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• Linq2SQL or EntityFramework and databinding

  - by rene marxis

  is there some way to do databinding with linq2SQL or EntityFramework using "typed links" to the bound property? Public Class Form1 Dim db As New MESDBEntities 'datacontext/ObjectContext Dim bs As New BindingSource Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load bs.DataSource = (From m In db.PROB_GROUP Select m) grid.DataSource = bs TextBox1.DataBindings.Add("Text", bs, "PGR_NAME") TextBox1.DataBindings.Add("Text", bs, db.PROB_GROUP) '**<--- Somthing like this** End Sub End Class I'd like to have type checking when compiling and the model changed.

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• Why does this compile?

  - by akf

  I was taken aback earlier today when debugging some code to find that something like the following does not throw a compile-time exception: public Test () { HashMap map = (HashMap) getList(); } private List getList(){ return new ArrayList(); } As you can imagine, a ClassCastException is thrown at runtime, but can someone explain why the casting of a List to a HashMap is considered legal at compile time?

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• Unnecessary code...

  - by Martin Milan

  Suppose I have some code that looks like this: Private Sub MySub() dim blnFlag as Boolean blnFlag = False for each item in collection if item.Name = "Mike" then blnFound = true exit for endif next item End Sub Now - the blnFLag = False assignment is not actually necessary - booleans are initialised as false, but I think it's inclusion makes the code easier to read. What's your opinion?

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• callback function for php preg_replace_callback not getting called on linux CentOS 5.4

  - by user105165

  I have used the preg_replace_callback as $string = preg_replace_callback($pattern,'CreateTemplatesController::callbackhandler',$string ); I have called the callbackhandler function with the class name as this function is a private static function. Problem is "callbackhandler" function is not getting called. Please post if any one know the reason for the same. Thanks in Advance

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• Transparent textbox when textbox GotFocussed Windows Phone 8.1?

  - by user3701923

  I need to have transparent textbox, in my WindowsPhone 8.1 Runtime application. I made Background="Transparent" to the textbox, so it is transparent when it is loaded. But on focus, background color changed to white. I write the following code, to make it transparent. But it doesn't run.! <TextBox Background="Transparent" GotFocus="titleBox_GotFocus" /> C# private void titleBox_GotFocus(object sender, RoutedEventArgs e) { titleBox.Background = new SolidColorBrush(Colors.Transparent); }

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• C# if no error contiune.. if error occurse do else

  - by NightsEVil

  hi i have a question i have some code that works good on like 70% of the computers i use it on but.. for some reason theres a few that are pesky and id like to do something like this (keep in mind this is a hypothetical) private void test_click(object sender, EventArgs e) { MessageBox.Show("hi"); //if it works ok without a error it continues to MessageBox.Show("worked ok"); //if it encountered a error of some kind it would go to MessageBox.Show("DID NOT WORK OK"); }

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• textbox accept only digits

  - by hiba salem

  Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress Dim allowedChars As String = "0123456789$," If allowedChars.IndexOf(e.KeyChar) = -1 Then ' Invalid Character e.Handled = True End If End Sub this code accept only digits and its working like a charm but if i typed a wrong number its not allowing me to use the delete or the backspace on the keyboard how to solve this problem ?

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• Suggestions In Porting ASP.NET to MVC.NET - Is storing SiteConfiguration in Cache RESTful?

  - by DaveDev

  I've been tasked with porting/refactoring a Web Application Platform that we have from ASP.NET to MVC.NET. Ideally I could use all the existing platform's configurations to determine the properties of the site that is presented. Is it RESTful to keep a SiteConfiguration object which contains all of our various page configuration data in the System.Web.Caching.Cache? There are a lot of settings that need to be loaded when the user acceses our site so it's inefficient for each user to have to load the same settings every time they access. Some data the SiteConfiguration object contains is as follows and it determines what Master Page / site configuration / style / UserControls are available to the client, public string SiteTheme { get; set; } public string Region { private get; set; } public string DateFormat { get; set; } public string NumberFormat { get; set; } public int WrapperType { private get; set; } public string LabelFileName { get; set; } public LabelFile LabelFile { get; set; } // the following two are the heavy ones // PageConfiguration contains lots of configuration data for each panel on the page public IList<PageConfiguration> Pages { get; set; } // This contains all the configurations for the factsheets we produce public List<ConfiguredFactsheet> ConfiguredFactsheets { get; set; } I was thinking of having a URL structure like this: www.MySite1.com/PageTemplate/UserControl/ the domain determines the SiteConfiguration object that is created, where MySite1.com is SiteId = 1, MySite2.com is SiteId = 2. (and in turn, style, configurations for various pages, etc.) PageTemplate is the View that will be rendered and simply defines a layout for where I'm going to inject the UserControls Can somebody please tell me if I'm completely missing the RESTful point here? I'd like to refactor the platform into MVC because it's better to work in but I want to do it right but with a minimum of reinventing-the-wheel because otherwise it won't get approval. Any suggestions otherwise? Thanks

