Search Results

Search found 43645 results on 1746 pages for 'student question'.

Page 80/1746 | < Previous Page | 76 77 78 79 80 81 82 83 84 85 86 87  | Next Page >

  • Singleton constructor question

    - by gillyb
    Hi, I created a Singleton class in c#, with a public property that I want to initialize when the Singleton is first called. This is the code I wrote : public class BL { private ISessionFactory _sessionFactory; public ISessionFactory SessionFactory { get { return _sessionFactory; } set { _sessionFactory = value; } } private BL() { SessionFactory = Dal.SessionFactory.CreateSessionFactory(); } private object thisLock = new object(); private BL _instance = null; public BL Instance { get { lock (thisLock) { if (_instance == null) { _instance = new BL(); } return _instance; } } } } As far as I know, when I address the Instance BL object in the BL class for the first time, it should load the constructor and that should initialize the SessionFactory object. But when I try : BL.Instance.SessionFactory.OpenSession(); I get a Null Reference Exception, and I see that SessionFactory is null... why?

    Read the article

  • question bitonic sequence

    - by davit-datuashvili
    A sequence is bitonic if it monotonically increases and then monotonically de- creases, or if it can be circularly shifted to monotonically increase and then monotonically decrease. For example the sequences 1, 4, 6, 8, 3, -2 , 9, 2, -4, -10, -5 , and 1, 2, 3, 4 are bitonic, but 1, 3, 12, 4, 2, 10 is not bitonic. please help me to determine if given sequence is bitonic?

    Read the article

  • Python decorator question

    - by nsharish
    decorator 1: def dec(f): def wrap(obj, *args, **kwargs): f(obj, *args,**kwargs) return wrap decorator 2: class dec: def __init__(self, f): self.f = f def __call__(self, obj, *args, **kwargs): self.f(obj, *args, **kwargs) A sample class, class Test: @dec def disp(self, *args, **kwargs): print(*args,**kwargs) The follwing code works with decorator 1 but not with decorator 2. a = Test() a.disp("Message") I dont understand why decorator 2 is not working here. Can someone help me with this?

    Read the article

  • postgreSQL - pg_class question

    - by Sachin Chourasiya
    PostgreSQL stores statistics about tables in the system table called pg_class. The query planner accesses this table for every query. These statistics may only be updated using the analyze command. If the analyze command is not run often, the statistics in this table may not be accurate and the query planner may make poor decisions which can degrade system performance. Another strategy is for the query planner to generate these statistics for each query (including selects, inserts, updates, and deletes). This approach would allow the query planner to have the most up-to-date statistics possible. Why postgres always rely on pg_class instead?

    Read the article

  • SQL CASE Question

    - by docsql
    Hiya, I dont know if this can be done but i'd though i'd ask. What I want to do is have a case statement query and if a 1 begin another action. if 0 dont do anything. For Example select CASE WHEN client.deathofdeath = yes THEN 1 do another select in here (which is another table) Else 0 End AS DeathDate From Client client Can this be done?

    Read the article

  • Odd C interview question

    - by Brennan Vincent
    Hi guys. I found this problem on a site full of interview questions, and was stumped by it. Is there some preprocessor directive that allows one to read from standard input during compilation? Write a small C program, which while compiling takes another program from input terminal, and on running gives the result for the second program. (NOTE: The key is, think UNIX). Suppose, the program is 1.c Then, while compiling $ cc -o 1 1.c int main() { printf("Hello World\n"); } ^D $ ./1 Hello World

    Read the article

  • C question on functions

    - by benjamin button
    some times i see that functions are defined as below: read_dir(dir) char *dir; { DIR * dirp; struct dirent *d; /* open directory */ dirp = opendir(dir); ......... so on here what is the importance of the statement char *dir; what is the intension behind declaring the pointer soon after the function name and then starting the function body.

    Read the article

  • Python meta programming question

    - by orokusaki
    I have a meta class MyClass which adds an attribute to a class based on some of the properties of the class's methods. When I subclass MyClass I want it to still have that attribute, and append to the attribute's value based on the sub-class's methods (ie, sub-classing extends the same attribute that the base's meta creates.). Can this be done via the bases argument passed to __new__(cls, name, bases, dct)?

