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  • access property value of one class from another internal class in C#

    - by starz26
    how do i acces the property value from an internal class , see below? namespace N1 { public class ClassA { string var1 = null; private ClassB b; public ClassA() { var1 = "one"; b = new ClassB(); } //property public string Var1 { get{ return var1; } } } namespace N1 { internal class ClassB { private void method() { // I need to access the value of Var1( property) from here, how to do this? } } }

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  • Does my GetEnumerator cause a deadlock?

    - by Scott Chamberlain
    I am starting to write my first parallel applications. This partitioner will enumerate over a IDataReader pulling chunkSize records at a time from the data-source. TLDR; version private object _Lock = new object(); public IEnumerator GetEnumerator() { var infoSource = myInforSource.GetEnumerator(); //Will this cause a deadlock if two threads lock (_Lock) //use the enumator at the same time? { while (infoSource.MoveNext()) { yield return infoSource.Current; } } } full code protected class DataSourcePartitioner<object[]> : System.Collections.Concurrent.Partitioner<object[]> { private readonly System.Data.IDataReader _Input; private readonly int _ChunkSize; public DataSourcePartitioner(System.Data.IDataReader input, int chunkSize = 10000) : base() { if (chunkSize < 1) throw new ArgumentOutOfRangeException("chunkSize"); _Input = input; _ChunkSize = chunkSize; } public override bool SupportsDynamicPartitions { get { return true; } } public override IList<IEnumerator<object[]>> GetPartitions(int partitionCount) { var dynamicPartitions = GetDynamicPartitions(); var partitions = new IEnumerator<object[]>[partitionCount]; for (int i = 0; i < partitionCount; i++) { partitions[i] = dynamicPartitions.GetEnumerator(); } return partitions; } public override IEnumerable<object[]> GetDynamicPartitions() { return new ListDynamicPartitions(_Input, _ChunkSize); } private class ListDynamicPartitions : IEnumerable<object[]> { private System.Data.IDataReader _Input; int _ChunkSize; private object _ChunkLock = new object(); public ListDynamicPartitions(System.Data.IDataReader input, int chunkSize) { _Input = input; _ChunkSize = chunkSize; } public IEnumerator<object[]> GetEnumerator() { while (true) { List<object[]> chunk = new List<object[]>(_ChunkSize); lock(_Input) { for (int i = 0; i < _ChunkSize; ++i) { if (!_Input.Read()) break; var values = new object[_Input.FieldCount]; _Input.GetValues(values); chunk.Add(values); } if (chunk.Count == 0) yield break; } var chunkEnumerator = chunk.GetEnumerator(); lock(_ChunkLock) //Will this cause a deadlock? { while (chunkEnumerator.MoveNext()) { yield return chunkEnumerator.Current; } } } } IEnumerator IEnumerable.GetEnumerator() { return ((IEnumerable<object[]>)this).GetEnumerator(); } } } I wanted IEnumerable object it passed back to be thread safe (the MSDN example was so I am assuming PLINQ and TPL could need it) will the lock on _ChunkLock near the bottom help provide thread safety or will it cause a deadlock? From the documentation I could not tell if the lock would be released on the yeld return. Also if there is built in functionality to .net that will do what I am trying to do I would much rather use that. And if you find any other problems with the code I would appreciate it.

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  • nHibernate storage of an object with self referencing many children and many parents

    - by AdamC
    I have an object called MyItem that references children in the same item. How do I set up an nhibernate mapping file to store this item. public class MyItem { public virtual string Id {get;set;} public virtual string Name {get;set;} public virtual string Version {get;set;} public virtual IList<MyItem> Children {get;set;} } So roughly the hbm.xml would be: <class name="MyItem" table="tb_myitem"> <id name="Id" column="id" type="String" length="32"> <generator class="uuid.hex" /> </id> <property name="Name" column="name" /> <property name="Version" column="version" /> <bag name="Children" cascade="all-delete-orphan" lazy="false"> <key column="children_id" /> <one-to-many class="MyItem" not-found="ignore"/> </bag> </class> This wouldn't work I don't think. Perhaps I need to create another class, say MyItemChildren and use that as the Children member and then do the mapping in that class? This would mean having two tables. One table holds the MyItem and the other table holds references from my item. NOTE: A child item could have many parents.

