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  • Nhibernate get collection by ICriteria

    - by Andrew Kalashnikov
    Hello, colleagues. I've got a problem at getting my entity. MApping: <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="Clients.Core" namespace="Clients.Core.Domains"> <class name="Sales, Clients.Core" table='sales'> <id name="Id" unsaved-value="0"> <column name="id" not-null="true"/> <generator class="native"/> </id> <property name="Guid"> <column name="guid"/> </property> <set name="Accounts" table="sales_users" lazy="false"> <key column="sales_id" /> <element column="user_id" type="Int32" /> </set> </class> Domain: public class Sales : BaseDomain { ICollection<int> accounts = new List<int>(); public virtual ICollection<int> Accounts { get { return accounts; } set { accounts = value; } } public Sales() { } } I want get query such as SELECT * FROM sales s INNER JOIN sales_users su on su.sales_id=s.id WHERE su.user_id=:N How can i do this through ICriterion object? Thanks a lot.

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  • Efficient way to handle multiple HTMLPurifier configs.

    - by anomareh
    I'm using HTMLPurifier in a current project and I'm not sure about the most efficient way to go about handling multiple configs. For the most part the only major thing changing is the allowed tags. Currently I have a private method, in each class using HTMLPurifier, that gets called when a config is needed and it creates one from the default. I'm not really happy with this as if 2 classes are using the same config, that's duplicating code, and what if a class needs 2 configs? It just feels messy. The one upside to it, is it's lazy in the sense that it's not creating anything until it's needed. The various classes could be used and never have to purify anything. So I don't want to be creating a bunch of config objects that might not even be used. I just recently found out that you can create a new instance of HTMLPurifier and directly set config options like so: $purifier = new HTMLPurifier(); $purifier->config->set('HTML.Allowed', ''); I'm not sure if that's bad form at all or not, and if it isn't I'm not really sure of a good way to put it to use. My latest idea was to create a config handler class that would just return an HTMLPurifier config for use in subsequent purify calls. At some point it could probably be expanded to allow the setting of configs, but just from the start I figured they'd just be hardcoded and run a method parameter through a switch to grab the requested config. Perhaps I could just send the stored purifier instance as an argument and have the method directly set the config on it like shown above? This to me seems the best of the few ways I thought of, though I'm not sure if such a task warrants me creating a class to handle it, and if so, if I'm handling it in the best way. I'm not too familiar with the inner workings of HTMLPurifier so I'm not sure if there are any better mechanisms in place for handling multiple configs. Thanks for any insight anyone can offer.

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  • How to use CodeDomSerializer to serialize an object in .Net?

    - by user341127
    I have a class, which is defined as the following: [ToolboxItem(false)] [DesignTimeVisible(false)] [DesignerSerializer("DevExpress.XtraEditors.Design.RepositoryItemCodeDomSerializer, DevExpress.XtraEditors.v10.1.Design", "System.ComponentModel.Design.Serialization.CodeDomSerializer, System.Design")] [Designer("DevExpress.XtraEditors.Design.BaseRepositoryItemDesigner, DevExpress.XtraEditors.v10.1.Design")] [LicenseProvider(typeof(DXEditorLicenseProvider))] public class RepositoryItem : Component, ISupportInitialize, ICustomTypeDescriptor, IImageCollectionHelper {......} I tried the following code to serialize the object of this class. DesignerSerializationManager m = new System.ComponentModel.Design.Serialization.DesignerSerializationManager(); m.CreateSession(); DevExpress.XtraEditors.Design.RepositoryItemCodeDomSerializer s = m.GetSerializer(typeof(RepositoryItem), typeof(DevExpress.XtraEditors.Design.RepositoryItemCodeDomSerializer)) as DevExpress.XtraEditors.Design.RepositoryItemCodeDomSerializer; RepositoryItem i = persistentRepository1.Items[0]; //m.Container.Add(i); s.Serialize(m,i );// An error "Object reference not set to an instance of an object." happended here. For I am not familiar with CodeDom, I have spent one day to get the way out. I guess the above code has some stupid mistakes. Please give me a hand to show how to serialize AND DeSelialize such objects of the class of Repository. BTW, the reason I don't use any other serializer is that I am supposed not to have rights to know the source code of RepositoryItem and others could inherit RepositoryItem at the same time. And actually I have to deal with RepositoryItem and its descendants. Thank you in advance. Ying

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  • QT: I've inherited from QTreeView. I've inherited from QStandardItem. How do i Style the items?

