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  • Correct OOP design without getters?

    - by kane77
    I recently read that getters/setters are evil and I have to say it makes sense, yet when I started learning OOP one of the first things I learned was "Encapsulate your fields" so I learned to create class give it some fields, create getters, setters for them and create constructor where I initialize these fields. And every time some other class needs to manipulate this object (or for instance display it) I pass it the object and it manipulate it using getters/setters. I can see problems with this approach. But how to do it right? For instance displaying/rendering object that is "data" class - let's say Person, that has name and date of birth. Should the class have method for displaying the object where some Renderer would be passed as an argument? Wouldn't that violate principle that class should have only one purpose (in this case store state) so it should not care about presentation of this object. Can you suggest some good resources where best practices in OOP design are presented? I'm planning to start a project in my spare time and I want it to be my learning project in correct OOP design..

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  • Django - Form validation error

    - by Igor G.
    Hello, I have a model like this: class Entity(models.Model): entity_name = models.CharField(max_length=100) entity_id = models.CharField(max_length=30, primary_key=True) entity_parent = models.CharField(max_length=100, null=True) photo_id = models.CharField(max_length=100, null=True) username = models.CharField(max_length=100, null=True) date_matched_on = models.CharField(max_length=100, null=True) status = models.CharField(max_length=30, default="Checked In") def __unicode__(self): return self.entity_name class Meta: app_label = 'match' ordering = ('entity_name','date_matched_on') verbose_name_plural='Entities' I also have a view like this: def photo_match(request): ''' performs an update in the db when a user chooses a photo ''' form = EntityForm(request.POST) form.save() And my EntityForm looks like this: class EntityForm(ModelForm): class Meta: model = Entity My template's form returns a POST back to the view with the following values: {u'username': [u'admin'], u'entity_parent': [u'PERSON'], u'entity_id': [u'152097'], u'photo_id': [u'2200734'], u'entity_name': [u'A.J. McLean'], u'status': [u'Checked Out'], u'date_matched_on': [u'5/20/2010 10:57 AM']} And form.save() throws this error: Exception in photo_match: The Entity could not be changed because the data didn't validate. I have been trying to figure out why this is happening, but cannot pinpoint the exact problem. I can change my Entities in the admin interface just fine. If anybody has a clue about this I would greatly appreciate it! Thanks, Igor

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  • Overriding LINQ extension methods

    - by Ruben Vermeersch
    Is there a way to override extension methods (provide a better implementation), without explicitly having to cast to them? I'm implementing a data type that is able to handle certain operations more efficiently than the default extension methods, but I'd like to keep the generality of IEnumerable. That way any IEnumerable can be passed, but when my class is passed in, it should be more efficient. As a toy example, consider the following: // Compile: dmcs -out:test.exe test.cs using System; namespace Test { public interface IBoat { void Float (); } public class NiceBoat : IBoat { public void Float () { Console.WriteLine ("NiceBoat floating!"); } } public class NicerBoat : IBoat { public void Float () { Console.WriteLine ("NicerBoat floating!"); } public void BlowHorn () { Console.WriteLine ("NicerBoat: TOOOOOT!"); } } public static class BoatExtensions { public static void BlowHorn (this IBoat boat) { Console.WriteLine ("Patched on horn for {0}: TWEET", boat.GetType().Name); } } public class TestApp { static void Main (string [] args) { IBoat niceboat = new NiceBoat (); IBoat nicerboat = new NicerBoat (); Console.WriteLine ("## Both should float:"); niceboat.Float (); nicerboat.Float (); // Output: // NiceBoat floating! // NicerBoat floating! Console.WriteLine (); Console.WriteLine ("## One has an awesome horn:"); niceboat.BlowHorn (); nicerboat.BlowHorn (); // Output: // Patched on horn for NiceBoat: TWEET // Patched on horn for NicerBoat: TWEET Console.WriteLine (); Console.WriteLine ("## That didn't work, but it does when we cast:"); (niceboat as NiceBoat).BlowHorn (); (nicerboat as NicerBoat).BlowHorn (); // Output: // Patched on horn for NiceBoat: TWEET // NicerBoat: TOOOOOT! Console.WriteLine (); Console.WriteLine ("## Problem is: I don't always know the type of the objects."); Console.WriteLine ("## How can I make it use the class objects when the are"); Console.WriteLine ("## implemented and extension methods when they are not,"); Console.WriteLine ("## without having to explicitely cast?"); } } } Is there a way to get the behavior from the second case, without explict casting? Can this problem be avoided?