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  • FindBugs and CheckForNull on classes vs. interfaces

    - by ndn
    Is there any way to let FindBugs check and warn me if a CheckForNull annotation is present on the implementation of a method in a class, but not on the declaration of the method in the interface? import javax.annotation.CheckForNull; interface Foo { public String getBar(); } class FooImpl implements Foo { @CheckForNull @Override public String getBar() { return null; } } public class FindBugsDemo { public static void main(String[] args) { Foo foo = new FooImpl(); System.out.println(foo.getBar().length()); } } I just discovered a bug in my application due to a missing null check that was not spotted by FindBugs because CheckForNull was only present on FooImpl, but not on Foo, and I don't want to spot all other locations of this problem manually.

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  • C# to Java Conversion: What is a [DefaultProperty("value")]?

    - by Shiftbit
    I do not understand how the DefaultProperty Metadata tag work or what it signifies. I've read the MSDN and went through the sample but I find it confusing. DefaultPropertyAttribute Class I've read a few blogs and they seem to refer to the indexers. I'm not sure why you would want metadata for your properties? I am coming from a Java background, perhaps a Java analogy would help. [DefaultProperty("Value")] public abstract class FOO<T> : ANY, IBAR<T> { public FOO() { } public FOO(T value) { this.Value = value; } public virtual T Value { get; set; } }

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  • Log information inside a JUnit Suite

    - by Alex Marinescu
    I'm currently trying to write inside a log file the total number of failed tests from a JUnite Suite. My testsuite is defined as follows: @RunWith(Suite.class) @SuiteClasses({Class1.class, Class2.class etc.}) public class SimpleTestSuite {} I tried to define a rule which would increase the total number of errors when a test fails, but apparently my rule is never called. @Rule public MethodRule logWatchRule = new TestWatchman() { public void failed(Throwable e, FrameworkMethod method) { errors += 1; } public void succeeded(FrameworkMethod method) { } }; Any ideas on what I should to do to achieve this behaviour?

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  • How to set specific column settings in JTable?

    - by HansDampf
    How can I make my JTable show specific stuff for each column? Can I use an Object for more than one column? I want to have a column showing the date (dd.mm.yyyy) and another to show the time (hh:mm) but as I have it now it only shows the String representation of the Date object as a whole. public class AppointmentTableModel extends AbstractTableModel { ... @Override public Object getValueAt(int rowIndex, int columnIndex) { return appointments.get(rowIndex).getByColumn(columnIndex); } } public class Appointment { ... public Object getByColumn(int columnIndex) { switch (columnIndex) { case 0: return date; case 1: return date; case 2: return sample; case 3: return sample; case 4: return history; case 5: return comment; } return null; } }

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  • GUI Freezes and Output to JTextField from user input

    - by user2929005
    I am having I hope only two issues currently. I have had help on this on a previous question that I have asked but now I am running into different issues. My current issues now is that I need to print out into a JTextField a sorted array. I do not have questions about how to sort the array I just would like help on how to get the array to print to the JTextField when the Bubble Sort button is pressed. Currently when I press the button it freezes. It freezes at this line. list.add(Integer.valueOf(input.nextInt())); please help Thank you. import java.awt.EventQueue; import javax.swing.*; import java.awt.event.*; import java.util.*; public class Sorting { private JFrame frame; private JTextArea inputArea; private JTextField outputArea; ArrayList<Integer> list = new ArrayList<Integer>(); Scanner input = new Scanner(System.in); /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Sorting window = new Sorting(); window.frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the application. */ public Sorting() { initialize(); } /** * Initialize the contents of the frame. */ private void initialize() { frame = new JFrame(); frame.setBounds(100, 100, 450, 300); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setTitle("Sorting"); frame.getContentPane().setLayout(null); JButton bubbleButton = new JButton("Bubble Sort"); bubbleButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { list.add(Integer.valueOf(input.nextInt())); // for(int i = 0; i < list.size(); i++){ // // } } }); bubbleButton.setBounds(10, 211, 114, 23); frame.getContentPane().add(bubbleButton); JButton mergeButton = new JButton("Merge Sort"); mergeButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { } }); mergeButton.setBounds(305, 211, 114, 23); frame.getContentPane().add(mergeButton); JButton quickButton = new JButton("Quick Sort"); quickButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { } }); quickButton.setBounds(163, 211, 114, 23); frame.getContentPane().add(quickButton); inputArea = new JTextArea(); inputArea.setBounds(10, 36, 414, 51); frame.getContentPane().add(inputArea); outputArea = new JTextField(); outputArea.setEditable(false); outputArea.setBounds(10, 98, 414, 59); frame.getContentPane().add(outputArea); outputArea.setColumns(10); JLabel label = new JLabel("Please Enter 5 Numbers"); label.setHorizontalAlignment(SwingConstants.CENTER); label.setBounds(10, 11, 414, 14); frame.getContentPane().add(label); } }

