No_Of_years_working(int)} Now I want all the employees who are Managers and working for less than 10 years. I know that we can get the result without using subqueries but I wanna use subquery just to understand how it works in criteria. So, how I can write Criteria using subquery to get those employees. Thanks

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