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  • Django Foreign key queries

    - by Hulk
    In the following model: class header(models.Model): title = models.CharField(max_length = 255) created_by = models.CharField(max_length = 255) def __unicode__(self): return self.id() class criteria(models.Model): details = models.CharField(max_length = 255) headerid = models.ForeignKey(header) def __unicode__(self): return self.id() class options(models.Model): opt_details = models.CharField(max_length = 255) headerid = models.ForeignKey(header) def __unicode__(self): return self.id() If there is a row in the database for table header as Id=1, title=value-mart , createdby=CEO How do i query criteria and options tables to get all the values related to header table id=1 Also can some one please suggest a good link for queries examples, Thanks..

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  • How do I get the member to which my custom attribute was applied?

    - by Sarah Vessels
    I'm creating a custom attribute in C# and I want to do different things based on whether the attribute is applied to a method versus a property. At first I was going to do new StackTrace().GetFrame(1).GetMethod() in my custom attribute constructor to see what method called the attribute constructor, but now I'm unsure what that will give me. What if the attribute was applied to a property? Would GetMethod() return a MethodBase instance for that property? Is there a different way of getting the member to which an attribute was applied in C#? [AttributeUsage(AttributeTargets.Method | AttributeTargets.Property, AllowMultiple = true)] public class MyCustomAttribute : Attribute Update: okay, I might have been asking the wrong question. From within a custom attribute class, how do I get the member (or the class containing the member) to which my custom attribute was applied? Aaronaught suggested against walking up the stack to find the class member to which my attribute was applied, but how else would I get this information from within the constructor of my attribute?

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  • Statically Compiling QWebKit 4.6.2

    - by geeko
    I tried to compile Qt+Webkit statically with MS VS 2008 and this worked. C:\Qt\4.6.2configure -release -static -opensource -no-fast -no-exceptions -no-accessibility -no-rtti -no-stl -no-opengl -no-openvg -no-incredibuild-xge -no-style-plastique -no-style-cleanlooks -no-style-motif -no-style-cde -no-style-windowsce -no-style-windowsmobile -no-style-s60 -no-gif -no-libpng -no-libtiff -no-libjpeg -no-libmng -no-qt3support -no-mmx -no-3dnow -no-sse -no-sse2 -no-iwmmxt -no-openssl -no-dbus -platform win32-msvc2008 -arch windows -no-phonon -no-phonon-backend -no-multimedia -no-audio-backend -no-script -no-scripttools -webkit -no-declarative However, I get these errors whenever building a project that links statically to QWebKit: 1 Creating library C:\Users\Geeko\Desktop\Qt\TestQ\Release\TestQ.lib and object C:\Users\Geeko\Desktop\Qt\TestQ\Release\TestQ.exp 1QtWebKit.lib(PluginPackageWin.obj) : error LNK2019: unresolved external symbol _VerQueryValueW@16 referenced in function "class WebCore::String __cdecl WebCore::getVersionInfo(void * const,class WebCore::String const &)" (?getVersionInfo@WebCore@@YA?AVString@1@QAXABV21@@Z) 1QtWebKit.lib(PluginPackageWin.obj) : error LNK2019: unresolved external symbol _GetFileVersionInfoW@16 referenced in function "private: bool __thiscall WebCore::PluginPackage::fetchInfo(void)" (?fetchInfo@PluginPackage@WebCore@@AAE_NXZ) 1QtWebKit.lib(PluginPackageWin.obj) : error LNK2019: unresolved external symbol _GetFileVersionInfoSizeW@8 referenced in function "private: bool __thiscall WebCore::PluginPackage::fetchInfo(void)" (?fetchInfo@PluginPackage@WebCore@@AAE_NXZ) 1QtWebKit.lib(PluginDatabaseWin.obj) : error LNK2019: unresolved external symbol _imp_PathRemoveFileSpecW@4 referenced in function "class WebCore::String __cdecl WebCore::safariPluginsDirectory(void)" (?safariPluginsDirectory@WebCore@@YA?AVString@1@XZ) 1QtWebKit.lib(PluginDatabaseWin.obj) : error LNK2019: unresolved external symbol _imp_SHGetValueW@24 referenced in function "void __cdecl WebCore::addWindowsMediaPlayerPluginDirectory(class WTF::Vector &)" (?addWindowsMediaPlayerPluginDirectory@WebCore@@YAXAAV?$Vector@VString@WebCore@@$0A@@WTF@@@Z) 1QtWebKit.lib(PluginDatabaseWin.obj) : error LNK2019: unresolved external symbol _imp_PathCombineW@12 referenced in function "void __cdecl WebCore::addMacromediaPluginDirectories(class WTF::Vector &)" (?addMacromediaPluginDirectories@WebCore@@YAXAAV?$Vector@VString@WebCore@@$0A@@WTF@@@Z) 1C:\Users\Geeko\Desktop\Qt\TestQ\Release\TestQ.exe : fatal error LNK1120: 6 unresolved externals Do I need to check something in the Qt project options ? I have QtCore, QtGui, Network and WebKit checked.