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  • How do I alias the scala setter method 'myvar_$(myval)' to something more pleasing when in java?

    - by feydr
    I've been converting some code from java to scala lately trying to tech myself the language. Suppose we have this scala class: class Person() { var name:String = "joebob" } Now I want to access it from java so I can't use dot-notation like I would if I was in scala. So I can get my var's contents by issuing: person = Person.new(); System.out.println(person.name()); and set it via: person = Person.new(); person.name_$eq("sallysue"); System.out.println(person.name()); This holds true cause our Person Class looks like this in javap: Compiled from "Person.scala" public class Person extends java.lang.Object implements scala.ScalaObject{ public Person(); public void name_$eq(java.lang.String); public java.lang.String name(); public int $tag() throws java.rmi.RemoteException; } Yes, I could write my own getters/setters but I hate filling classes up with that and it doesn't make a ton of sense considering I already have them -- I just want to alias the _$eq method better. (This actually gets worse when you are dealing with stuff like antlr because then you have to escape it and it ends up looking like person.name_\$eq("newname"); Note: I'd much rather have to put up with this rather than fill my classes with more setter methods. So what would you do in this situation?

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  • Inheritance in XML Schema definition (XSD) for Java objects

    - by bguiz
    Hi, I need to create an XML schema definition (XSD) that describes Java objects. I was wondering how to do this when the objects in question inherit from a common base class with a type parameter. public abstract class Rule<T> { ... } public abstract class TimeRule extends Rule<XTime> { ... } public abstract class LocationRule extends Rule<Location> { ... } public abstract class IntRule extends Rule<Integer> { ... } .... (where XTime and Location are custom classes define elsewhere) How would I go about constructing an XSD that such that I can have XML nodes that represent each of the subclasses of Rule<T> - without the XSD for each of them repeating their common contents? Thank you!

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  • Method Overloading for NULL parameter

    - by Phani
    I have added three methods with parameters: public static void doSomething(Object obj) { System.out.println("Object called"); } public static void doSomething(char[] obj) { System.out.println("Array called"); } public static void doSomething(Integer obj) { System.out.println("Array called"); } When I am calling doSomething(null) , then compiler throws error as ambiguous methods. So Is the issue because Integer and char[] methods or Integer and Object methods?

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  • Using child visitor in C#