    - by San Jacinto
    My Google skills must be failing me today. I've inherited from QTreeView to create a TreeView that stores a QStandardItemModel instead of a QAbstractItemModel. I have also inherited from QStandardItem to create a class to store my data in an item as is necessary. I've successfully inserted my derived QStandardItem into my derived QTreeView's QStandardItemModel. Now the trouble is, I can't figure out how to style it. I know that QTreeView has a setStyleSheet(QString) member, but I can't seem to get it working. It may be as simple as I'm not styling the correct attribute. Any pointers would be appreciated. Thanks. For clarity, here are my class defs. class SurveyTreeItem : public QStandardItem { public: SurveyTreeItem(); SurveyTreeItem( const QString & text ); ~SurveyTreeItem(); }; class StandardItemModelTreeView : public QTreeView { public: StandardItemModelTreeView(QWidget* parent = 0); ~StandardItemModelTreeView(); QStandardItemModel* getStandardItemModel(); }; I've tried the following StyleSheets: StandardTreeView::Item { font: 87 12pt 'Arial Black'; } StandardTreeView::QStandardItem { font: 87 12pt 'Arial Black'; } QTreeView::QStandardItem { font: 87 12pt 'Arial Black'; } QTreeView::Item { font: 87 12pt 'Arial Black'; } QTreeView::SurveyTreeItem { font: 87 12pt 'Arial Black'; } StandardTreeView::SurveyTreeItem { font: 87 12pt 'Arial Black'; }

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  • C# Taking a element off each time (stack)

    - by Sef
    Greetings, Have a question considering a program that stimulates a stack.(not using any build in stack features or any such) stack2= 1 2 3 4 5 //single dimension array of 5 elements By calling up a method "pop" the stack should look like the following: Basically taking a element off each time the stack is being "called" up again. stack2= 1 2 3 4 0 stack2= 1 2 3 0 0 stack2= 1 2 0 0 0 stack2= 1 0 0 0 0 stack2= 0 0 0 0 0 - for (int i = 1; i <= 6; i++) { number= TryPop(s2); //use number ShowStack(s2, "s2"); } Basically I already have code that fills my array with values (trough a push method). The pop method should basically take the last value and place it on 0. Then calls up the next stack and place the following on 0 (like shown above in stack2). The current pop method that keeps track of the top index (0 elements = 0 top, 1 element = 1 top etc..). Already includes a underflow warning if this goes on 0 or below (which is correct). public int Pop() { if(top <= 0) { throw new Exception("Stack underflow..."); } else { for (int j = tabel.Length - 1; j >= 0; j--) { //...Really not sure what to do here. } } return number; }/*Pop*/ Since in the other class I already have a loop (for loop shown above) that simulates 6 times the s2 stack. (first stack: 1 2 3 4 0, second stack 1 2 3 0 0 and so on.) How exactly do I take a element off each time? Either I have the entire display on 0 or the 0 in the wrong places / out of index errors. Thanks in advance!

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  • Ruby: add custom properties to built-in classes

    - by dreftymac
    Question: Using Ruby it is simple to add custom methods to existing classes, but how do you add custom properties? Here is an example of what I am trying to do: myarray = Array.new(); myarray.concat([1,2,3]); myarray._meta_ = Hash.new(); # obviously, this wont work myarray._meta_['createdby'] = 'dreftymac'; myarray._meta_['lastupdate'] = '1993-12-12'; ## desired result puts myarray._meta_['createdby']; #=> 'dreftymac' puts myarray.inspect() #=> [1,2,3] The goal is to construct the class definition in such a way that the stuff that does not work in the example above will work as expected. Update: (clarify question) One aspect that was left out of the original question: it is also a goal to add "default values" that would ordinarily be set-up in the initialize method of the class. Update: (why do this) Normally, it is very simple to just create a custom class that inherits from Array (or whatever built-in class you want to emulate). This question derives from some "testing-only" code and is not an attempt to ignore this generally acceptable approach.