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  • iPhone app running in Instruments fails with unrecognized selector

    - by Mark Smith
    I have an app that appears to run without problems in normal use. The Clang Static Analyzer reports no problems either. When I try to run it in Instruments, it fails with an unrecognized selector exception. The offending line is a simple property setter of the form: self.bar = baz; To figure out what's going on, I added an NSLog() call immediately above it: NSLog(@"class = %@ responds = %d", [self class], [self respondsToSelector:@selector(setBar:)]); self.bar = baz; On the emulator (without Instruments) and on a device, this shows exactly what I'd expect: class = Foo responds = 1 When running under Instruments, I get: class = Foo responds = 0 I'm stumped as to what could cause this. Perhaps a different memory location is getting tromped on when it's in the Instruments environment? Can anyone suggest how I might debug this?

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  • Doctrine stupid or me stupid?

    - by ropstah
    I want to use a single Doctrine install on our server and serve multiple websites. Naturally the models should be maintained in the websites' modelsfolder. I have everything up (and not running) like so: Doctrine @ /CustomFramework/Doctrine Websites @ /var/www/vhosts/custom1.com/ /var/www/vhosts/custom2.com/ Generating works fine, all models are delivered in /application_folder/models and /application_folder/models/generated for the correct website. I've added Doctrine::loadModels('path_to_models') in the bootstrap file for each website, and also registered the autoloaded. But.... This is the autoloader code: public static function autoload($className) { if (strpos($className, 'sfYaml') === 0) { require dirname(__FILE__) . '/Parser/sfYaml/' . $className . '.php'; return true; } if (0 !== stripos($className, 'Doctrine_') || class_exists($className, false) || interface_exists($className, false)) { return false; } $class = self::getPath() . DIRECTORY_SEPARATOR . str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php'; if (file_exists($class)) { require $class; return true; } return false; } Am I stupid, or is the autoloader really doing this: $class = self::getPath() . DIRECTORY_SEPARATOR . str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php'; or, in other words: Does it require me to have ALL my generated doctrine classes inside the Doctrine app directory? Or in other words, do I need a single Doctrine installation for each website? I'm getting an error that the BaseXXX class cannot be found. So the autoloading doesn't function correctly. I really hope i'm doing something wrong.. anyone?

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  • Problem with JS Selectbox Function

    - by Thomas
    I have a selectbox with three options. When a user selects one of the three options, I want a specific div to appear below it. I am trying to write the code that dictates which specific box is to appear when each of the three options is selected. So far, I have only worked on the code that pertains to the first option. However, whenever the user selects any of the three options from the selectbox, the function for the first option is triggered and the div is displayed. My question is two part: 1) How do I write a conditional function that specifically targets the selected option 2) What is the best way to accomplish what I have described above; How do I efficiently go about defining three different functions for three different options in a select box? Here is the function I was working on for the first option: $(document).ready(function(){ var subTableDiv = $("div.subTableDiv"); var subTableDiv1 = $("div.subTableDiv1"); var subTableDiv2 = $("div.subTableDiv2"); subTableDiv.hide(); subTableDiv1.hide(); subTableDiv2.hide(); var selectmenu=document.getElementById("customfields-s-18-s"); selectmenu.onchange=function(){ //run some code when "onchange" event fires var chosenoption=this.options[this.selectedIndex].value //this refers to "selectmenu" if (chosenoption.value ="Co-Op"){ subTableDiv1.slideDown("medium"); } } }); Html: <tr> <div> <select name="customfields-s-18-s" class="dropdown" id="customfields-s-18-s" > <option value="Condominium"> Condominium</option> <option value="Co-Op"> Co-Op</option> <option value="Condop"> Condop</option> </select> </div> </tr> <tr class="subTable"> <td colspan="2"> <div style="background-color: #EEEEEE; border: 1px solid #CCCCCC; padding: 10px;" id="Condominium" class="subTableDiv">Hi There! This is the first Box</div> </td> </tr> <tr class="subTable"> <td colspan="2"> <div style="background-color: #EEEEEE; border: 1px solid #CCCCCC; padding: 10px;" id="Co-Op" class="subTableDiv1">Hi There! This is the Second Box</div> </td> </tr> <tr class="subTable"> <td colspan="2"> <div style="background-color: #EEEEEE; border: 1px solid #CCCCCC; padding: 10px;" id="Condop" class="subTableDiv2">Hi There! This is the Third Box.</div> </td> </tr>

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  • Save blob to DB using hibernate