    - by Thomas Matthews
    I am setting up a testing component and trying to keep it generic. I want to use a generic Visitor class, but not sure about using descendant classes. Example: public interface Interface_Test_Case { void execute(); void accept(Interface_Test_Visitor v); } public interface Interface_Test_Visitor { void visit(Interface_Test_Case tc); } public interface Interface_Read_Test_Case : Interface_Test_Case { uint read_value(); } public class USB_Read_Test : Interface_Read_Test_Case { void execute() { Console.WriteLine("Executing USB Read Test Case."); } void accept(Interface_Test_Visitor v) { Console.WriteLine("Accepting visitor."); } uint read_value() { Console.WriteLine("Reading value from USB"); return 0; } } public class USB_Read_Visitor : Interface_Test_Visitor { void visit(Interface_Test_Case tc) { Console.WriteLine("Not supported Test Case."); } void visit(Interface_Read_Test_Case rtc) { Console.WriteLine("Not supported Read Test Case."); } void visit(USB_Read_Test urt) { Console.WriteLine("Yay, visiting USB Read Test case."); } } // Code fragment USB_Read_Test test_case; USB_Read_Visitor visitor; test_case.accept(visitor); What are the rules the C# compiler uses to determine which of the methods in USB_Read_Visitor will be executed by the code fragment? I'm trying to factor out dependencies of my testing component. Unfortunately, my current Visitor class contains visit methods for classes not related to the testing component. Am I trying to achieve the impossible?

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  • Losing session after Login - Java

    - by Patrick Villela
    I'm building an application that needs to login to a certain page and make a navigation. I can login, provided that the response contains a string that identifies it. But, when I navigate to the second page, I can't see the page as a logged user, only as anonymous. I'll provide my code. import java.net.*; import java.security.*; import java.security.cert.*; import javax.net.ssl.*; import java.io.*; import java.util.*; public class PostTest { static HttpsURLConnection conn = null; private static class DefaultTrustManager implements X509TrustManager { @Override public void checkClientTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {} @Override public void checkServerTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {} @Override public X509Certificate[] getAcceptedIssuers() { return null; } } public static void main(String[] args) { try { SSLContext ctx = SSLContext.getInstance("TLS"); ctx.init(new KeyManager[0], new TrustManager[] {new DefaultTrustManager()}, new SecureRandom()); SSLContext.setDefault(ctx); String data = URLEncoder.encode("txtUserName", "UTF-8") + "=" + URLEncoder.encode(/*username*/, "UTF-8"); data += "&" + URLEncoder.encode("txtPassword", "UTF-8") + "=" + URLEncoder.encode(/*password*/", "UTF-8"); data += "&" + URLEncoder.encode("envia", "UTF-8") + "=" + URLEncoder.encode("1", "UTF-8"); connectToSSL(/*login url*/); conn.setDoOutput(true); OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream()); wr.write(data); wr.flush(); BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream())); String line; String resposta = ""; while((line = rd.readLine()) != null) { resposta += line + "\n"; } System.out.println("valid login -> " + resposta.contains(/*string that assures me I'm looged in*/)); connectToSSL(/*first navigation page*/); rd = new BufferedReader(new InputStreamReader(conn.getInputStream())); while((line = rd.readLine()) != null) { System.out.println(line); } } catch(Exception e) { e.printStackTrace(); } } private static void connectToSSL(String address) { try { URL url = new URL(address); conn = (HttpsURLConnection) url.openConnection(); conn.setHostnameVerifier(new HostnameVerifier() { @Override public boolean verify(String arg0, SSLSession arg1) { return true; } }); } catch(Exception ex) { ex.printStackTrace(); } } } Any further information, just ask. Thanks in advance.

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  • Best Practice for Summary Footer (and the like) in MVC

    - by benpage
    Simple question on best practice. Say I have: public class Product { public string Name { get; set; } public string Price { get; set; } public int CategoryID { get; set; } public bool IsAvailable { get; set; } } and i have a view using IEnumerable< Product as the model, and i iterate through the Products on the page and want to show the total of the prices at the end of the list, should I use: <%= Model.Sum(x=> x.Price) %> or should I use some other method? This may extend to include more involved things like: <%= Model.Where(x=> x.CategoryID == 5 && x.IsAvailable).Sum(x=> x.Price) %> and even <% foreach (Product p in Model.Where(x=> x.IsAvailable) {%> -- insert html -- <% } %> <% foreach (Product p in Model.Where(x=> !x.IsAvailable) {%> -- insert html -- <% } %> I guess this comes down to should I have that sort of code within my view, or should i be passing it to my view in ViewData? Or perhaps some other way?

