Search Results

Search found 5007 results on 201 pages for 'django inheritance'.

Page 129/201 | < Previous Page | 125 126 127 128 129 130 131 132 133 134 135 136  | Next Page >

  • Unresolved symbol when inheriting interface

    - by LeopardSkinPillBoxHat
    It's late at night here and I'm going crazy trying to solve a linker error. If I have the following abstract interface: class IArpPacketBuilder { public: IArpPacketBuilder(const DslPortId& aPortId); virtual ~IArpPacketBuilder(); // Other abstract (pure virtual methods) here... }; and I instantiate it like this: class DummyArpPacketBuilder : public IArpPacketBuilder { public: DummyArpPacketBuilder(const DslPortId& aPortId) : IArpPacketBuilder(aPortId) {} ~DummyArpPacketBuilder() {} }; why am I getting the following error when linking? Unresolved symbol references: IArpPacketBuilder::IArpPacketBuilder(DslPortId const&): ppc603_vxworks/_arpPacketQueue.o IArpPacketBuilder::~IArpPacketBuilder(): ppc603_vxworks/_arpPacketQueue.o typeinfo for IArpPacketBuilder: ppc603_vxworks/_arpPacketQueue.o *** Error code 1 IArpPacketBuilder is an abstract interface, so as long as I define the constructors and destructions in the concrete (derived) interface, I should be fine, no? Well it appears not.

    Read the article

  • How can I bind events to strongly typed datasets of different types?

    My application contains several forms which consist of a strongly typed datagridview, a strongly typed bindingsource, and a strongly typed table adapter. I am using some code in each form to update the database whenever the user leaves the current row, shifts focus away from the datagrid or the form, or closes the form. This code is the same in each case, so I want to make a subclass of form, from which all of these forms can inherit. But the strongly typed data objects all inherit from component, which doesn't expose the events I want to bind to or the methods I want to invoke. The only way I can see of gaining access to the events is to use: Type(string Name).GetEvent(string EventName).AddEventHandler(object Target,Delegate Handler) Similarly, I want to call the Update method of the strongly typed table adapter, and am using Type(string Name).GetMethod(String name, Type[] params).Invoke(object target, object[] params). It works ok, but it seems very heavy handed. Is there a better way? Here is my code for the main class: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; using System.ComponentModel; namespace MyApplication { public class AutoSaveDataGridForm: Form { private DataRow PreviousRow; public Component Adapter { private get; set; } private Component dataGridView; public Component DataGridView { private get { return dataGridView; } set { dataGridView = value; Type t = dataGridView.GetType(); t.GetEvent("Leave").AddEventHandler(dataGridView, new EventHandler(DataGridView_Leave)); } } private Component bindingSource; public Component BindingSource { private get { return bindingSource; } set { bindingSource = value; Type t = bindingSource.GetType(); t.GetEvent("PositionChanged").AddEventHandler(bindingSource, new EventHandler(BindingSource_PositionChanged)); } } protected void Save() { if (PreviousRow != null && PreviousRow.RowState != DataRowState.Unchanged) { Type t = Adapter.GetType(); t.GetMethod("Update", new Type[] { typeof(DataRow[]) }).Invoke(Adapter, new object[] { new DataRow[] { PreviousRow } }); } } private void BindingSource_PositionChanged(object sender, EventArgs e) { BindingSource bindingSource = sender as BindingSource; DataRowView CurrentRowView = bindingSource.Current as DataRowView; DataRow CurrentRow = CurrentRowView.Row; if (PreviousRow != null && PreviousRow != CurrentRow) { Save(); } PreviousRow = CurrentRow; } private void InitializeComponent() { this.SuspendLayout(); // // AutoSaveDataGridForm // this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.AutoSaveDataGridForm_FormClosed); this.Leave += new System.EventHandler(this.AutoSaveDataGridForm_Leave); this.ResumeLayout(false); } private void DataGridView_Leave(object sender, EventArgs e) { Save(); } private void AutoSaveDataGridForm_FormClosed(object sender, FormClosedEventArgs e) { Save(); } private void AutoSaveDataGridForm_Leave(object sender, EventArgs e) { Save(); } } } And here is a (partial) form which implements it: public partial class FileTypesInherited :AutoSaveDataGridForm { public FileTypesInherited() { InitializeComponent(); } private void FileTypesInherited_Load(object sender, EventArgs e) { // TODO: This line of code loads data into the 'sharedFoldersInformationV2DataSet.tblFileTypes' table. You can move, or remove it, as needed. this.tblFileTypesTableAdapter.Fill(this.sharedFoldersInformationV2DataSet.tblFileTypes); this.BindingSource = tblFileTypesBindingSource; this.Adapter = tblFileTypesTableAdapter; this.DataGridView = tblFileTypesDataGridView; } }