    - by Link123
    Hey! I tried save file to MySQL using blob with hibernate3. But I always have java.lang.UnsupportedOperationException: Blob may not be manipulated from creating session org.hibernate.lob.BlobImpl.excep(BlobImpl.java:127) Here some code. package com.uni.domain; public class File extends Identifier { private byte[] data; private String contentType; public byte[] getData() { return data; } public File() {} public void setData(byte[] photo) { this.data = photo; } public boolean isNew() { return true; } public String getContentType() { return contentType; } public void setContentType(String contentType) { this.contentType = contentType; } } package com.uni.domain; import org.hibernate.Hibernate; import org.hibernate.HibernateException; import org.hibernate.usertype.UserType; import java.io.InputStream; import java.io.OutputStream; import java.io.Serializable; import java.sql.*; import java.util.Arrays; public class PhotoType implements UserType { public int[] sqlTypes() { return new int[]{Types.BLOB}; } public Class returnedClass() { return byte[].class; } public boolean equals(Object o, Object o1) throws HibernateException { return Arrays.equals((byte[]) o, (byte[]) o1); } public int hashCode(Object o) throws HibernateException { return o.hashCode(); } public Object nullSafeGet(ResultSet resultSet, String[] strings, Object o) throws HibernateException, SQLException { Blob blob = resultSet.getBlob(strings[0]); return blob.getBytes(1, (int) blob.length()); } public void nullSafeSet(PreparedStatement st, Object value, int index) throws HibernateException, SQLException { st.setBlob(index, Hibernate.createBlob((byte[]) value)); } public Object deepCopy(Object value) { if (value == null) return null; byte[] bytes = (byte[]) value; byte[] result = new byte[bytes.length]; System.arraycopy(bytes, 0, result, 0, bytes.length); return result; } public boolean isMutable() { return true; } public Serializable disassemble(Object o) throws HibernateException { return null; . } public Object assemble(Serializable serializable, Object o) throws HibernateException { return null; . } public Object replace(Object o, Object o1, Object o2) throws HibernateException { return null; . } <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.uni.domain"> <class name="com.uni.domain.File"> <id name="id"> <generator class="native"/> </id> <property name="data" type="com.uni.domain.FleType"/> <property name="contentType"/> </class> </hibernate-mapping> Help me please. Where I’m wrong?

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  • How to use an OSGi service from a web application?

    - by Jaime Soriano
    I'm trying to develop a web application that is going to be launched from a HTTP OSGi service, this application needs to use other OSGi service (db4o OSGi), for what I need a reference to a BundleContext. I have tried two different approaches to get the OSGi context in the web application: Store the BundleContext of the Activator in an static field of a class that the web service can import and use. Use FrameworkUtil.getBundle(this.getClass()).getBundleContext() (being this an instance of MainPage, a class of the web application). I think that first option is completely wrong, but anyway I'm having problems with the class loaders in both options. In the second one it raises a LinkageError: java.lang.LinkageError: loader constraint violation: loader (instance of org/apache/felix/framework/ModuleImpl$ModuleClassLoader) previously initiated loading for a different type with name "com/db4o/ObjectContainer" Also tried with Equinox and I have a similar error: java.lang.LinkageError: loader constraint violation: loader (instance of org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) previously initiated loading for a different type with name "com/db4o/ObjectContainer" The code that provokes the exception is: ServiceReference reference = context.getServiceReference(Db4oService.class.getName()); Db4oService service = (Db4oService)context.getService(reference); database = service.openFile("foo.db"); The exception is raised in the last line, database class is ObjectContainer, if I change the type of this variable to Object exception is not raised, but It's not useful as an Object :)

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  • jQuery sortable (how to customize the clickable area inside the sortable box)

    - by cvack
    I have this jQuery code: $(".right_box_holder").sortable({ update : function () { var order = $('.right_box_holder').sortable('serialize'); $.get("right_menu_functions.php?change_sortorder&"+order); } }); and this HTML code: <div class='right_box_holder'> <div class='right_box' id='box_0'> // sort box 0 </div> <div class='right_box' id='box_1'> // sort box 1 </div> <div class='right_box' id='box_2'> // sort box 2 </div> </div> As it is now, I can click anywhere inside .right_box and move it. I want to disable this and make a button / icon inside .right_box which the user have to click on to drag the box. Is this possible?

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  • implement alphabetical scroll in MPMediaPickerController app

    - by Pavan
    If you go to the iphone library and then go to songs, you will see the songs being displayed in a similar way to the MPMediaItemPicker class does. The only difference is that the ipod application shows the search bar right at the top of the list and also a nice alphabetical scroll on the right hand side whereas the MPMediaItemPicker class only isplays a simple scroll going up and down. How can i implement an alphabetical scroll on the right in the MPMediaItemPicker class? Can someone please help me.