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  • How to print each object in a collection in a separate page in Silverlight

    - by Ash
    I would like to know if its possible to print each object in a collection in separate pages using Silverlight printing API. Suppose I have a class Label public class Label { public string Address { get; set; } public string Country { get; set; } public string Name { get; set; } public string Town { get; set; } } I can use print API and print like this. private PrintDocument pd; private void PrintButton_Click(object sender, RoutedEventArgs e) { pd.Print("Test Print"); } private void pd_PrintPage(object sender, PrintPageEventArgs e) { Label labelToPrint = new Label() { Name = "Fake Name", Address = "Fake Address", Country = "Fake Country", Town = "Town" }; var printpage = new LabelPrint(); printpage.DataContext = new LabelPrintViewModel(labelToPrint); e.PageVisual = printpage; } LabelPrint Xaml <StackPanel x:Name="LayoutRoot" VerticalAlignment="Center" HorizontalAlignment="Center"> <TextBlock Text="{Binding Name}" /> <TextBlock Text="{Binding Address}" /> <TextBlock Text="{Binding Town}" /> <TextBlock Text="{Binding Country}" /> </StackPanel> Now, say I've a collection of Label objects, List<Label> labels = new List<Label>() { labelToPrint, labelToPrint, labelToPrint, labelToPrint }; How can I print each object in the list in separate pages ? Thanks for any suggestions ..

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  • xstream handles non-english character

    - by Yan Cheng CHEOK
    I have the following code : /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package helloworld; import com.thoughtworks.xstream.XStream; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import javax.swing.JOptionPane; /** * * @author yccheok */ public class Test { @SuppressWarnings("unchecked") public static <A> A fromXML(Class c, File file) { XStream xStream = new XStream(); InputStream inputStream = null; try { inputStream = new java.io.FileInputStream(file); Object object = xStream.fromXML(inputStream); if (c.isInstance(object)) { return (A)object; } } catch (Exception exp) { exp.printStackTrace(); } finally { if (inputStream != null) { try { inputStream.close(); inputStream = null; } catch (java.io.IOException exp) { exp.printStackTrace(); return null; } } } return null; } @SuppressWarnings("unchecked") public static <A> A fromXML(Class c, String filePath) { return (A)fromXML(c, new File(filePath)); } public static boolean toXML(Object object, File file) { XStream xStream = new XStream(); OutputStream outputStream = null; try { outputStream = new FileOutputStream(file); xStream.toXML(object, outputStream); } catch (Exception exp) { exp.printStackTrace(); return false; } finally { if (outputStream != null) { try { outputStream.close(); outputStream = null; } catch (java.io.IOException exp) { exp.printStackTrace(); return false; } } } return true; } public static boolean toXML(Object object, String filePath) { return toXML(object, new File(filePath)); } public static void main(String args[]) { String s = "\u6210\u4EA4\u91CF"; // print ??? System.out.println(s); // fine! show ??? JOptionPane.showMessageDialog(null, s); toXML(s, "C:\\A.XML"); String o = fromXML(String.class, "C:\\A.XML"); // show ??? JOptionPane.showMessageDialog(null, o); } } I run the following code through command prompt in Windows Vista. 1) May I know why System.out.println unable to print out Chinese Character in console? 2) I open up the xstream file. The saved value is <string>???</string> How can I make xstream save Chinese Character correctly? Thanks.

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  • How do I avoid boxing/unboxing when extending System.Object?

    - by Robert H.
    I'm working on an extension method that's only applicable to reference types. I think, however, it's currently boxing and unboxing the the value. How can I avoid this? namespace System { public static class SystemExtensions { public static TResult GetOrDefaultIfNull<T, TResult>(this T obj, Func<T, TResult> getValue, TResult defaultValue) { if (obj == null) return defaultValue; return getValue(obj); } } } Example usage: public class Foo { public int Bar { get; set; } } In some method: Foo aFooObject = new Foo { Bar = 1 }; Foo nullReference = null; Console.WriteLine(aFooObject.GetOrDefaultIfNull((o) => o.Bar, 0)); // results: 1 Console.WriteLine(nullReference.GetOrDefaultIfNull((o) => o.Bar, 0)); // results: 0