    Read the article

  • How to prevent Visual Studio setting my default font sizes in an inherited control

    - by Colin
    I have a base class for all my textboxes and I want to set the default font in that class. So I started with this: public partial class MyTextBox : TextBox { public WmlTextBox() { InitializeComponent(); //Font for the whole application can be altered in the Appearance class Font = new Appearance().TextBoxFont; } } I then stripped out all the code in the form that was setting the font of the textboxes. Of course this worked fine until I altered an item on the page. Visual Studio picked up the default font for the application (set in the Appearance class), and generated code in the designer for all TextBoxes to set it to that specific font. How can I stop visual studio from generating code from my default font? I want to allow the developers to change the property, but I want to set the default font centrally.

    Read the article

  • Base class pointer vs inherited class pointer?

    - by Goose Bumper
    Suppose I have a class Dog that inherits from a class Animal. What is the difference between these two lines of code? Animal *a = new Dog(); Dog *d = new Dog(); In one, the pointer is for the base class, and in the other, the pointer is for the derived class. But when would this distinction become important? For polymorphism, either one would work exactly the same, right?

    Read the article

  • Why i can not acces the protected properties in my web application

    - by GigaPr
    Hi i have a web application which has a Base class in which i define all the properties common to the web pages. The base class extends System.Web.UI.Page Furthermore i have a Base User control class where are defined all the properties common to the user controls. the Base User Control extends System.Web.UI.UserControl all the properties in both base classes are protected. All the web pages extends the base class . All the controls extends the base user control class. The problem is i can not access the properties defined in the base class from the user controls and I can not extend two classes in the base user controls The question is how can i access the properties defined in the Base class from within the user controls? I hope i have been clear Thanks

    Read the article

  • Is there a way to automaticly call all versions of an inherited method?

    - by Eric
    I'm writing a plug-in for a 3D modeling program. I have a custom class that wraps instances of elements in the 3D model, and in turn derives it's properties from the element it wraps. When the element in the model changes I want my class(es) to update their properties based on the new geometry. In the simplified example below. I have classes AbsCurveBasd, Extrusion, and Shell which are all derived from one another. Each of these classes implement a RefreshFromBaseShape() method which updates specific properties based on the current baseShape the class is wrapping. I can call base.RefreshFromBaseShape() in each implementation of RefreshFromBaseShape() to ensure that all the properties are updated. But I'm wondering if there is a better way where I don't have to remember to do this in every implementation of RefershFromBaseShape()? For example because AbsCurveBased does not have a parameterless constructor the code wont even compile unless the constructors call the base class constructors. public abstract class AbsCurveBased { internal Curve baseShape; double Area{get;set;} public AbsCurveBased(Curve baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public virtual void RefreshFromBaseShape() { //sets the Area property from the baseShape } } public class Extrusion : AbsCurveBased { double Volume{get;set;} double Height{get;set;} public Extrusion(Curve baseShape):base(baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public override void RefreshFromBaseShape() { base.RefreshFromBaseShape(); //sets the Volume property based on the area and the height } } public class Shell : Extrusion { double ShellVolume{get;set;} double ShellThickness{get;set;} public Shell(Curve baseShape): base(baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public void RefreshFromBaseShape() { base.RefreshFromBaseShape(); //sets this Shell Volume from the Extrusion properties and ShellThickness property } }

    Read the article

  • AS3: Adding get/set methods to a class via prototype

    - by LiraNuna
    I'm looking for a way to extend a class via prototype by adding a get and set functions. The following code will add a function to the class' prototype: MyClass.prototype.newMethod = function(... args) { }; However I want to add both a get and set functions. I tried: MyClass.prototype.fakeProperty = get function(... args) { }; MyClass.prototype.fakeProperty = set function(... args) { }; But that seem to throw compile errors. Is this even possible? Is there some 'internal' naming convention for get/set functions? I am not looking for answers such as 'create a new class and new get/set functions there'.