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  • How to CompareTo two Object without known about their real type

    - by Kamil
    I have to implement a one linked list but it should put object in appropriate position. Everything was OK when I use it in conjunction with specific class, but when I tried make it universal and argument of method insert was Object some problem appeared. When I want to input Object in right position I should use CompareTo method, but there isn't method in Object class! The problem is how to compare two object elements without known about their real types. Maybe I should use generic class type? But what about CompareTo? Or maybe combine with Element class and place CompareTo there? I suppose it is feasible. :) public void insert(Object o) { Element el = new Element(o); // initializing and setting iterators while(!it.isDone() && ((it.current().getValue())).CompareTo(o)<0) // it.current() returns Element of List { //move interators } //... }

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  • Proper use of Q_OBJECT?

    - by Jen
    If I derive my class from QObject (or a subclass), the Qt documentation says that I have to put the Q_OBJECT macro into my class declaration. It also ways I need to "run the meta-object compiler" for my class. I have no idea how to do this. Is this something I need to add to the .pro file? Do I need to edit the makefile? This seems overly complicated for a simple derived class. I'm using Qt Creator.

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  • Rhino Mocks verify a private method is called from a public method

    - by slowcelica
    I have been trying to figure this one out, how do i test that a private method is called with rhino mocks with in the class that I am testing. So my class would be something like this. Public class Foo { public bool DoSomething() { if(somevalue) { //DoSomething; } else { ReportFailure("Failure"); } } private void ReportFailure(string message) { //DoSomeStuff; } } So my unit test is on class Foo and method DoSomething() I want to check and make sure that a certain message is passed to ReportFailure if somevalue is false, using rhino mocks.

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  • Using a custom form in a modelformset factory?

    - by jamida
    I'd like to be able to use a customized form in a modelformset_factory. For example: models.py class Author(models.Model): name = models.CharField() address = models.CharField() class AuthorForm(ModelForm): class Meta: model = Author views.py def test_render(request): myModelFormset = modelformset_factory(Author) items = Author.objects.all() formsetInstance = myModelFormset(queryset = items) return render_to_response('template',locals()) The above code works just fine, but note I'm NOT using AuthorForm. The question is how can I get the modelformset_factory to use the AuthorForm (which I plan to customize later) instead of making a default Author form?

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  • Centering Div in the middle of the page

    - by shinjuo
    What is the best way to center the entire page in the middle of the web browser? <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta content="text/html; charset=utf-8" http-equiv="Content-Type" /> <title>test.html</title> <style type="text/css"> .testimonials_png { position: absolute; left:20px; top:397px; width:220px; height:395px; background: url("test_files/testimonials.png") no-repeat; } .homeLink_png { position: absolute; left:-1px; top:243px; width:203px; height:75px; background: url("test_files/homeLink.png") no-repeat; } .sidingLink_png { position: absolute; left:202px; top:243px; width:180px; height:75px; background: url("test_files/sidingLink.png") no-repeat; } .windowsLink_png { position: absolute; left:382px; top:243px; width:181px; height:75px; background: url("test_files/windowsLink.png") no-repeat; } .roofingLink_png { position: absolute; left:563px; top:243px; width:183px; height:75px; background: url("test_files/roofingLink.png") no-repeat; } .aboutLink_png { position: absolute; left:746px; top:243px; width:205px; height:75px; background: url("test_files/aboutLink.png") no-repeat; } .banner_png { position: absolute; left:0px; top:0px; width:950px; height:243px; background: url("test_files/banner.png") no-repeat; } </style> </head> <body> <div class="testimonials_png"> </div> <div class="homeLink_png"> </div> <div class="sidingLink_png"> </div> <div class="windowsLink_png"> </div> <div class="roofingLink_png"> </div> <div class="aboutLink_png"> </div> <div class="banner_png"> </div> </body> </html>

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  • How to do custom display and auto-select in django admin multi-select field?

    - by rsp
    I'm new to django, so please feel free to tell me if I'm doing this incorrectly. I am trying to create a django ordering system. My order model: class Order(models.Model): ordered_by = models.ForeignKey(User, limit_choices_to = {'groups__name': "Managers", 'is_active': 1}) in my admin ANY user can enter an order, but ordered_by must be someone in the group "managers" (this is the behavior I want). Now, if the logged in user happens to be a manager I want it to automatically fill in the field with that logged in user. I have accomplished this by: class OrderAdmin(admin.ModelAdmin): def formfield_for_foreignkey(self, db_field, request, **kwargs): if db_field.name == "ordered_by": if request.user in User.objects.filter(groups__name='Managers', is_active=1): kwargs["initial"] = request.user.id kwargs["empty_label"] = "-------------" return db_field.formfield(**kwargs) return super(OrderAdmin, self).formfield_for_foreignkey(db_field, request, **kwargs) This also works, but the admin puts the username as the display for the select box by default. It would be nice to have the user's real name listed. I was able to do it with this: class UserModelMultipleChoiceField(forms.ModelMultipleChoiceField): def label_from_instance(self, obj): return obj.first_name + " " + obj.last_name class OrderForm(forms.ModelForm): ordered_by = UserModelChoiceField(queryset=User.objects.all().filter(groups__name='Managers', is_active=1)) class OrderAdmin(admin.ModelAdmin): form = OrderForm My problem: I can't to both of these. If I put in the formfield_for_foreignkey function and add form = OrderForm to use my custom "UserModelChoiceField", it puts the nice name display but it won't select the currently logged in user. I'm new to this, but my guess is that when I use UserModelChoiceField it "erases" the info passed in via formfield_for_foreignkey. Do I need to use the super() function somehow to pass on this info? or something completely different?