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  • Java: calculate linenumber from charwise position according to the number of "\n"

    - by HH
    I know charwise positions of matches like 1 3 7 8. I need to know their corresponding line number. Example: file.txt Match: X Mathes: 1 3 7 8. Want: 1 2 4 4 $ cat file.txt X2 X 4 56XX [Added: does not notice many linewise matches, there is probably easier way to do it with stacks] $ java testt 1 2 4 $ cat testt.java import java.io.*; import java.util.*; public class testt { public static String data ="X2\nX\n4\n56XX"; public static String[] ar = data.split("\n"); public static void main(String[] args){ HashSet<Integer> hs = new HashSet<Integer>(); Integer numb = 1; for(String s : ar){ if(s.contains("X")){ hs.add(numb); numb++; }else{ numb++; } } for (Integer i : hs){ System.out.println(i); } } }

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  • new Stateful session bean instance without calling lookup

    - by kislo_metal
    Scenario: I have @Singleton UserFactory (@Stateless could be) , its method createSession() generating @Stateful UserSession bean by manual lookup. If I am injecting by DI @EJB - i will get same instance during calling fromFactory() method(as it should be) What I want - is to get new instance of UserSession without preforming lookup. Q1: how could I call new instance of @Stateful session bean? Code: @Singleton @Startup @LocalBean public class UserFactory { @EJB private UserSession session; public UserFactory() { } @Schedule(second = "*/1", minute = "*", hour = "*") public void creatingInstances(){ try { InitialContext ctx = new InitialContext(); UserSession session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } } @Schedule(second = "*/1", minute = "*", hour = "*") public void fromFactory(){ System.out.println("in singleton UUID " +session.getSessionUUID()); } public UserSession creatSession(){ UserSession session2 = null; try { InitialContext ctx = new InitialContext(); session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } return session2; } } As I understand, calling of session.getClass().newInstance(); is not a best idea Q2 : is it true? I am using glassfish v3, ejb 3.1.

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  • Error while reading custom configuration file(app.config)

    - by Newbie
    I am making a custom configuration in my winform application. (It will represent a country-corrency list) First the CountryList class namespace UtilityMethods { public class CountryList : ConfigurationSection { public CountryList() { // // TODO: Add constructor logic here // } [ConfigurationProperty("CountryCurrency", IsRequired = true)] public Hashtable CountryCurrencies { get { return CountryCurrency.GetCountryCurrency(); } } } } The GetCountryCurrency() method is defined in CountryCurrency class as under namespace UtilityMethods { public static class CountryCurrency { public static Hashtable GetCountryCurrency() { Hashtable ht = new Hashtable(); ht.Add("India", "Rupees"); ht.Add("USA", "Dollar"); return ht; } } } The app.config file looks like <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name ="CountryList1" type ="UtilityMethods.CountryList,CountryList,Version=2.0.0.0, Culture=neutral"/> </configSections> <appSettings /> </configuration> And I am calling this from a button_click's event as try { CountryList cList = ConfigurationManager.GetSection("CountryList") as CountryList; Hashtable ht = cList.CountryCurrencies; } catch (Exception ex) { string h = ex.Message; } Upon running the application and clicking on the button I am getting this error Could not load type 'UtilityMethods.CountryList' from assembly 'System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' Please help (dotnet framework : 3.5 Language: C#)

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  • How to use a class's type as the type argument for an inherited collection property in C#

    - by Edelweiss Peimann
    I am trying to create a representation of various types of card that inherit from a generic card class and which all contain references to their owning decks. I tried re-declaring them, as suggested here, but it still won't convert to the specific card type. The code I currently have is as such: public class Deck<T> : List<T> where T : Card { void Shuffle() { throw new NotImplementedException("Shuffle not yet implemented."); } } public class Card { public Deck<Card> OwningDeck { get; set; } } public class FooCard : Card { public Deck<FooCard> OwningDeck { get { return (Deck<FooCard>)base.OwningDeck; } set { OwningDeck = value; } } } The compile-time error I am getting: Error 2 Cannot convert type 'Game.Cards.Deck' to 'Game.Cards.Deck' And a warning suggesting I use a new operator to specify that the hiding is intentional. Would doing so be a violation of convention? Is there a better way? My question to stackoverflow is this: Can what I am trying to do be done elegantly in the .NET type system? If so, can some examples be provided?