    Read the article

  • Question about joins and table with Millions of rows

    - by xRobot
    I have to create 2 tables: Magazine ( 10 millions of rows with these columns: id, title, genres, printing, price ) Author ( 180 millions of rows with these columns: id, name, magazine_id ) . Every author can write on ONLY ONE magazine and every magazine has more authors. So if I want to know all authors of Motors Magazine, I have to use this query: SELECT * FROM Author, Magazine WHERE ( Author.id = Magazine.id ) AND ( genres = 'Motors' ) The same applies to Printing and Price column. To avoid these joins with tables of millions of rows, I thought to use this tables: Magazine ( 10 millions of rows with this column: id, title, genres, printing, price ) Author ( 180 millions of rows with this column: id, name, magazine_id, genres, printing, price ) . and this query: SELECT * FROM Author WHERE genres = 'Motors' Is it a good approach ? I can use Postgresql or Mysql.

    Read the article

  • Mysql regexp performance question

    - by Tim
    Rumour has it that this; SELECT * FROM lineage_string where lineage like '%179%' and lineage regexp '(^|/)179(/|$)' Would be faster than this; SELECT * FROM lineage_string where lineage regexp '(^|/)179(/|$)' Can anyone confirm ? Or know a decent way to test the speed of such queries. Thanks

    Read the article

  • javascript and extJs - scope question

    - by ben
    Hi guys, I got a little scope related problem with some js code, maybe somebody can explain to me what I'm making wrong: I'm using extJs and got this snippet: Ext.onReady(function(){ // Form for filter selection var formFilter = new Ext.FormPanel({ // ... items: [ cbGroup = new Ext.form.ComboBox({ fieldLabel: 'Group', store: dsGroups, displayField: 'name', valueField: 'number', emptyText : '- Please choose a group -', listeners:{ 'select': function() { alert(cbGroup.selectedIndex +' '+this.selectedIndex); } } }) ] }); }); The problem: When I access the combobox over 'this' within the listener function, I get the correct result for the selectIndex property. When I access the combobox over it's var name, I allways get the result '-1'. Thank a lot for your help!

    Read the article

  • XNA Vector2 Rotation Question

    - by Tom Allen
    I'm messing about with some stuff in XNA and am trying to move an object around asteroids-style in that you press left and right to rotate and up/down to go forwards and backwards in the direction you are pointing. I've got the rotation of the sprite done, but i can't get the object to move in the direction you've pointed it, it always moves up and down on the x = 0 axis. I'm guessing this is straight forward but I just can't figure it out. My "ship" class has the following properties which are note worthy here: Vector2 Position float Rotation The "ship" class has an update method is where the input is handled and so far I've got the following: public void Update(GameTime gameTime) { KeyboardState keyboard = Keyboard.GetState(); GamePadState gamePad = GamePad.GetState(PlayerIndex.One); float x = Position.X; float y = Position.Y; if (keyboard.IsKeyDown(Keys.Left)) Rotation -= 0.1f; if (keyboard.IsKeyDown(Keys.Right)) Rotation += 0.1f; if (keyboard.IsKeyDown(Keys.Up)) y -= ??; if (keyboard.IsKeyDown(Keys.Down)) y += ??; this.Position = new Vector2(x, y); } Any help would be most appreciated!

    Read the article

  • Motherboard memory question

    - by JERiv
    I am currently drawing up specs on a new workstation for my office. I am considering the Asus P6X58D for a motherboard. This board's specs list it as supporting 24 gigs of memory. Suppose I were to use six four gig memory cards and then two video cards with 1 gig of memory apiece. Is the maximum supported memory similar to how 32 bit operating systems only have enough address space for 4 gigs of memory? Simply: Will the board post? If so, will the system be able to address all the memory, both the 24 gigs on the ddr3 bus and the 3 gigs on the graphics card?

    Read the article

  • jquery javascript question

    - by mckenzie
    Hello, var val = $("#desc").val(); // input box var val2 = $("#type").val(); // select box if((val=='') || (val2 == '')) { alert("err"); } else { // codes } when i select dropdown and not type anything on inputbox, the alert err still comes out? how to make it when dropdown is selected, it goes to else clause?

    Read the article

  • Simple question about C++ constant syntax

    - by WilliamLou
    Here is some code copied from Thinking in C++ Vol1 Chapter 10. #include <iostream> using namespace std; int x = 100; class WithStatic { static int x; static int y; public: void print() const { cout << "WithStatic::x = " << x << endl; cout << "WithStatic::y = " << y << endl; } }; what's the meaning of const for the function print()? Thanks!