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  • Best way to handle multiple tables to replace one big table in Rails? (e.g. 'Books1', 'Books2', etc.

    - by mikep
    Hello, I've decided to use multiple tables for an entity (e.g. Books1, Books2, Books3, etc.), instead of just one main table which could end up having a lot of rows (e.g. just Books). I'm doing this to try and to avoid a potential future performance drop that could come with having too many rows in one table. With that, I'm looking for a good way to handle this in Rails, mainly by trying to avoid loading a bunch of unused associations. (I know that I could use a partition for this, but, for now, I've decided to go the 'multiple tables' route.) Each user has their books placed into a specific table. The actual book table is chosen when the user is created, and all of their books go into the same table. I'm going to split the adds across the tables. The goal is to try and keep each table pretty much even -- but that's a different issue. One thing I don't particularly want to have is a bunch of unused associations in the User class. Right now, it looks like I'd have to do the following: class User < ActiveRecord::Base has_many :books1, :books2, :books3, :books4, :books5 end class Books1 < ActiveRecord::Base belongs_to :user end class Books2 < ActiveRecord::Base belongs_to :user end class Books3 < ActiveRecord::Base belongs_to :user end I'm assuming that the main performance hit would come in terms of memory and possibly some method call overhead for each User object, since it has to load all of those associations, which in turn creates all of those nice, dynamic model accessor methods like User.find_by_. But for each specific user, only one of the book tables would be usable/applicable, since all of a user's books are stored in the same table. So, only one of the associations would be in use at any time and any other has_many :bookX association that was loaded would be a waste. For example, with a user.id of 2, I'd only need books3.find_by_author('Author'), but the way I'm thinking of setting this up, I'd still have access to Books1..n. I don't really know Ruby/Rails does internally with all of those has_many associations though, so maybe it's not so bad. But right now I'm thinking that it's really wasteful, and that there may just be a better, more efficient way of doing this. So, a few questions: 1) Is there's some sort of special Ruby/Rails methodology that could be applied to this 'multiple tables to represent one entity' scheme? Are there any 'best practices' for this? 2) Is it really bad to have so many unused has_many associations for each object? Is there a better way to do this? 3) Does anyone have any advice on how to abstract the fact that there's multiple book tables behind a single books model/class? For example, so I can call books.find_by_author('Author') instead of books3.find_by_author('Author'). Thank you!

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  • How to save many to many fields by using an auto complete text box

    - by iHeartDucks
    If I have two models like class Author(models.Model): name = models.CharField(max_length=100) title = models.CharField(max_length=3, choices=TITLE_CHOICES) birth_date = models.DateField(blank=True, null=True) def __unicode__(self): return self.name class Book(models.Model): name = models.CharField(max_length=100) authors = models.ManyToManyField(Author) I can render the book form using a model form like this class BookForm(ModelForm): class Meta: model = Book widgets = { 'authors' : TextInput() } The authors fields is now rendered as a text box and I want to use an auto complete (where I can enter multiple authors) text box to populate the field. I am having a hard time to understand how I can save the authors in view function? I am thinking of using a hidden field to record all the author id's but I am having a hard time figuring out how to save it on the postback.