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  • Ruby: add custom properties to built-in classes

    - by dreftymac
    Question: Using Ruby it is simple to add custom methods to existing classes, but how do you add custom properties? Here is an example of what I am trying to do: myarray = Array.new(); myarray.concat([1,2,3]); myarray._meta_ = Hash.new(); # obviously, this wont work myarray._meta_['createdby'] = 'dreftymac'; myarray._meta_['lastupdate'] = '1993-12-12'; ## desired result puts myarray._meta_['createdby']; #=> 'dreftymac' puts myarray.inspect() #=> [1,2,3] The goal is to construct the class definition in such a way that the stuff that does not work in the example above will work as expected. Update: (clarify question) One aspect that was left out of the original question: it is also a goal to add "default values" that would ordinarily be set-up in the initialize method of the class. Update: (why do this) Normally, it is very simple to just create a custom class that inherits from Array (or whatever built-in class you want to emulate). This question derives from some "testing-only" code and is not an attempt to ignore this generally acceptable approach.

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  • Is there added overhead to looking up a column in a DataTable by name rather than by index?

    - by Ben McCormack
    In a DataTable object, is there added overhead to looking up a column value by name thisRow("ColumnA") rather than by the column index thisRow(0)? In which scenarios might this be an issue. I work on a team that has lots of experience writing VB6 code and I noticed that didn't do column lookups by name for DataTable objects or data grids. Even in .NET code, we use a set of integer constants to reference column names in these types of objects. I asked our team lead why this was so, and he mentioned that in VB6, there was a lot of overhead in looking up data by column name rather than by index. Is this still true for .NET? Example code (in VB.NET, but same applies to C#): Public Sub TestADOData() Dim dt As New DataTable 'Set up the columns in the DataTable ' dt.Columns.Add(New DataColumn("ID", GetType(Integer))) dt.Columns.Add(New DataColumn("Name", GetType(String))) dt.Columns.Add(New DataColumn("Description", GetType(String))) 'Add some data to the data table ' dt.Rows.Add(1, "Fred", "Pitcher") dt.Rows.Add(3, "Hank", "Center Field") 'Method 1: By Column Name ' For Each r As DataRow In dt.Rows Console.WriteLine( _ "{0,-2} {1,-10} {2,-30}", r("ID"), r("Name"), r("Description")) Next Console.WriteLine() 'Method 2: By Column Name ' For Each r As DataRow In dt.Rows Console.WriteLine("{0,-2} {1,-10} {2,-30}", r(0), r(1), r(2)) Next End Sub Is there an case where method 2 provides a performance advantage over method 1?

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  • ActiveRecord table inheritence using set_table_names

    - by Jinyoung Kim
    Hi, I'm using ActiveRecord in Ruby on Rails. I have a table named documents(Document class) and I want to have another table data_documents(DataDocument) class which is effectively the same except for having different table name. In other words, I want two tables with the same behavior except for table name. class DataDocument < Document #set_table_name "data_documents" self.table_name = "data_documents" end My solution was to use class inheritance as above, yet this resulted in inconsistent SQL statement for create operation where there are both 'documents' table and 'data_documents' table. Can you figure out why and how I can make it work? >> DataDocument.create(:did=>"dd") ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'data_documents.did' in 'where clause': SELECT `documents`.id FROM `documents` WHERE (`data_documents`.`did` = BINARY 'dd') LIMIT 1 from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:320:in `execute' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:595:in `select' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:62:in `select_all'

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  • Change specificity by child