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• Do you use logical negation operator (!) in "if" statement or check on "== false"

  - by Taras Terebkov

  Hello everyone, I just want to conduct a little survey about code style developers prefer. For me there are two ways to write "if" in such languages as Java, C#, C++, etc. (1) Logical negation operator public void foo() { if (!SessionManager.getInstance().hasActiveSession()) { . . . . . } } (2) Check on "false" public void foo() { if (SessionManager.getInstance().hasActiveSession() == false) { . . . . . } } I always believe that first way is much worst then the second one. Cause usually you don't "read" the code, but "recognize" it in one brief look. And exclamation symbol slipped from your mind, just disturbing you somewhere on the bottom of your unconscious. And only during reading the "if" block below you understand, that the logic is opposite - no sessions in "if" On the other hand in the second way of writing, an eye immediately catches words "SessionManager", "hasActiveSession" and "false". Also for me, the situation with "true" is different. In code like class SessionManager { private bool hasSession; public void foo() { if (hasSession == true) { . . . . . } else { . . . . . } } } I find "true" superfluous. why we repeating the sentence two times? The following is shorter and quicker to catch. class SessionManager { private bool hasSession; public void foo() { if (hasSession) { . . . . . } else { . . . . . } } } What do YOU think, guys?

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• Does binding temporary to a reference require a copy constructor in C++?

  - by vitaut

  Consider the following code: class A { A(const A&); public: A() {} }; int main() { const A &a = A(); } This code compiles fine with GCC, but fails to compile with Visual C++ with the following error: test.cc(8) : error C2248: 'A::A' : cannot access private member declared in class 'A' test.cc(2) : see declaration of 'A::A' test.cc(1) : see declaration of 'A' So is it necessary to have a copy constructor accessible when binding a temporary to a reference?

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• @Resource annotation is null at run-time.

  - by Andrew

  I'm using GlassFish v3. The following field is declared in a class: @Resource private javax.sql.DataSource _data_source; The following is declare in web.xml: <data-source <namejava:app/env/data</name <class-namecom.mysql.jdbc.Driver</class-name <server-namelocalhost</server-name <port-number3306</port-number <usermyUser</user <passwordmyPass</password </data-source At run-time _data_source is empty. What am I doing wrong?

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• mouse event on picturebox

  - by user548694

  I want to see my pixel coordinates on moviing my mouse on the image in picture box I have added this event Form.designer.cs this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseDown); and this method in Form.cs private void pictureBox1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) { locationtxt.Text = e.X.ToString() + "," + e.Y.ToString(); } but I cann't see anything in textbox on moving my mouse on form runtime. What should i add further. regards,

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• @Unique doesn't have any effect in DataNucleus w/ NeoDatis

  - by David Parks

  Using JDO / DataNucleus / NeoDatis datastore I added @Unique to a field of a persistable object, however I am allowed to create multiple objects which violate the unique constraint. The docs for DataNucleus/NeoDatis suggest that Unique fields are supported. @PersistenceCapable public class User { @Persistent @Unique private String username; //... } If I add multiple objects to the DB with the same username there's no problem doing so. :(

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• Populating data in multiple cascading dropdown boxes in Access 2007

