Inheritance In Classes And Extending Subs ?
Feb 26, 2011
I've been wondering if there is anyway to extend a sub of a base class in a derived class or subclass. To date, the only thing I've been able to find is overrides and overloads functions, but to my understanding these functions just ignore your base class's sub and just allows you to run the new one with the same name.
What I want to be able to do is:
CODE:
I'm not sure whether this is possible, or if I'd simply either make a new sub in my derived class that first ran the base's class sub or whether I'd override the base class and then copy and paste the old code.
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Oct 24, 2009
Here is some example code of what I mean:
vb
Public Class Form1
Private Sub Button1_Click(ByVal sender as Object, e as systemEventArgs) Handles Button1.Click
[Code]....
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Jul 28, 2011
I need to add functionality to my web service calls so object translation and automatic retries are done and abstracted away.I would usually override the base class to add the extra functionality, but as the proxy methods aren't over-ridable I can't keep the method names the same. The only other option I can think of to do it this way is to use the 'Shadows' keyword to achieve what I want.What other methods do people use to add functionality to their web service proxy classes without modifying the generated classes?
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Apr 1, 2010
Briefly, what I'm trying to do is add some methods and properties to the FileInfo class, which is sealed (NotInheritable). As far as I can tell, I have two options to do this.
1) Inherit from FileSystemInfo (the base class for FileInfo) and recreate the methods and properties added by FileInfo (essentially recreating the FileInfo class from scratch)
2) Use extension methods (??) which I just learned about two minutes ago and it being 1am, I'm going to get into this tomorrow
3) Create a wrapper class around a FileInfo object - I think that's the proper term
Ok, so I guess there are 3 options.
A) Why make a class uninheritable
B) Is creating a wrapper class "basically" the same as inheriting from an object, but at least with inheritence you don't need to create any properties and methods other than those you want to modify or add?
Am I correct when I say that a Field is a protected property that can only be accessed by the base class and inherited classes, or is the definition of a field something else?
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Nov 2, 2009
is there anyway we could extend a shared function for a class? example:
<Extension()> Public Shared Function GetName(ByRef e As [Enum], ByVal value As Object) As String
Return [Enum].GetName(e.GetType, value)
[Code].....
however i dun hav a choice as Extension methods can be declared only within modules
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Jun 18, 2010
So in a lot of frameworks there is usually some base type that you tend to extend a lot because well, it is what enables the "visual" aspect of the framework. Here in .Net it's the Control/Form... you tend to be inheriting these frequently for different things, and despite the suggestions otherwise, the team always agrees to extend explicitly and forget about composition.So now say you want to create some relationship between all of these... just a simple interface that uncovers some basic properties that all your forms and controls should have. In this case lets call it 'IProjControl'
Code:
Public Interface IProjControl
Property ProjControlId() As String
[code]....
So this interface is something you expect all your windows and dialog boxes and other some other controls implement. They all don't extend the same exact type, they all just happen to be controls.In there lies the problem... you want to enforce the contract with this interface that not only is it a 'IProjControl', but it's also a 'Control'. But we can't exactly have our interface extend Control (that doesn't make sense), and there isn't an 'IControl' interface to require implementing.
So the method I've always used is something like this:
Code:
Public Interface IProjControl
ReadOnly Property ProjControlComponent() As Control
Property ProjControlId() As String
[code]....
(if there is actually a language/compiler specific feature that allows you to require an interface implementation to be implemented by a class extending a specific type... please, do tell... but I highly doubt there is because for all intensive purposes that sounds weird).
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Mar 1, 2012
I have about 100 websites that I am going to be accessing to scrape some data from (weather, time, etc). When I go to code these babies there will be an abundance of sub routines that I will be creating. They each are going to be accessing pretty much the same type of data.
Should I put them into a Class some how and acces them that way or should I just use Subs and then call them into the Document Completed section of my web browser to run the code? Still sort of confused on the whole Class vs. Sub Routine thing.
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Jun 27, 2011
I am having trouble getting inheritance to work with the VB 2008 Express entity classes. I am a beginner with VB.Net and self-taught in VB6.0.I am able to pull data from an SQL Server data base into my application using the O/R designer. The data can be successfully queried using LINQ to SQL, either returning a single record, or multiple records or an entire table as a collection of the enty class type (so the problem is not with LINQ queries).