    - by jim red
    hi I'd like to integrate a theme tag to my elements so they appear in diffrent colours. But since the css selectors have the same css specificity the latest overrides the earlier defined rule. this is an example that shows my problem: .... <div class="red"> <div class="box">This should be red</div> <div class="yellow"> ... <div class="box">This should be yellow (nested in x levels under the div.yellow)</div> ... </div> .... and here my css .box { width: 100px; height: 100px; } .yellow { background-color: yellow; } .red { background-color: red; } the box should be listed somewhere, but as soon as it is a sub child of another color definition it should been overwritten. thanks for any help! //jim

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  • Help with Exception Handling in ASP.NET C# Application

    - by Shrewd Demon
    hi, yesterday i posted a question regarding the Exception Handling technique, but i did'nt quite get a precise answer, partly because my question must not have been precise. So i will ask it more precisely. There is a method in my BLL for authenticating user. If a user is authenticated it returns me the instance of the User class which i store in the session object for further references. the method looks something like this... public static UsersEnt LoadUserInfo(string email) { SqlDataReader reader = null; UsersEnt user = null; using (ConnectionManager cm = new ConnectionManager()) { SqlParameter[] parameters = new SqlParameter[1]; parameters[0] = new SqlParameter("@Email", email); try { reader = SQLHelper.ExecuteReader(cm.Connection, "sp_LoadUserInfo", parameters); } catch (SqlException ex) { //this gives me a error object } if (reader.Read()) user = new UsersDF(reader); } return user; } now my problem is suppose if the SP does not exist, then it will throw me an error or any other SQLException for that matter. Since this method is being called from my aspx.cs page i want to return some meaning full message as to what could have gone wrong so that the user understands that there was some problem and that he/she should retry logging-in again. but i can't because the method returns an instance of the User class, so how can i return a message instead ?? i hope i made it clear ! thank you.

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  • Eclipse says I don't implement Enumeration, but I do

    - by Harm De Weirdt
    Goodmorning everybody, I'm having a little problem with a project for school. We are told to make an Iterator that implements Enumeration over a Hashmap. So i made this Enumeration: public Enumeration<Object> getEnumeration() { return new Enumeration<Object>() { private int itemsDone = 0; Collection<Long> keysCollection = getContent().keySet(); Long [] keys = keysCollection.toArray(new Long[keysCollection.size()]); @Override public boolean hasMoreElements() { if(itemsDone < getContent().size() +1 ) { return true; }else { return false; } } @Override public Object nextElement() { return getContent().get(keys[itemsDone++]); } }; } This goes in my Backpack class public class Backpack extends Item implements Carrier, Enumeration<Object>{ The hashmap is returned by getContent(). The problem now is that eclipse keeps telling me I havent implemented the methods from Enumeration. If I use the quick fix it just adds the hasMoreElements() and nextElement() dummy methods in my class. Somehow it doesn't see these methods in the inner class.. Can anyone help me please? Any help is appreciated.

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  • Why would the VB.NET compiler think an interface isn't implemented when it is?

    - by Dan Tao
    I have this happen sometimes, particularly with the INotifyPropertyChanged interface in my experience but I have no idea if the problem is limited to that single interface (which would seem bizarre) or not. Let's say I have some code set up like this. There's an interface with a single event. A class implements that interface. It includes the event. Public Interface INotifyPropertyChanged Event PropertyChanged As PropertyChangedEventHandler End Interface Public Class Person Implements INotifyPropertyChanged Public Event PropertyChanged _ (ByVal sender As Object, ByVal e As PropertyChangedEventArgs) _ Implements INotifyPropertyChanged.PropertyChanged ' more code below ' End Class Every now and then, when I build my project, the compiler will suddenly start acting like the above code is broken. It will report that the Person class does not implement INotifyPropertyChanged because it doesn't have a PropertyChanged event; or it will say the PropertyChanged event can't implement INotifyPropertyChanged.PropertyChanged because their signatures don't match. This is weird enough as it is, but here's the weirdest part: if I just cut out the line starting with Event PropertyChanged and then paste it back in, the error goes away. The project builds. Does anybody have any clue what could be going on here?