  - by miCRoSCoPiC_eaRthLinG

  Hello all, I've been assigned the task to design a temporary customer tracking system in MS Access 2007 (sheeeesh!). The tables and relationships have all been setup successfully. But I'm running into a minor problem while trying to design the data entry form for one table... Here's a bit of explanation first. The screen contains 3 dropdown boxes (apart from other fields). 1st dropdown The first dropdown (cboMarket) represents the Market lets users select between 2 options: Domestic International Since the first dropdown contains only 2 items I didn't bother making a table for it. I added them as pre-defined list items. 2nd dropdown Once the user makes a selection in this one, the second dropdown (cboLeadCategory) loads up a list of Lead Categories, namely, Fairs & Exhibitions, Agents, Press Ads, Online Ads etc. Different sets of lead categories are utilized for the 2 markets. Hence this box is dependent on the 1st one. Structure of the bound table, named Lead_Cateogries for the 2nd combo is: ID Autonumber Lead_Type TEXT <- actually a list that takes up Domestic or International Lead_Category_Name TEXT 3rd dropdown And based on the choice of category in the 2nd one, the third one (cboLeadSource) is supposed to display a pre-defined set of lead sources belonging to the particular category. Table is named Lead_Sources and the structure is: ID Autonumber Lead_Category NUMBER <- related to ID of Lead Categories table Lead_Source TEXT When I make the selection in the 1st dropdown, the AfterUpdate event of the combo is called, which instructs the 2nd dropdown to load contents: Private Sub cboMarket_AfterUpdate() Me![cboLead_Category].Requery End Sub The Row Source of the 2nd combo contains a query: SELECT Lead_Categories.ID, Lead_Categories.Lead_Category_Name FROM Lead_Categories WHERE Lead_Categories.Lead_Type=[cboMarket] ORDER BY Lead_Categories.Lead_Category_Name; The AfterUpdate event of 2nd combo is: Private Sub cboLeadCategory_AfterUpdate() Me![cboLeadSource].Requery End Sub The Row Source of 3rd combo contains: SELECT Leads_Sources.ID, Leads_Sources.Lead_Source FROM Leads_Sources WHERE [Lead_Sources].[Lead_Category]=[Lead_Categories].[ID] ORDER BY Leads_Sources.Lead_Source; Problem When I select Market type from cboMarket, the 2nd combo cboLeadCategory loads up the appropriate Categories without a hitch. But when I select a particular Category from it, instead of the 3rd combo loading the lead source names, a modal dialog is displayed asking me to Enter a Parameter. When I enter anything into this prompt (valid or invalid data), I get yet another prompt: Why is this happening? Why isn't the 3rd box loading the source names as desired. Can any one please shed some light on where I am going wrong? Thanks, m^e

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• Silverlight: Binding to a LayoutRoot value from within a DataTemplate

  - by Rosarch

  I have a DataTemplate for a ListBox, where I have several controls that bind to an item. I would also like to bind to a value on LayoutRoot.DataContext. I'm unsure of how to do this. <!--LayoutRoot is the root grid where all page content is placed--> <StackPanel x:Name="LayoutRoot" Background="Transparent"> <ListBox ItemsSource="{Binding Items}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel> <TextBlock Text="{Binding}" /> <TextBlock Text="{Binding ElementName=LayoutRoot, Path=DataContext.Foo}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </StackPanel> public partial class MainPage : PhoneApplicationPage { public string Foo { get { return "the moon"; } } private int startIndex = 1; private IList<string> _data = new List<string>() { "foo", "bar", "baz" }; public IList<string> Items { get { return _data; } } // Constructor public MainPage() { InitializeComponent(); LayoutRoot.DataContext = this; } } This doesn't work; only the _data items are displayed. The following binding errors appear in the Debug output: System.Windows.Data Error: BindingExpression path error: 'Foo' property not found on 'foo' 'System.String' (HashCode=1502598398). BindingExpression: Path='DataContext.Foo' DataItem='System.Windows.Controls.Border' (HashCode=78299055); target element is 'System.Windows.Controls.TextBlock' (Name=''); target property is 'Text' (type 'System.String').. System.Windows.Data Error: BindingExpression path error: 'Foo' property not found on 'bar' 'System.String' (HashCode=696029481). BindingExpression: Path='DataContext.Foo' DataItem='System.Windows.Controls.Border' (HashCode=78298703); target element is 'System.Windows.Controls.TextBlock' (Name=''); target property is 'Text' (type 'System.String').. System.Windows.Data Error: BindingExpression path error: 'Foo' property not found on 'baz' 'System.String' (HashCode=696029489). BindingExpression: Path='DataContext.Foo' DataItem='System.Windows.Controls.Border' (HashCode=78298694); target element is 'System.Windows.Controls.TextBlock' (Name=''); target property is 'Text' (type 'System.String').. Do I have a syntax error somewhere? Update I'm aiming for something that looks like this: foo the moon bar the moon baz the moon Instead, all I'm getting is: foo bar baz