    Read the article

  • StructureMap Question

    - by derans
    This is the equivalent of what I'm trying to create with StructureMap: new ChangePasswordWithNotificationAndLoggingService( new ChangePasswordService( new ActiveDirectoryRepository(new ActiveDirectoryCredentials()), new TokenRepository("")), new EmailNotificationService(new PasswordChangedNotification(new UserAccount())), new LoggingService()); This is what I have right now: ForRequestedType<IChangePasswordService>() .TheDefault.Is.ConstructedBy(() => new ChangePasswordService(DependencyRegistrar.Resolve<IActiveDirectoryRepository>(), DependencyRegistrar.Resolve<ITokenRepository>())) .EnrichWith<IChangePasswordService>(x => new ChangePasswordWithNotificationAndLoggingService(x, DependencyRegistrar.Resolve<INotificationService>(), DependencyRegistrar.Resolve<ILoggingService>())); I need to pass the UserAccount to the INotificationService...can't figure it out. I've tried this: DependencyRegistrar.With(new UserAccount { Username = "test" }); No luck...UserAccount always turns out null. I don't have to do it all with StructureMap, I'm open to any suggestions. This is what I currently have working: public static IChangePasswordService ChangePasswordService(UserAccount userAccount) { return new ChangePasswordWithNotificationService( new ChangePasswordService(ActiveDirectoryRepository(), TokenRepository()), new EmailNotificationService(new PasswordChangedNotification(userAccount))); }

    Read the article

  • Jquery selectors question

    - by Ben
    Hi all, I am not an expert at jquery but trying to get a menu to work. Basically, I have a menu made of up to 3 levels of nested lists. The first level has a little arrow has a background image that opens or close when opening the first level list. Any other nested lists don't need to have the background image. My script opens the menu when you click on it and is also supposed to switch the first level list from a class "inactive" to a class "active". Here is the script: $(document).ready(function(){ $("#left-navigation-holder ul.level1 li.inactive").toggle(function(){ $(this).addClass("active"); }, function () { $(this).removeClass("active"); }); $("#left-navigation-holder li a").click(function(){ menu = $(this).parent('li').children('ul'); menu.toggle(); }); }); The problem is that the toggle function also happens when clicking on second and third level lists causing the arrows to toggle even if the first level list isn't clicked on. I thought using $("#left-navigation-holder ul.level1 li.inactive").toggle would limit the function to the first level list with a class "inactive". Any help would be really appreciated. Ben

    Read the article

  • Noob Droid Question regarding random number

    - by Pete Herbert Penito
    Brand new to droid programming, but would love to learn as much as possible, so I finally got my emulator working correctly, I even got a hello world button to work, I'm attempting to make this button display a random number, I've googled this and came up with this code: Random generator = new Random(); int n = generator.nextInt(n); I fixed the Random function by including some Random java utility. I'm assuming this code above goes in the .java file of the project, so my button code looks as follows (tested and works): PopUpText.makeText(v.getContext(), "Hello World", PopUpText.LENGTH_LONG).show(); I figured I could replace "Hello World" with n to display the number in the box, however the following error is stopping the compile: The local variable n may not have been initialized Any ideas why this is happening? Any advice would be hugely appreciated.

    Read the article

  • Question of using static_cast on "this" pointer in a derived object to base class

    - by Johnyy
    Hi, this is an example taken from Effective C++ 3ed, it says that if the static_cast is used this way, the base part of the object is copied, and the call is invoked from that part. I wanted to understand what is happening under the hood, will anyone help? class Window { // base class public: virtual void onResize() { } // base onResize impl }; class SpecialWindow: public Window { // derived class public: virtual void onResize() { // derived onResize impl; static_cast<Window>(*this).onResize(); // cast *this to Window, // then call its onResize; // this doesn't work! // do SpecialWindow- } // specific stuff };

    Read the article

  • Solr security question

    - by Camran
    I have a linux server, and I am about to upload a classifieds website to it. The website is php based. That means php code adds/removes classifieds, with the help of the users offcourse. The php-code then adds/removes a classified to a database index called Solr (like MySql). Problem is that anybody can currently access the database, but I only want the website to access the database (solr). Solr is on port 8983 as standard btw. My Q is, if I add a rule in my firewall (iptables), to only allow connections coming from the servers IP to the Solr port nr, would this solve my issue? Thanks

    Read the article

  • Google street view URL question:

    - by Rhythmic Algorithm
    Hi I have the address of a property and my application can launch a browser to go to http://maps.google.com?q=searchStringHere. If a good match is found it will take it directly there. Is there any thing I can append to the url to make it switch to streetview without having the exact coordinates? I dont't want to code any javascript or flash.

    Read the article

< Previous Page | 76 77 78 79 80 81 82 83 84 85 86 87  | Next Page >