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  • Problem calling Java from PHP script

    - by Jack
    I am working on windows. I am running PHP (5.1.3) scripts on Tomcat using PHP/Java bridge. Here is my simple code //test.php <?php require_once("java\Java.inc"); $systemInfo = new Java("Test"); print $systemInfo->foo(); ?> Test.class is in the same folder as test.php. But the php file is not able to locate the test class and I get the following error - Fatal error: Uncaught [[o:Exception]:"java.lang.Exception: CreateInstance failed: new Test. If I use a standard class like below. It works - <?php require_once("java\Java.inc"); $systemInfo = new Java("java.lang.System"); print "Total seconds since January 1, 1970: ".$systemInfo->currentTimeMillis(); ?> What should I do? 1)Should I copy my class to the standard location where all Java classes are kept. (What is this location?) 2) Do some changes in the php.ini file

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  • Declaring functors for comparison ??

    - by Mr.Gando
    Hello, I have seen other people questions but found none that applied to what I'm trying to achieve here. I'm trying to sort Entities via my EntityManager class using std::sort and a std::vector<Entity *> /*Entity.h*/ class Entity { public: float x,y; }; struct compareByX{ bool operator()(const GameEntity &a, const GameEntity &b) { return (a.x < b.x); } }; /*Class EntityManager that uses Entitiy*/ typedef std::vector<Entity *> ENTITY_VECTOR; //Entity reference vector class EntityManager: public Entity { private: ENTITY_VECTOR managedEntities; public: void sortEntitiesX(); }; void EntityManager::sortEntitiesX() { /*perform sorting of the entitiesList by their X value*/ compareByX comparer; std::sort(entityList.begin(), entityList.end(), comparer); } I'm getting a dozen of errors like : error: no match for call to '(compareByX) (GameEntity* const&, GameEntity* const&)' : note: candidates are: bool compareByX::operator()(const GameEntity&, const GameEntity&) I'm not sure but ENTITY_VECTOR is std::vector<Entity *> , and I don't know if that could be the problem when using the compareByX functor ? I'm pretty new to C++, so any kind of help is welcome.

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  • Cannot run a JUnit test case containing threads from Eclipse

    - by Parag
    I am running JUnit test case from Eclipse 3.4.1 . This test case creates a class which starts a thread to do some stuff. When the test method ends it seems that Eclipse is forcibly shutting down the thread. If I run the same test from the command line, then the thread runs properly. Somehow I do not remember running into such problems with Eclipse before. Is this something that was always present in Eclipse or did they add it in 3.4.x ? Here is an example: When I run this test from Eclipse, I get a few printts of the cnt (till about 1800) and then the test case is terminated utomatically. However, if I run the main method, which starts JUnit's TestRunner, then the thread counts indefinetely. import junit.framework.TestCase; import junit.textui.TestRunner; /** * This class shows that Eclipses JUnit test case runner will forcibly * terminate all running threads * * @author pshah * */ public class ThreadTest extends TestCase { static Runnable run = new Runnable() { public void run() { int cnt = 0; while(true) System.out.println(cnt++); } }; public void testThread() { Thread t = new Thread(run); t.start(); } public static void main(String args[]) { TestRunner runner = new TestRunner(); runner.run(ThreadTest.class); } }

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  • Problem locating file in a classpath

    - by Gandalf StormCrow
    I'm trying to read in file content, ex : public void myMethod(){ FileInputStream fstream = new FileInputStream(fileLocation); // Get the object of DataInputStream DataInputStream in = new DataInputStream(fstream); BufferedReader br = new BufferedReader(new InputStreamReader(in)); String strLine; while ((strLine = br.readLine()) != null) { .... .... ..... end while end method And I have at the begining of the class body private String fileLocation; and at the end of a class I have a getter and setter for it. Now I'm trying inject this file location from spring inside bean from this class and I specify the init-method of this class. But I get error cannot find the specified file as if its not on a classpath but it is inside war file? I'm building the project with maven and I put file in src/main/resources This is the error I get when trying to read file : Error: src\main\resources\ids.txt (The system cannot find the path specified) That is when I tried this : FileInputStream fstream = new FileInputStream("src\\main\\resources\\ids.txt"); how to reference the properly from the classpath? EDIT When I edit my code according to @BalusC solution , here is how it looks but I still get null error : ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); InputStream input = classLoader.getResourceAsStream("src/main/resources/ids.txt"); // Get the object of DataInputStream BufferedReader br = new BufferedReader(new InputStreamReader(input)); String strLine; while ((strLine = br.readLine()) != null) { .... .... ..... end while end method