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• new operator overwriting an existing object

  - by dvpdiner2

  I have a custom FastStack class, implemented as a fixed size array and an index into that array. In my copy constructor, I allocate the array and then assign each object from the copy's array into the new array. There's some refcounting in the objects on the stack, hence assignment is used rather than a simple copy. The problem is that when allocating the array, it sometimes overwrites part of the other stack's array. As can be expected, this leads to eventual segmentation faults when that data is dereferenced. class FastStack { private: int m_size, m_ptr; ObjectRef* m_stack; public: FastStack(int size) : m_size(size), m_ptr(-1) { m_stack = new ObjectRef[m_size]; } FastStack(const FastStack& copy) : m_size(copy.m_size), m_ptr(copy.m_ptr) { long a = (long)copy.m_stack[0]; m_stack = new ObjectRef[m_size]; if ((long)copy.m_stack[0] != a) fprintf(stderr, "\nWe have a serious problem!\n\n"); for (int i = 0; i <= m_ptr; i++) m_stack[i] = copy.m_stack[i]; } ~FastStack() { delete[] m_stack; } }; class ObjectRef { private: DataObj* m_obj; public: ObjectRef() : m_obj(0) { } ObjectRef(DataObj* obj) : m_obj(obj) { if (m_obj) m_obj->addRef(); } ObjectRef(const ObjectRef& obj) : m_obj(obj.m_obj) { if (m_obj) m_obj->addRef(); } ~ObjectRef() { if (m_obj) m_obj->delRef(); } ObjectRef& operator=(DataObj* obj) { if (obj) obj->addRef(); if (m_obj) m_obj->delRef(); m_obj = obj; return *this; } ObjectRef& operator=(const ObjectRef& obj) { if (obj.m_obj) obj.m_obj->addRef(); if (m_obj) m_obj->delRef(); m_obj = obj.m_obj; return *this; } }; I see that "We have a serious problem!" line shortly before a segfault, and stepping through it with gdb I can see that one of the ObjectRefs created by new has the same address as the other stack's array. My first instinct is to say that new should never be allocating memory that is already in use, but that clearly seems to be the case here and I am at a complete loss as to what can be done. Added: At the time that I see this happen, m_size = 2 and m_ptr = 0.

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• Passing values between pages in JavaScript

  - by buni

  using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Data.SqlClient; using System.Configuration; using System.Text; using System.Web.Services; using System.IO; namespace T_Smade { public partial class ConferenceManagement : System.Web.UI.Page { volatile int i = 0; protected void Page_Load(object sender, EventArgs e) { GetSessionList(); } public void GetSessionList() { string secondResult = ""; string userName = ""; try { if (HttpContext.Current.User.Identity.IsAuthenticated) { userName = HttpContext.Current.User.Identity.Name; } SqlConnection thisConnection = new SqlConnection(@"data Source=ZOLA-PC;AttachDbFilename=D:\2\5.Devp\my DB\ASPNETDB.MDF;Integrated Security=True"); thisConnection.Open(); SqlCommand secondCommand = thisConnection.CreateCommand(); secondCommand.CommandText = "SELECT myApp_Session.session_id FROM myApp_Session, myApp_Role_in_Session where myApp_Role_in_Session.user_name='" + userName + "' and myApp_Role_in_Session.session_id=myApp_Session.session_id"; SqlDataReader secondReader = secondCommand.ExecuteReader(); while (secondReader.Read()) { secondResult = secondResult + secondReader["session_id"].ToString() + ";"; } secondReader.Close(); SqlCommand thisCommand = thisConnection.CreateCommand(); thisCommand.CommandText = "SELECT * FROM myApp_Session;"; SqlDataReader thisReader = thisCommand.ExecuteReader(); while (thisReader.Read()) { test.Controls.Add(GetLabel(thisReader["session_id"].ToString(), thisReader["session_name"].ToString())); string[] compare = secondResult.Split(';'); foreach (string word in compare) { if (word == thisReader["session_id"].ToString()) { test.Controls.Add(GetButton(thisReader["session_name"].ToString(), "Join Session")); } } } thisReader.Close(); thisConnection.Close(); } catch (SqlException ex) { } } private Button GetButton(string id, string name) { Button b = new Button(); b.Text = name; b.ID = "Button_" + id + i; b.Command += new CommandEventHandler(Button_Click); b.CommandArgument = id; i++; return b; } private Label GetLabel(string id, string name) { Label tb = new Label(); tb.Text = name; tb.ID = id; return tb; } protected void Button_Click(object sender, CommandEventArgs e) { Response.Redirect("EnterSession.aspx?session=" + e.CommandArgument.ToString()); } } I have this code when a user clicks a button www.mypage/EnterSession.aspx?session=session_name in the EnterSession.aspx i have used the code below to track the current URL _gaq.push(['pageTrackerTime._trackEvent', 'Category', 'Action', document.location.href, roundleaveSiteEnd]); Now I would also like to track in the Action parameter the session_name from the previous page.see the code below from the previous page test.Controls.Add(GetButton(thisReader["session_name"].ToString(), "Join Session")); Some idea how to do it? Thanx