    Read the article

  • Inherit static properties in subclass without redeclaration?

    - by David
    Hi, I'm having the same problem as this guy with the application I'm writing right now. The problem is that static properties are not being inherited in subclasses, and so if I use the static:: keyword in my main class, it sets the variable in my main class as well. It works if I redeclare the static variables in my subclass, but I expect to have a large number of static properties and subclasses and wish to avoid code duplication. The top-rated response on the page I linked has a link to a few "workarounds", but it seems to have 404'd. Can anyone lend me some help or perhaps point me in the direction of said workarounds?

    Read the article

  • Static and overriding in Java

    - by Abhishek Jain
    public class B { static int i =1; public static int multiply(int a,int b) { return i; } public int multiply1(int a,int b) { return i; } public static void main(String args[]) { B b = new A(); System.out.println(b.multiply(5,2)); System.out.println(b.multiply1(5,2)); } } class A extends B { static int i =8; public static int multiply(int a,int b) { return 5*i; } public int multiply1(int a,int b) { return 5*i; } } Output: 1 40 Why is it so? Please explain.

    Read the article

  • Passing Derived Class Instances as void* to Generic Callbacks in C++

    - by Matthew Iselin
    This is a bit of an involved problem, so I'll do the best I can to explain what's going on. If I miss something, please tell me so I can clarify. We have a callback system where on one side a module or application provides a "Service" and clients can perform actions with this Service (A very rudimentary IPC, basically). For future reference let's say we have some definitions like so: typedef int (*callback)(void*); // This is NOT in our code, but makes explaining easier. installCallback(string serviceName, callback cb); // Really handled by a proper management system sendMessage(string serviceName, void* arg); // arg = value to pass to callback This works fine for basic types such as structs or builtins. We have an MI structure a bit like this: Device <- Disk <- MyDiskProvider class Disk : public virtual Device class MyDiskProvider : public Disk The provider may be anything from a hardware driver to a bit of glue that handles disk images. The point is that classes inherit Disk. We have a "service" which is to be notified of all new Disks in the system, and this is where things unravel: void diskHandler(void *p) { Disk *pDisk = reinterpret_cast<Disk*>(p); // Uh oh! // Remainder is not important } SomeDiskProvider::initialise() { // Probe hardware, whatever... // Tell the disk system we're here! sendMessage("disk-handler", reinterpret_cast<void*>(this)); // Uh oh! } The problem is, SomeDiskProvider inherits Disk, but the callback handler can't receive that type (as the callback function pointer must be generic). Could RTTI and templates help here? Any suggestions would be greatly appreciated.

    Read the article

  • C#: How to inherit constructors?

    - by Ian Boyd
    Imagine a base class with many constructors and a virtual method public class Foo { ... public Foo() {...} public Foo(int i) {...} ... public virtual void SomethingElse() {...} ... } and now I want to create a descendant class that overrides the virtual method: public class Bar : Foo { public override void SomethingElse() {...} } And another descendant that does some more stuff: public class Bah : Bar { public void DoMoreStuff() {...} } Do I really have to copy all constructors from Foo into Bar and Bah? And then if I change a constructor signature in Foo, do I have to update it in Bar and Bah? Is there no way to inherit constructors? Is there no way to encourage code reuse?

    Read the article

  • Organizing a lot of models that use STI in rails

    - by DavidP6
    I have a scenario where I am going to be creating a large number of models that use STI and I'm wondering what the best way to organize this is. I already have other models using STI and I really do not want to add any more files to my models folder. Is there any way to create a folder and add the models using STI there (there could be upwards of 40 b/c each uses its own methods to scrape a different site, but they all save the same data)? This seems like it would be best, or I could add them all to one file but I would rather separate them.