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  • Image not loading onto JPanel?

    - by None None
    I have been trying to figure out how to add an image to a JPanel as a background, but still have complete control over the placing of JButtons, JLabels, and etc. This is one method I found, but it is crashing and not loading the image or buttons. Here is the code: import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JButton; import java.awt.BorderLayout; import java.awt.FlowLayout; import java.awt.GridLayout; public class PanelDemo extends JFrame { private static final long serialVersionUID = 1L; private JButton btn1 = new JButton("EASY"); private JButton btn2 = new JButton("MEDIUM"); private JButton btn3 = new JButton("HARD"); private JButton btn4 = new JButton("High Score"); public PanelDemo() { super("Image Panel Demo"); JPanel panel = new ImagePanel( new FlowLayout(FlowLayout.CENTER, 50, 180)); JPanel panelbtn = new JPanel(new GridLayout(4, 1)); btn1.setBackground(new java.awt.Color(0, 0, 0)); btn1.setFont(new java.awt.Font("Showcard Gothic", 1, 24)); btn1.setForeground(new java.awt.Color(0, 255, 102)); btn2.setBackground(new java.awt.Color(0, 0, 0)); btn2.setFont(new java.awt.Font("Showcard Gothic", 1, 24)); btn2.setForeground(new java.awt.Color(0, 255, 102)); btn3.setBackground(new java.awt.Color(0, 0, 0)); btn3.setFont(new java.awt.Font("Showcard Gothic", 1, 24)); btn3.setForeground(new java.awt.Color(0, 255, 102)); btn4.setBackground(new java.awt.Color(0, 0, 0)); btn4.setFont(new java.awt.Font("Showcard Gothic", 1, 24)); btn4.setForeground(new java.awt.Color(0, 255, 102)); panel.add(panelbtn); panelbtn.add(btn1); panelbtn.add(btn2); panelbtn.add(btn3); panelbtn.add(btn4); add(panel, BorderLayout.CENTER); setSize(640, 480); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } public static void main(String... args) { new PanelDemo().setVisible(true); } } ImagePanel.java import java.awt.Graphics; import java.awt.Image; import java.awt.LayoutManager; import javax.swing.ImageIcon; import javax.swing.JPanel; public class ImagePanel extends JPanel { private static final long serialVersionUID = 1L; String imageFile = "/rsc/img/background.jpg"; public ImagePanel() { super(); } public ImagePanel(String image) { super(); this.imageFile = image; } public ImagePanel(LayoutManager layout) { super(layout); } public void paintComponent(Graphics g) { ImageIcon imageicon = new ImageIcon(getClass().getResource(imageFile)); Image image = imageicon.getImage(); super.paintComponent(g); if (image != null) g.drawImage(image, 0, 0, getWidth(), getHeight(), this); } } Error: Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at javax.swing.ImageIcon.<init>(Unknown Source) at ImagePanel.paintComponent(ImagePanel.java:27) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JLayeredPane.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source) at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source) at sun.awt.SunGraphicsCallback.runComponents(Unknown Source) at java.awt.Container.paint(Unknown Source) at java.awt.Window.paint(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Also, if anyone knows of a better way to put a background image on a JPanel, pease do tell. Thank you in advance.

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  • Circular reference problem Singleton

    - by Ismail
    I'm trying to creating a Singleton class like below where MyRepository lies in separate DAL project. It's causing me a circular reference problem because GetMySingleTon() method returns MySingleTon class and needs its access. Same way I need MyRepository access in constructor of MySingleTon class. public class MySingleTon { static MySingleTon() { if (Instance == null) { MyRepository rep = new MyRepository(); Instance = rep.GetMySingleTon(); } } public static MySingleTon Instance { get; private set; } public string prop1 { get; set; } public string prop2 { get; set; } }

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