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Aug 8, 2011
Background:I have a base class and several inherited derived classes. The derived classes don't always need to have the same properties. If any properties are shared among the derived classes, those properties would live at the base class level ('Contents', for example).Similarly, GoodDocument below has 'GoodThings' but would not want/need to have 'BadThings'.I want to treat instances of both 'GoodDocument' and 'BadDocument' as type 'Document'
public mustinherit class Document
public property Contents as string
public sub new()...
[code]....
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Oct 15, 2011
I am cleaning up some code and I have multiple classes that are 99% exactly the same. So my understanding is that my options are...
1. Create a class and all other classes inherit from it and modify it a bit
2. Create an abstract class and all classes inherit from it and modify a bit ** I took this route
3. Create an interface and all classes Implement that interface.
Here is my 'original' class below (the one that all of them look 99% identical). This class is used in an arraylist so I have a listing of all my images from a folder I have searched.
[Code]...
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Oct 15, 2011
I seem to be having a problem with controls that I am creating as new classes (not UserControls) inheriting from an existing system control. Everything seems ok while I create the control code, through to the compile (which is successful and adds the control to the toolbox) and dragging the control from the toolbox to the GUI surface. However, when I then debug or compile the project, I get a message such
[Code]...
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Jul 27, 2010
I have three classes Employee, Manager and Salesman. Manager and Salesman classes inherits Employee class.
Employee :
Public MustInherit Class Employee
' Field data.
Protected empName As String
Protected empID As Integer
Protected currPay As Single
[CODE]...
Manager :
Public Class Manager
Inherits Employee
[CODE]...
Salesman :
Public Class Salesman
Inherits Employee
[CODE]...
Now I have created a object of salesman and manager using the following code:
Dim objSalesMan as Employee=new Salesman("xyz",1,2000,5000)
Dim objManager as Employee=new Manager("abx",2,5000,"production")
Is this a good programming pratice or should I use:
Dim objSalesMan as new Salesman("xyz",1,2000,5000)
Dim objManager as new Manager("abx",2,5000,"production")
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Jun 15, 2009
I'm trying to call a private sub in another private sub. For example ;
[Code]....
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Oct 26, 2009
When you refrence a Function like this one:[code]You may want to be able to get more out of that, like this.[code]So how would I be able to add subs or functions onto a sub or function like that?
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Jan 23, 2012
I have two classes, one nested in the other. [code]Neither "Name" or "ID" are unique between operations and records.I wish to construct a dictionary using LINQ = Dictionary(Of String, Of List(Of Integer), whereby the keys are uniqe examples of Names in my collection and the values are the collective set of distinct IDs that are associated with those names.
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Jun 13, 2012
How can I structure my classes so that the user interfaces though a single class while the supporting classes are hidden from their view? I think its best understood in an example:
Public Class MyInterface
Public Economic as EconomicClass
Public Sub New()
MyBase.New()
[code].....
So you might ask why am I even separating them? It's strictly for others who will be working with this interface. I need to funnel them though a logical structure:
interface.Economic.MyMethod
interface.Currency.MyMethod
etc
This way everything is already handled for them in the background and they only need to run the method they need. I don't know if I can have it both ways in VB.NET.
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Mar 5, 2010
When you create a webpage in ASP.net, the codebase inherits System.Web.UI.Page Now when I extend the page object to check for SessionExpired for example, I create a new class and inherit from system.web.ui.page, and overwrite some functions. The problem then is that on each page, I have to replace system.web.ui.page with my custompage class. Is there a way to extend a class by adding methods or modifying its methods directly (e.g. add the sessionExpired check to System.Web.UI.Page) ?I'm using .NET 2.0
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Mar 17, 2011
I have a class within a library, with no root namespace, firstone.dll:
namespace first
public partial class one
public sub fun()
[Code]....
Is there a way to extend the class in a separate dll and still have access to the original class? I don't want to inherit the class just extend it.