    Read the article

  • Why is F# member not found when used in subclass

    - by James Black
    I have a base type that I want to inherit from, for all my DAO objects, but this member gets the error further down about not being defined: type BaseDAO() = member v.ExecNonQuery2(conn)(sqlStr) = let comm = new MySqlCommand(sqlStr, conn, CommandTimeout = 10) comm.ExecuteNonQuery |> ignore comm.Dispose |> ignore I inherit in this type: type CreateDatabase() = inherit BaseDAO() member private self.createDatabase(conn) = self.ExecNonQuery2 conn "DROP DATABASE IF EXISTS restaurant" This is what I see when my script runs in the interactive shell: --> Referenced 'C:\Program Files\MySQL\MySQL Connector Net 6.2.3\Assemblies\MySql.Data.dll' [Loading C:\Users\jblack\Documents\Visual Studio 2010\Projects\RestaurantService\RestaurantDAO\BaseDAO.fs] namespace FSI_0106.RestaurantServiceDAO type BaseDAO = class new : unit -> BaseDAO member ExecNonQuery2 : conn:MySql.Data.MySqlClient.MySqlConnection -> sqlStr:string -> unit member execNonQuery : sqlStr:string -> unit member execQuery : sqlStr:string * selectFunc:(MySql.Data.MySqlClient.MySqlDataReader -> 'a list) -> 'a list member f : x:obj -> string member Conn : MySql.Data.MySqlClient.MySqlConnection end [Loading C:\Users\jblack\Documents\Visual Studio 2010\Projects\RestaurantService\RestaurantDAO\CreateDatabase.fs] C:\Users\jblack\Documents\Visual Studio 2010\Projects\RestaurantService\RestaurantDAO\CreateDatabase.fs(56,14): error FS0039: The field, constructor or member 'ExecNonQuery2' is not defined I am curious what I am doing wrong. I have tried not inheriting, and just instantiating the BaseDAO type in the function, but I get the same error. I started on this path because I had a property that had the same error, so it seems there may be a problem with how I am defining my BaseDAO type, but it compiles with no error, which further confuses me about this problem.

    Read the article

  • XML Schema for a .NET type that inherits and implements

    - by John Ruiz
    Hi, Please consider the following three .NET types: I have an interface, an abstract class, and a concrete class. My question is how to write the XML Schema to include the properties from the interface and from the abstract class. public interface IStartable { bool RequiresKey { get; set; } void Start(object key); } public abstract class Vehicle { uint WheelCount { get; set; } } public class Car : Vehicle, IStartable { public bool RequiresKey { get; set; } public string Make { get; set; } publilc string Model { get; set; } public Car() {} public void Start(object key) { // start car with key } } I don't know how to complete this schema: <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="cars" xmlns="cars" xmlns:c="cars"> <!-- How do I get car to have vehicle's wheelcount AND IStartable's RequiresKey? --> <xs:element name="Car" type="c:Car" /> <xs:complexType name="Car"> <xs:complexContent> <xs:extension base="c:Vehicle"> <xs:group ref=c:CarGroup" /> </xs:extension> </xs:complexContent> </xs:complexType> <xs:group name="CarGroup"> <xs:sequence> <xs:element name="Make" type="xs:token" /> <xs:element name="Model" type="xs:token" /> </xs:sequence> </xs:group> <xs:complexType name="Vehicle"> <xs:sequence> <xs:element name="WheelCount" type="xs:unsignedInt" /> </xs:sequence> </xs:complexType> <xs:complexType name="IStartable"> <xs:sequence> <xs:element name="RequiresKey" type="xs:boolean" /> </xs:sequence> </xs:complexType> </xs:schema>