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• Best way to have common class shared by both C++ and Ruby?

  - by shuttle87

  I am currently working on a project where a team of us are designing a game, all of us are proficient in ruby and some (but not all) of us are proficient in c++. Initially we made the backend in ruby but we ported it to c++ for more speed. The c++ port of the backend has exactly the same features and algorithms as the original ruby code. However we still have a bunch of code in ruby that does useful things but we want it to now get the data from the c++ classes. Our first thought was that we could save some of the data structures in something like XML or redis and call that, but some of the developers don't like that idea. We don't need anything particularly complex data structures to be passed between the different parts of the code, just tuples, strings and ints. Is there any way of integrating the ruby code so that it can call the c++ stuff natively? Will we need to embed code? Will we have to make a ruby extension? If so are there any good resources/tutorials you could suggest? For example say we have this code in the c++ backend: class The_game{ private: bool printinfo; //print the player diagnostic info at the beginning if true int numplayers; std::vector<Player*> players; string current_action; int action_is_on; // the index of the player in the players array that the action is now on //more code here public: Table(std::vector<Player *> in_players, std::vector<Statistics *> player_stats ,const int in_numplayers); ~Table(); void play_game(); History actions_history; }; class History{ private: int action_sequence_number; std::vector<Action*> hand_actions; public: void print_history(); void add_action(Action* the_action_to_be_added); int get_action_sequence_number(){ return action_sequence_number;} bool history_actions_are_equal(); int last_action_size(int street,int number_of_actions_ago); History(); ~History(); }; Is there any way to natively call something in the actions_history via The_game object in ruby? (The objects in the original ruby code all had the same names and functionality) By this I mean: class MyRubyClass def method1(arg1) puts arg1 self.f() # ... but still available puts cpp_method.the_current_game.actions_history.get_action_sequence_number() end # Constructor: def initialize(arg) puts "In constructor with arg #{arg}" #get the c++ object here and call it cpp_method end end Is this possible? Any advice or suggestions are appreciated.

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• Advance DataGird Header column Drag drop

  - by Atul Yadav

  Hi.. I want to prevent drag drop in some column header . Thanks My code private function _headerShift(evt:IndexChangedEvent):void{ var dg:AdvancedDataGrid= AdvancedDataGrid(evt.currentTarget); var column:AdvancedDataGridColumn = dg.columns[evt.newIndex]; var dropTarget:AdvancedDataGrid = AdvancedDataGrid(evt.currentTarget); if(evt.oldIndex > 3){ evt.stopImmediatePropagation(); evt.preventDefault(); dropTarget.validateNow(); } }

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• Any .NET '#region directive' convention ideas ?

  - by PaN1C_Showt1Me

  I really appreciate the possibility to define regions in your code, as it improves the readability insanely. Anyways, I'd like to have everyone using the same convention in all classes (with the predefined order of all regions) like: Private Fields Constructors Class Properties Event Handlers etc... Do you have any proposition how this division could look like (What regions have sense and what names should they have) and in which order should they be defined ?