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  • httplib2 giving internal server error 500 with proxy

    - by NJTechie
    Following is the code and error it throws. It works fine without the proxy http = httplib2.Http() . Any pointers are highly appreciated! Usage : http = httplib2.Http(proxy_info = httplib2.ProxyInfo(socks.PROXY_TYPE_HTTP, '74.115.1.11', 80)) main_url = 'http://www.mywebsite.com' response, content = http.request(main_url, 'GET') Error : File "testproxy.py", line 17, in <module> response, content = http.request(main_url, 'GET') File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 1129, in request (response, content) = self._request(conn, authority, uri, request_uri, method, body, headers, redirections, cachekey) File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 901, in _request (response, content) = self._conn_request(conn, request_uri, method, body, headers) File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 862, in _conn_request conn.request(method, request_uri, body, headers) File "/usr/lib/python2.5/httplib.py", line 866, in request self._send_request(method, url, body, headers) File "/usr/lib/python2.5/httplib.py", line 889, in _send_request self.endheaders() File "/usr/lib/python2.5/httplib.py", line 860, in endheaders self._send_output() File "/usr/lib/python2.5/httplib.py", line 732, in _send_output self.send(msg) File "/usr/lib/python2.5/httplib.py", line 699, in send self.connect() File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 740, in connect self.sock.connect(sa) File "/home/kk/bin/pythonlib/socks.py", line 383, in connect self.__negotiatehttp(destpair[0],destpair[1]) File "/home/kk/bin/pythonlib/socks.py", line 349, in __negotiatehttp raise HTTPError((statuscode,statusline[2])) socks.HTTPError: (500, 'Internal Server Error')

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  • .NET: What's the difference between HttpMethod and RequestType of HttpRequest?

    - by Ian Boyd
    The HttpRequest class defines two properties: HttpMethod: Gets the HTTP data transfer method (such as GET, POST, or HEAD) used by the client. public string HttpMethod { get; } The HTTP data transfer method used by the client. and RequestType: Gets or sets the HTTP data transfer method (GET or POST) used by the client. public string RequestType { get; set; } A string representing the HTTP invocation type sent by the client. What is the difference between these two properties? When would i want to use one over the other? Which is the proper one to inspect to see what data transfer method was used by the client? The documentation indicates that HttpMethod will return whatever verb was used: such as GET, POST, or HEAD while the documentation on RequestType seems to indicate only one of two possible values: GET or POST i test with a random sampling of verbs, and both properties seem to support all verbs, and both return the same values: Testing: Client Used HttpMethod RequestType GET GET GET POST POST POST HEAD HEAD HEAD CONNECT CONNECT CONNECT MKCOL MKCOL MKCOL PUT PUT PUT FOOTEST FOOTEST FOOTEST What is the difference between: HttpRequest.HttpMethod HttpRequest.RequestType and when should i use one over the other? Keywords: iis asp.net http httprequest httphandler

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  • Java Concurrency : Synchronized(this) => and this.wait() and this.notify()

    - by jens
    Hello Experts, I would appreciate your help in understand a "Concurrency Example" from: http://forums.sun.com/thread.jspa?threadID=735386 Qute Start: public synchronized void enqueue(T obj) { // do addition to internal list and then... this.notify(); } public synchronized T dequeue() { while (this.size()==0) { this.wait(); } return // something from the queue } Quote End: My Question is: Why is this code valid? = When I synchronize a method like "public synchronized" = then I synchronize on the "Instance of the Object == this". However in the example above: Calling "dequeue" I will get the "lock/monitor" on this Now I am in the dequeue method. As the list is zero, the calling thread will be "waited" From my understanding I have now a deadlock situation, as I will have no chance of ever enquing an object (from an nother thread), as the "dequeue" method is not yet finised and the dequeue "method" holds the lock on this: So I will never ever get the possibility to call "enequeue" as I will not get the "this" lock. Backround: I have exactly the same problem: I have some kind of connection pool (List of Connections) and need to block if all connections are checked. What is the correct way to synchronize the List to block, if size exceeds a limit or is zero? Thank you very much Jens

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  • Can't contravariance be solved with interfaces?