    Read the article

  • method __getattr__ is not inherited from parent class

    - by ??????
    Trying to subclass mechanize.Browser class: from mechanize import Browser class LLManager(Browser, object): IS_AUTHORIZED = False def __init__(self, login = "", passw = "", *args, **kwargs): super(LLManager, self).__init__(*args, **kwargs) self.set_handle_robots(False) But when I make something like this: lm["Widget[LinksList]_link_1_title"] = anc then I get an error: Traceback (most recent call last): File "<pyshell#8>", line 1, in <module> lm["Widget[LinksList]_link_1_title"] = anc TypeError: 'LLManager' object does not support item assignment Browser class have overridden method __getattr__ as shown: def __getattr__(self, name): # pass through _form.HTMLForm methods and attributes form = self.__dict__.get("form") if form is None: raise AttributeError( "%s instance has no attribute %s (perhaps you forgot to " ".select_form()?)" % (self.__class__, name)) return getattr(form, name) Why my class or instance don't get this method as in parent class?

    Read the article

  • accessing base class's method with derived class's object which has a method of same name.

    - by ashish yadav
    when accessing foo() of "base" using derived class's object. include class base { public: void foo() { std::cout<<"\nHello from foo\n"; } }; class derived : public base { public: void foo(int k) { std::cout<<"\nHello from foo with value = "< } how to access base class method having a method of same name in derived class. the error generated has been shown. i apologize if i am not clear but i feel i have made myself clear as water. thanks in advance.

    Read the article

  • Calling Subclass Method in Java

    - by destructo_gold
    Given the following situation (UML below), If Y has the method: public void PrintWs(); and X has: ArrayList <P> myPs = new ArrayList(); Y y = new Y(); Z z = new Z(); myPs.add(y); myPs.add(z); How do I loop through each myPs object and call all Ys PrintWs (without using instanceof)? http://starbucks.mirror.waffleimages.com/files/68/68c26b815e913acd00307bf27bde534c0f1f8bfb.jpg

    Read the article

  • Access static class variable of parent class in Python

    - by fuenfundachtzig
    I have someting like this class A: __a = 0 def __init__(self): A.__a = A.__a + 1 def a(self): return A.__a class B(A): def __init__(self): # how can I access / modify A.__a here? A.__a = A.__a + 1 # does not work def a(self): return A.__a Can I access the __astatic variable in B? It's possible writing a instead of __a, is this the only way? (I guess the answer might be rather short: yes :)

    Read the article

  • C# Hiding, overriding and calling function from base class.

    - by Lukasz Lysik
    I'm learning C# and I encountered the following problem. I have two classes: base and derived: class MyBase { public void MyMethod() { Console.WriteLine("MyBase::MyMethod()"); } } class MyDerived: MyBase { public void MyMethod() { Console.WriteLine("MyDerived::MyMethod()"); } } For now, without virtual and override key words. When I compile this I get the warning (which is of course expected) that I try to hide MyMethod from MyBase class. What I want to do is to call the method from the base class having an instance of derived class. I do this like this: MyDerived myDerived = new MyDerived(); ((MyBase)myDerived).MyMethod(); It works fine when I do not specify any virtual, etc. keywords in the methods. I tried to put combination of the keywords and I got the following results: | MyBase::MyMethod | MyDerived::MyMethod | Result printed on the console | | -----------------|---------------------|-------------------------------| | - | - | MyBase::MyMethod() | | - | new | MyBase::MyMethod() | | virtual | new | MyBase::MyMethod() | | virtual | override | MyDerived::MyMethod() | I hope the table is clear to you. I have two questions: Is it the correct way to call the function from the base class (((MyBase)myDerived).MyMethod();)? I know about base keyword, but it can be called only from the inside of the derived class. Is it right? Why in the last case (with virtual and override modifiers) the method which was called came from the derived class? Would you please explain that?