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Jun 27, 2011
I know from .NET 3.5 onwards (or might be 3.0) we can use Exension Methods to add our own methods to any Type in the .NET Framework and this is very handy, but I'm wondering if it is possible to "extend" an Enum as well?
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Aug 19, 2011
I would like to create a DataGridView that displays records that fill either 18 or 35 columns. I would like to avoid displaying all 35 columns for all records, instead showing the 17 extra columns on a second row for records that need them.How would I go about this? I'm guessing I need to create a new class that inherits from DataGridViewRow and override it's Paint or PaintCells method, but I have no experience with overriding Paint events, so I'm kind of lost after that.
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Jul 30, 2009
I have an class named Foo. This class contains a collection of child objects of type FooChildBase, but I also have a further class of type FooChildTwo which inherits from FooChildBase.
Class Foo
Public Children As IList(Of FooChildBase)
End Class
Class FooChildBase
[code]....
What I would like to do is have my FooSpecial Class treat it's Children collection as if they were FooChildSpecial objects, but still be able to add FooChildTwo objects to it. Is this possible and if so how can it be done?
EDIT:I need to FooChildSpecial class to wrap any of the objects in the Children collection with the extra values, whether they are FooChildBase or FooChildTwo?
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Jan 11, 2010
I am wondering if I can extend a component (e.g a button ) in vb the same way I can in java which enables you to modify the component for your specific requirement or create a new one from scratch.
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Oct 31, 2011
I'm currently using the log4net portion of the Castle Windsor logging facility, like so:
objContainer.AddFacility("logging", New LoggingFacility(LoggerImplementation.Log4net)WithConfig("ConfigsLog4net.config"))
I need to pass in a couple of variables to the logger because I am using dynamic log file names. I have looked at the source code and determined that one possible course of action is to create a custom factory and facility but this is alot of work and I'm not sure it is best practice.
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Jul 10, 2009
I m trying to raise Click event of Textbox explictly but I m getting "Derived classes cannot raise base classes" error.[code]....
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Nov 5, 2010
Is it possible to add a property to the existing asp:BoundField control without creating a brand new instance to which I'd have to declare <tst:BoundField></tst:BoundField>?
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Jan 4, 2010
I have a base class which needs to define an enumeration:
BaseClass
- SomeEnum
I then need to create two derived classes from the base class and extend the values in the enumeration:
ChildClass1 : BaseClass
- SomeEnum
- SomeEnumValue1
[code]....
In C# or VB.NET can someone provide the syntax to do this?
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Nov 26, 2010
As the default for visual studio 2010 is set to ".NET Framework 4 Client Profile" and as such that ill be whats available on the clients PCs. So as i'm looking at adding data binding to a listview headercolumns, i was planning on extending the CollectionEditor (if i have to), but the CollectionEditor is only available when you target the full .NET Framework. So therefore i need to create a second solution with that as a target and build my extended CollectionEditor, but how do i get Studio 2010 (not my 'client' project) to reference my extended CollectionEditor?
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Jan 27, 2010
imagine i want to add an extension method to System.Collections.Generic.List(Of T)
let's say i want to give it .GetUBound which returns Count-1
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Oct 11, 2010
I have to create an XML database for a class I'm taking, but I'm running into some problems. I'm trying to pack my data directly into the DOM using some classes I created and derived from the XMLDocument class, I'm trying to do it this way so I can easily manipulate the entries while the document is in memory and save them back to a file without having to mess around too deeply with the XMLDocument class. I'm running into some problems however when I try to typecast the elements I get from calling
Code:
XMLDocument.DocumentElement.Item
I assume that this is happening due to my derived class not being pushed into the DOM when a file is loaded, because it works just fine if I enter the data manually in code.
Code:
Option Explicit On
[CODE].............
Other than writing my own XMLReader I have no idea how to accomplish this, does anyone have an idea how I could go around doing this(other than writing my own XMLReader).
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Jan 13, 2012
I have a program built on VB.NET and C# . It calls Win32 API and another APIs we made and others (WodSSH and DevExpress).Now we plan to extend our tool to run on Linux and UNIX GUI for UNIX end-users. We have doubts whether to try to import the program somehow (I heard about Mono and Wine) or build it from scratch in Java.
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