    - by Sir Psycho
    Hi, I'm at the point where I'm starting to grasp contravariance, although I'm trying to work out what the advantage is when an interface can be used instead. Obviously I'm missing something. Here is the c#4 example class Dog : Animal { public Dog(string name) : base(name) { } } class Animal { string _name; public Animal(string name) { _name = name; } public void Walk() { Console.WriteLine(_name + " is walking"); } } Action<Animal> MakeItMove = (ani) => { ani.Walk(); }; Action<Dog> MakeItWalk = MakeItMove; MakeItWalk(new Dog("Sandy")); Same example which works in earlier versions on c# class Dog : Animal { public Dog(string name) : base(name) { } } class Animal : IAnimal { string _name; public Animal(string name) { _name = name; } public void Walk() { Console.WriteLine(_name + " is walking"); } } interface IAnimal { void Walk(); } Action<IAnimal> MakeItMove = (ani) => { ani.Walk(); }; Action<IAnimal> MakeItWalk = MakeItMove; MakeItWalk(new Dog("Sandy")); These may not be the best examples, but I still can't seem to 'get it'. Is the in keywork defined on the action delegate simply a short hand syntax way like lamda is to delegates?

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  • Problem with dropdownbox length

    - by vikitor
    Hello, I'm creating a javascript method that populates lists depending on a radio button selected previously. As it depends on animals or plants to populate it, my problem comes when I have to populate it after it's already been populated. I mean, the plants dropdownlist has 88 elements, and the animals is 888, when I try to come back from animals to plants, I get some of the animals. I know that my controller method is working properly because it returns the values I select, so the problem is the javascript method. Here is the code: if(selector == "sOrder") alert(document.getElementById(selector).options.length); for (i = 0; i < document.getElementById(selector).options.length; i++) { document.getElementById(selector).remove(i); } if (selector == "sOrder") alert(document.getElementById(selector).options.length); document.getElementById(selector).options[0] = new Option("-select-", "0", true, true); for (i = 1; i <= data.length; i++) { document.getElementById(selector).options[i] = new Option(data[i - 1].taxName, data[i - 1].taxRecID);} Here is the strange thing, when I enter the method I try to erase all the elements of the dropdownlist in order to populate it afterwards. As sOrder is the same selector I had previously selected, I get the elements, the thing is that the first alert I get the proper result, 888, but in the second alert, I should get a 0 right? It shows 444, so when I populate it again it just overrides the first 88 plants and then animals till 444. What am I doing wrong? Thank you all in advance, Victor

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  • why assign null value or another default value firstly?

    - by Phsika
    i try to generate some codes. i face to face delegates. Everythings is ok.(Look below) But appearing a warning: you shold assing value why? but second code below is ok. namespace Delegates { class Program { static void Main(string[] args) { HesapMak hesapla = new HesapMak(); hesapla.Calculator = new HesapMak.Hesap(hesapla.Sum); double sonuc = hesapla.Calculator(34, 2); Console.WriteLine("Toplama Sonucu:{0}",sonuc.ToString()); Console.ReadKey(); } } class HesapMak { public double Sum(double s1, double s2) { return s1 + s2; } public double Cikarma(double s1, double s2) { return s1 - s2; } public double Multiply(double s1, double s2) { return s1 * s2; } public double Divide(double s1, double s2) { return s1 / s2; } public delegate double Hesap(double s1, double s2); public Hesap Calculator; ----&#60; they want me assingn value } } namespace Delegates { class Program { static void Main(string[] args) { HesapMak hesapla = new HesapMak(); hesapla.Calculator = new HesapMak.Hesap(hesapla.Sum); double sonuc = hesapla.Calculator(34, 2); Console.WriteLine("Toplama Sonucu:{0}",sonuc.ToString()); Console.ReadKey(); } } class HesapMak { public double Sum(double s1, double s2) { return s1 + s2; } public double Cikarma(double s1, double s2) { return s1 - s2; } public double Multiply(double s1, double s2) { return s1 * s2; } public double Divide(double s1, double s2) { return s1 / s2; } public delegate double Hesap(double s1, double s2); public Hesap Calculator=null; } }