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  • Qt - drag and drop with graphics view framework

    - by David Davidson
    I'm trying to make a simple draggable item using the graphics framework. Here's the code for what I did so far: Widget class: class Widget : public QWidget { Q_OBJECT public: Widget(QWidget *parent = 0); ~Widget(); }; Widget::Widget(QWidget *parent) : QWidget(parent) { DragScene *scene = new DragScene(); DragView *view = new DragView(); QHBoxLayout *layout = new QHBoxLayout(); DragItem *item = new DragItem(); view->setAcceptDrops(true); scene->addItem(item); view->setScene(scene); layout->addWidget(view); this->setLayout(layout); } Widget::~Widget() { } DragView class: class DragView : public QGraphicsView { public: DragView(QWidget *parent = 0); }; DragView::DragView(QWidget *parent) : QGraphicsView(parent) { setRenderHints(QPainter::Antialiasing); } DragScene class: class DragScene : public QGraphicsScene { public: DragScene(QObject* parent = 0); protected: void dragEnterEvent(QGraphicsSceneDragDropEvent *event); void dragMoveEvent(QGraphicsSceneDragDropEvent *event); void dragLeaveEvent(QGraphicsSceneDragDropEvent *event); void dropEvent(QGraphicsSceneDragDropEvent *event); }; DragScene::DragScene(QObject* parent) : QGraphicsScene(parent) { } void DragScene::dragEnterEvent(QGraphicsSceneDragDropEvent *event){ } void DragScene::dragMoveEvent(QGraphicsSceneDragDropEvent *event){ } void DragScene::dragLeaveEvent(QGraphicsSceneDragDropEvent *event){ } void DragScene::dropEvent(QGraphicsSceneDragDropEvent *event){ qDebug() << event->pos(); event->acceptProposedAction(); DragItem *item = new DragItem(); this->addItem(item); item->setPos(event->pos()); } DragItem class: class DragItem : public QGraphicsItem { public: DragItem(QGraphicsItem *parent = 0); QRectF boundingRect() const; void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0); protected: void mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event); void mouseMoveEvent(QGraphicsSceneMouseEvent *event); void mousePressEvent(QGraphicsSceneMouseEvent *event); void mouseReleaseEvent(QGraphicsSceneMouseEvent *event); }; DragItem::DragItem(QGraphicsItem *parent) : QGraphicsItem(parent) { setFlag(QGraphicsItem::ItemIsMovable); } QRectF DragItem::boundingRect() const{ const QPointF *p0 = new QPointF(-10,-10); const QPointF *p1 = new QPointF(10,10); return QRectF(*p0,*p1); } void DragItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget){ if(painter == 0) painter = new QPainter(); painter->drawEllipse(QPoint(0,0),10,10); } void DragItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event){ } void DragItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event){ } void DragItem::mousePressEvent(QGraphicsSceneMouseEvent *event){ QMimeData* mime = new QMimeData(); QDrag* drag = new QDrag(event->widget()); drag->setMimeData(mime); drag->exec(); } void DragItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event){ } main.cpp instantiates a Widget and shows it. When I try to drag the circle, the app just creates another circle over the original one, regardless of where I release the drag. qDebug() in DragScene's dropEvent() shows QPointF(0,0) everytime the drag ends. I'm having a hard time trying to understand exactly what I have to do, which classes I should subclass, which methods needs to be overriden, to make this work. The documentation on this isn't very detailed. I'd like to know how to make this work, and if there's some other, more comprehensive resource to learn about the graphics view framework, besides the official documentation (which is excellent btw, but it would be great if there was a more detailed treatise on the subject). EDIT: Following badgerr's advice, I replaced item-pos() in DragScene::dropEvent() with item-scenePos(), now the drop event creates a new circle in the drop site, which is more or less what I wanted. But the original circle is still in place, and while the drag is in progress, the item doesn't follow the mouse cursor. The QGraphicsSceneDragDropEvent documentation says that pos() should return the cursor position in relation to the view that sent the event, which, unless I got it wrong, shouldn't be (0,0) all the time. Weird. I've read in a forum post that you can use QDrag::setPixMap() to show something during the drag, and in examples I've seen pictures being set as pixmaps, but how do I make the pixmap just like the graphics item I'm supposed to be dragging?

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  • Content display problems when using Suckerfish menus with 960.gs and IE