    Read the article

  • How to inherit events between objects

    - by marduck19
    I need inherit events and properties for example move a picture around the form Y have this code to move the picture but y need create multiple images with the same behavior private void pictureBox_MouseDown(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { x = e.X; y = e.Y; } } private void pictureBox_MouseMove(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { pictureBox.Left += (e.X -x); pictureBox.Top += (e.Y - y); } }

    Read the article

  • Returning a C++ reference in a const member functionasses

    - by Chris Kaminski
    A have a class hierarchy that looks somethign like this: class AbstractDataType { public: virtual int getInfo() = 0; }; class DataType: public AbstractDataType { public: virtual int getInfo() { }; } class Accessor { DataType data; public: const AbstractDataType& getData() const { return(data); } } Well, GCC 4.4 reports: In member function ‘const AbstractDataType& Accessor::getData() const’: error: invalid initialization of reference of type ‘const AbstractDataType&’ from expression of type ‘const DataType’ Where am I going wrong - is this a case where I MUST use a pointer?

    Read the article

  • Python: how to inherite and override

    - by Guy
    Consider this situation: I get an object of type A which has the function f. I.e: class A: def f(): print 'in f' def h(): print 'in h' and I get an instance of this class but I want to override the f function but save the rest of the functionality of A. So what I was thinking was something of the sort: class B(A): .... def f(): print 'in B->f' and the usage would be: def main(a): b = B(a) b.f() #prints "in B->f" b.h() #print "in h" How do you do such a thing?

    Read the article

  • Ruby get inheriting class

    - by Brian D.
    I'm working on creating my first plugin for rails. I'm still pretty new to ruby and I was wondering if its possible to get the inheriting class? For example, I'm trying to create a plugin that will allow unit testing and functional testing when you are not using migrations. What I'm trying to do is initialize a class variable named controller to be initialized to the type of controller that is being tested. If I have a base class ControllerTest: class ControllerTest < Test::Unit::TestCase attr_accessor :controller def initialize super @controller = "call function that will find the inheriting classes name and create an instance of that controller type." end end So what I'm currently stuck on is getting the name of the inheriting class. Is this possible? And if not, does anyone know another way on how I could go about implementing this? Thanks in advance.

    Read the article

  • Qt - invalid conversion to child class

    - by David Davidson
    I'm drawing polygons using the Graphics View framework. I added a polygon to the scene with this: QGraphicsPolygonItem *poly = scene->addPolygon(QPolygonF(vector_of_QPointF)); poly->setPos(some_point); But I need to implement some custom behaviour like selection, mouse over indicator, and other similar stuff on the graphics item. So I declared a class that inherits QGraphicsPolygonItem: #include <QGraphicsPolygonItem> class GridHex : public QGraphicsPolygonItem { public: GridHex(QGraphicsItem* parent = 0); }; GridHex::GridHex(QGraphicsItem* parent) : QGraphicsPolygonItem(parent) { } Not doing much with that class so far, as you can see. But shouldn't replacing QGraphicsPolygonItem with my GridHex class? This is throwing a " invalid conversion from 'QGraphicsPolygonItem*' to 'GridHex*' " error: GridHex* poly = scene->addPolygon(QPolygonF(vector_of_QPointF)); What am I doing wrong?

    Read the article

  • Maven: trying to get my submodule's poms to NOT inherit a plugin in the parent

    - by jobrahms
    My project has a parent pom and several submodule poms. I've put a plugin in the parent that is responsible for building our installer distributables (using install4j). It doesn't make sense to have this plugin run on the submodules, so I've put false in the plugin's config, as seen below. The problem is, when I run mvn clean install install4j:compile it cleans, compiles, and runs the install4j plugin on the parent, but then it tries to run it on the child modules and crashes. Here's the plugin config <plugin> <groupId>com.google.code.maven-install4j</groupId> <artifactId>maven-install4j-plugin</artifactId> <version>0.1.1</version> <inherited>false</inherited> <configuration> <executable>${devenv.install4jc}</executable> <configFile>${basedir}/newinstaller/ehd-demo.install4j</configFile> <releaseId>${project.version}</releaseId> <attach>false</attach> <skipOnMissingExecutable>true</skipOnMissingExecutable> </configuration> </plugin> Am I misunderstanding the purpose of inherited=false? What is the correct way to get this to work? I'm using maven 2.2.0.

    Read the article

< Previous Page | 125 126 127 128 129 130 131 132 133 134 135 136  | Next Page >