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  • Finding text orientation in image (angle for rotation)

    - by maximus
    There is an image captured by camera, and I need to find the angle of the text in order to rotate it to make the image better for OCR results. So I know that the fourier transform can be used for that purpose, My question is, does it really gives good results or may be it is better to use something different than that? Can you tell me if there is a good method for this purpose? I am afraid that not every image containing the text will give me a good result after using fourier transform method. Actually, if I make like it is written here: link text (see the part related with an example of text image) calculating the logarithm of the magnitude of the Fourier transform of image with text and then thresholding it, I get that points and I can calculate the line approximately passing through them, and after getting the line calculate the angle, and then make an affine transform, But, what if I do not get a good result every time using this method , and make a false transform? Any ideas please to judge wether the result is correct or not, or may be another method is better? The binary image can contain noise, even if there are not so much of them, the angle found as a result can be not accurate.

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  • How can UISearchDisplayController autorelease cause crash in a different view controller?

    - by Tofrizer
    Hi, I have two view controllers A and B. From A, I navigate to view controller B as follows: // in View Controller A // navigateToB method -(void) navigateToB { BViewController *bViewController = [[BViewController alloc] initWithNibName: @"BView" bundle:nil]; bViewController.bProperty1 = SOME_STRING_CONSTANT; bViewController.title = @"A TITLE OF A VC's CHOOSING"; [self.navigationController pushViewController: bViewController animated:YES]; [bViewController release]; //<----- releasing 0x406c1e0 } In BViewController, the property bPropery1 is defined with copy as below (note, B also contains UITableView and other properties): @property (nonatomic, copy) NSString *bProperty1; Everything appeared to work fine when navigating back and forth between A and B. That is until I added a UISearchDisplayController to the table view contained in BViewController. Now when I navigate out of B, back to A, the app crashes. Stack trace shows what looks the search display controller being autoreleased at time of crash: #0 0x009663a7 in ___forwarding___ #1 0x009426c2 in __forwarding_prep_0___ #2 0x018c8539 in -[UISearchDisplayController _destroyManagedTableView] #3 0x018c8ea4 in -[UISearchDisplayController dealloc] #4 0x00285ce5 in NSPopAutoreleasePool NSZombies shows: -[BViewController respondsToSelector:]: message sent to deallocated instance 0x406c1e0 And malloc history on this points to the bViewController already released in A's navigateToB method above: Call [2] [arg=132]: thread_a065e720 |start ... <snip> ..._sendActionsForEvents:withEvent:] | -[UIControl sendAction:to:forEvent:] | - [UIApplication sendAction:to:from:forEvent:] | -[**AViewController navigateToB**] | +[NSObject alloc] | +[NSObject allocWithZone:] | _internal_class_createInstance | _internal_class_createInstanceFromZone | calloc | malloc_zone_calloc Can someone please give me any ideas on what is happening here? In navigateToB method, once the bViewController is released (after pushViewController), that's should be it for bViewController. Nothing else even knows about it as it is local to the navigateToB method block and it has been released. When navigating from B back to A, nothing is invoked in viewDidLoad, viewWillAppear etc that will re-enter navigateToB. It looks like somehow search display controller has a reference to something in my AViewController and so as it is autoreleased it is taking this "something" down with it but I cannot understand how this is possible, especially as I'm using copy to pass data between A and B. I'm going potty over this. I'm sure this is my mistake somewhere and so I turn to you, Stack Overflow legends for any words of wisdom or advice on how to resolve this. Many Thanks.

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