    - by Cedar Jensen
    I'm using 960.gs layout and when I add the suckerfish menu as part of the content to one of the grids, the contents of adjacent siblings bleed through the menu in all versions of IE. In the listed html below, the text from 'belowFoldSection' will appear through the menu when it is visible and has enough items to make it span over 2nd section. However, the contents of 'introSummary' will be underneath the menu, as expected. I've set the z-index for #nav and #nav ul in my css and this of course makes it work in FF, Chrome and Safari, but not in IE (because IE incorrectly assigns child elements its own z-index). If I change the .grid_nn class 'position' attribute (set by default in the 960 template) from 'relative' to absolute, this fixes it in IE. However, it is my understanding that I don't want the child elements of the 'container_12' to be taken out of the flow of the document and want them positioned relative to the .container_12's starting point. (Changing the attribute to absolute causes other general layout problems) Can anyone suggest a work-around? My html: <div class="container_12"> <!--First section where menu lives--> <div class="grid_12" id="mainSection"> <div class="grid_4 alpha" id="intro"> <p>Start of menu here</p> <div id="subMenu"> <ul id="nav"> <li><a href="#">Item 1</a> <ul> <li><a href="#">Burrowing gobies</a></li> <li><a href="#">Dartfishes</a></li> <li><a href="#">Eellike gobies</a></li> <!--10 more for longer list --> </ul> </li> <li><a href="#">Item 2</a> <ul> <li><a href="#">Remoras</a></li> <li><a href="#">Tilefishes</a></li> <!--10 more for longer list --> </ul> </li> <li><a href="#">Item 3</a> <ul> <li><a href="#">Climbing perches</a></li> <li><a href="#">Labyrinthfishes</a></li> <li><a href="#">Kissing gouramis</a></li> <!--10 more for longer list --> </ul> </li> </ul> <div id="introSummary"> <h1>PERCIFORMES! (1)</h1> <p>Welcome to the world of Perciformes - perch-like fish including the world famous <strong>Suckerfish</strong></p> </div> </div> <!-- end of sub menu --> </div> <div class="grid_8 omega" id="summary"> <p>Some stuff goes here</p </div> </div> <!-- End of first section --> <div class="clear">&nbsp;</div> <div class="grid_12 spacer"> </div> <div class="grid_4" id="belowFoldSection"> <p>Here is some stuff I want to appear below the menu when the pop-up is visible</p> </div> </div> <!-- container_12 --> The suckerfish css file: #nav, #nav ul { /* all lists */ padding: 0; margin: 0; list-style: none; line-height: 1; z-index: 99; } #nav a { display: block; width: 10em; } #nav li { /* all list items */ float: left; width: 10em; } #nav li ul { /* second-level lists */ position: absolute; background: orange; width: 10em; left: -999em; } #nav li:hover ul, #nav li.sfhover ul { /* lists nested under hovered list items */ left: auto; } Default 960.gs css: .container_12, .container_16 { margin-left: auto; margin-right: auto; width: 960px; } .grid_1, .grid_2, .grid_3, .grid_4, .grid_5, .grid_6, .grid_7, .grid_8, .grid_9, .grid_10, .grid_11, .grid_12, .grid_13, .grid_14, .grid_15, .grid_16 { display: inline; float: left; position: relative; margin-left: 10px; margin-right: 10px; }

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  • LINQ 2 SQL: Partial Classes

    - by Refracted Paladin
    I need to set the ConnectionString for my DataContext's based on an AppSetting. I am trying to do this by creating a Partial Class for each DataContext. The below is what I have so far and I am wondering if I am overlooking something? Specifically, am I dealing with my DataContext's correctly(disposing, staleness, etc)? Doing it this way will I have issues with Updates and Inserts? Is the file BLLAspnetdb.cs useful or neccessary in the least or should all of that be in the generated partial class AspnetdbDataContext file? In short, is this an acceptable structure or will this cause me issues as I elaborate it? dbml File Name = Aspnetdb.dbml Partial Class File Name = Aspnetdb.cs partial class AspnetdbDataContext { public static bool IsDisconnectedUser { get { return Convert.ToBoolean(ConfigurationManager.AppSettings["IsDisconnectedUser"]) == true; } } public static AspnetdbDataContext New { get { var cs = IsDisconnectedUser ? Settings.Default.Central_aspnetdbConnectionString : Settings.Default.aspnetdbConnectionString; return new AspnetdbDataContext(cs); } } } My Created File Name = BLLAspnetdb.cs public class BLLAspnetdb { public static IList WorkerList(Guid userID) { var DB = AspnetdbDataContext.New; var workers = from user in DB.tblDemographics where user.UserID == userID select new { user.FirstName, user.LastName, user.Phone }; IList theWorkers = workers.ToList(); return theWorkers; } public static String NurseName(Guid? userID) { var DB = AspnetdbDataContext.New; var nurseName = from demographic in DB.tblDemographics where demographic.UserID == userID select demographic.FirstName +" " + demographic.LastName; return nurseName.SingleOrDefault(); } public static String SocialWorkerName(Guid? userID) { var DB = AspnetdbDataContext.New; var swName = from demographic in DB.tblDemographics where demographic.UserID == userID select demographic.FirstName + " " + demographic.LastName; return swName.SingleOrDefault(); } } see this previous question and the accepted answer for background on how I got to here... switch-connectionstrings-between-local-and-remote-with-linq-to-sql

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  • Axis web service can't be invoked from web application

    - by jani
    Hi all, I have a simple axis 1.4 web service which I deployed successfully and can invoke it from main method of a Java class. This works fine but when I try to invoke it from a web application it throws an exception saying 'Class not found' for the class 'ws/impl/AwardWebServiceSoapBindingStub'. I tried to debug it but could not find anything. Any help? Thanks in advance. Regards, Jani.

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