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• Android @Override usage

  - by BahaiResearch.com

  (Newbie to Java, old time C# guy.) I have noticed a lot of the use of @Override in Android example code. I thought that all Java methods were by default "Virutal"? What then does @Override do? Example: private class HelloWebViewClient extends WebViewClient { @Override public boolean shouldOverrideUrlLoading(WebView view, String url) { view.loadUrl(url); return true; } }

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• retriving row of grid

  - by madhu

  i have data grid to which data is getting from database.after getting the data i hvve to show entire row information in an alert box.can any one help me thanks in advance. my function code is private function fetch(event:Event):void { var selectedRow:Object = event.currentTarget.selectedItem; Alert.show(""+selectedRow.Details); } iam calling this method on click event of grid

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• Help with simple frame, and graphics in Java

  - by Crystal

  For hw, I'm trying to create a "CustomButton" that has a frame and in that frame, I draw two triangles, and a square over it. It's supposed to give the user the effect of a button press once it is depressed. So for starters, I am trying to set up the beginning graphics, drawing two triangles, and a square. The problem I have is although I set my frame to 200, 200, and the triangles I have drawn I think to the correct ends of my frame size, when I run the program, I have to extend my window to make the whole artwork, my "CustomButton," viewable. Is that normal? Thanks. Code: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class CustomButton { public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { CustomButtonFrame frame = new CustomButtonFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } }); } } class CustomButtonFrame extends JFrame { // constructor for CustomButtonFrame public CustomButtonFrame() { setTitle("Custom Button"); setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); CustomButtonSetup buttonSetup = new CustomButtonSetup(); this.add(buttonSetup); } private static final int DEFAULT_WIDTH = 200; private static final int DEFAULT_HEIGHT = 200; } class CustomButtonSetup extends JComponent { public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g; // first triangle coords int x[] = new int[TRIANGLE_SIDES]; int y[] = new int[TRIANGLE_SIDES]; x[0] = 0; y[0] = 0; x[1] = 200; y[1] = 0; x[2] = 0; y[2] = 200; Polygon firstTriangle = new Polygon(x, y, TRIANGLE_SIDES); // second triangle coords x[0] = 0; y[0] = 200; x[1] = 200; y[1] = 200; x[2] = 200; y[2] = 0; Polygon secondTriangle = new Polygon(x, y, TRIANGLE_SIDES); g2.drawPolygon(firstTriangle); g2.setColor(Color.WHITE); g2.fillPolygon(firstTriangle); g2.drawPolygon(secondTriangle); g2.setColor(Color.GRAY); g2.fillPolygon(secondTriangle); // draw rectangle 10 pixels off border g2.drawRect(10, 10, 180, 180); } public static final int TRIANGLE_SIDES = 3; }

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• How to properly define hash function for a list of objects?

  - by AnSGri

  I have a data structure containing a list of objects, like this: class A { private List<Object> list; } How to properly define a hash function for the list, assuming each element of the list has correct hashCode()? (It's strange that I couldn't easily find the solution via Google.)

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• Confusion over C++ new operator and classes

  - by Nils

  Hi all I created a simple class in C++ which has a private dynamic array. In the constructor I initialize the array using new and in the destructor I free it using delete. When I instantiate the class using Class a = Class(..); it works as expected, however it seems I cannot instantiate it using the new operator (Like Class *a = new Class(..);), I always get a segmentation fault. What I don't understand is when I should use new to instantiate a class and when just call the constructor or should it be possible to instantiate a class either with new or by just calling the constructor. float** A = new float*[3]; for (int i=0; i<3; i++) { A[i] = new float[3]; } A[0][0] = 3; A[0][1] = 3; A[0][2] = 4; A[1][0] = 5; A[1][1] = 6; A[1][2] = 7; A[2][0] = 1; A[2][1] = 2; A[2][2] = 3; Matrix *M = new Matrix(A, 3, 3); delete[] A; delete M; Below the class definition.. class Matrix { private: int width; int height; int stride; float* elements; public: Matrix(float** a, int n, int m); ~Matrix(); }; Matrix::Matrix(float** a, int n, int m) { // n: num rows // m: elem per rows elements = new float[n*m]; for (int i=0; i<n; i++) { for (int j=0; j<m; j++) { elements[i*n + j] = a[n][m]; } } } Matrix::~Matrix() { delete[] elements; }

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