Can you define this :
Class
Object
Inheritance
Polymorphism
Abstraction
And could you make it easy to understand I'm having a hard time to understand those terms.
I wasn't quite sure how to label this but that should cover it all. I am using Linq to Sql classes to query a SQL Server table. That part is working fine. I'd like to add the records to a listbox and not just text. I can do this and it works. To get it to display something meaningful in the listbox, I have to override the ToString() function.
So, I've taken the base class tblVendor and created a new sub class tblVendorListObject that inherits tblVendor and overrides ToString to return Me.vendorName. I then use a foreach loop to iterate through the records returned by the query. Next, I create a new instance of tblVendorListObject and attempt to assign the current item in the foreach loop to it.
[Code]...
If we are within the derived class then ofcource we can use MyBase keyword to access base class's object reference . That's fine , how can we take that base class's object reference outside that derived class's definition.My following code will explain what i want . Actually that is giving error right now, but it is explaining my requirement .
Public Class Base
Public x As String
End Class
[code]....
Actually there is error in ReadOnly Property BaseReference's Getter . Error is "Error 1 'MyBase' must be followed by '.' and an identifier. " how can i get base class object reference in Main method ?
If we are within the derived class then ofcource we can use MyBase keyword to access base class's object reference . That's fine , how can we take that base class's object reference outside that derived class's definition.
My following code will explain what i want . Actually that is giving error right now, but it is explaining my requirement .[code]...
I see a sample code that an object is instantiated within the class definition block. But when I test the folllowing, I got error "Process is terminated due to
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i had a class called Tag with a structure like:
public class Tag
private _members
public properties
public shared database_methods
end class
this class was tailored for mysql database. i'm currently adding access 2007 support so i split tag into tag and tagdata with structures like:
[Code]...
I have put this code in the global form Inherits System.Windows.Forms.Form. And then in the form that will inherit this from the global Inherits MenuStrip. "MenuStrip" is what the global form is called. But keep getting this error: Error1Base class 'MenuStrip' specified for class 'Lesson2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types.
View 5 RepliesIn VB.NET, say I have a function Public Function Foo(ByVal currentShape as Shape) Instead up passing in a Shape object, I pass in a subclass of Shape called Square like such: Dim square As Square = new Square() Foo(square). Do I need to convert my Square object to a Shape object before passing it in? If so, how do I do this?
View 4 RepliesI'm trying to create a class for storing data on People with another class to store their Bank Transactions.Ideally, this all be hidden away and leave only simple statments, declarations and functions available to the programmer.[code]I know this is possible as these exist in the Listbox Class though can't figure out how it's done.
View 2 RepliesI have a class definition that I've seen other define properties that return collections of objects.
Public Property GetAllAdults() as Adults End Property I made the argument that this should be a method in the class, because it doesn't define an attribute of the class, and could not be extended with parameters. Is/Are there reasons why this should be defined as a property vs. a function?
How do I creat a simple array of class definitions?[code]...
View 13 RepliesI'm having trouble with the definition of an inherited generic class. I have two base classes that are defined like this:[code]
View 2 RepliesIn the following two code snippets, the code does the same thing, when I tested this.
Dim test As New Class1 Dim test As New Class1() Do the parantheses make a difference in some way? Is there an explanation of this in the msdn library?
I'm working a business layer (separate assembly) that will contain various business entities used in multiple client applications. One of the client applications is a WCF app that will need to serialize these entities. In order to properly serialize the entities, metadata for data contracts or for XML serialization must be added, but the serialization requirements may vary across applications.
Clearly I need the metadata separated from the class definition. So how do I add metadata to my entities for each separate application?
I call upon the VB ninjas out there. Here's my situation. I need to eventually be able to pass multiple models to a view. Currently I have a linq to sql class that, of course, has a bunch of generated model definitions. I need to make a model that implements multiple models. I somewhat understand how to do this in C#, but this project is testing my VB skillz. Here's some snippets from my linq to sql models. I need to combine these two into one model to pass to the view.
[Code]...
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?
In order to organize various methods of my MainForm class, I would like to categorize them into several files. Of course, the methods would still need to access form elements and additional variables I added in the MainForm class.
View 3 RepliesI am currently using reflection to retrieve all properties of a class. I return a collection of PropertyInfo objects and all is working fine.
My problem is, I want to check if a property has been defined in a base class implementation and is therefore inherited in the current class.
I have 3 classes that need themselves in order to do their work but if I declare them the old way it would end up being an endless loop.
As an ex C++ programmer, I know I could use include once but I don't know if there is any equivalency in vb.net Here is the picture.
I have 3 Classes : SQLConnector, ErrorHandler, LogHandler
- ErrorHandler needs SQLConnector to get some IDs from the Database.
- ErrorHandler needs the LogHandler class to prepare the Logs to be... logged.
- SQLConnector needs the ErrorHandler class in case there is errors happening.
- LogHandler needs SQLConnector to insert in the database.
- LogHandler needs ErrorHandler in case the insert is not successful (sends mail in that case)
As you can see, all three classes are needed. The reason why I can't use LogHandler and ErrorHandler as one class is that I will use that class to log transactions and changes according to some parameters. Log is in no way exclusive to ErrorHandler.how I can prevent to make an endless loop and use all three of them as I wish?
In a global module, I define a new type that can take 4 values:
enum tAction as integer
None
Update
Insert
Delete
end enum
A use this type in many places in my code to check the value stored in a variable (if MyAction = tAction.Delete then ...)
In a separate file, I define a class. One of the properties should return a value of this type:
public class XXX
private _Action as tAction
public property ClassAction() as tAction
[Code].....
This way I could check a class property in the same manner (if MyClass.ClassAction = tAction.Insert then ...)
However I get a syntax error in the property definition: 'ClassAction' cannot expose type 'Globals.tAction' outside the project through class 'XXX'
My entire program consists in a few modules, in a single project. How can I use my tAction definition in my classes?
i have a class call it clsFamily this class contains properties that make up a family object. This class works fine with no issues. Now i need a new class (called MyAccount) which contains 3 properties, an ID a user name and a clsFamily object. I have declared both classes as Friend from within my globals Module and define the clsFamily as family, however when i try to put this type within my 2nd class i get an error "Type 'family' is not defined" what am i doing wrong? i know i could get it to work fine by adding the ID and User Name properties to the clsFamily object but i need to define this as a new type of object as the ID and User name are not normally part of this class.
View 12 RepliesI'm trying to return code like this (can be found here):
{"hotspots": [{
"id": "test_1",
"anchor": { "geolocation": { "lat": 52.3729, "lon": 4.93 } },
[code].....
working on an implementation of a list control for a card game. The catch is the deck control object. I want it to be reusable for different types of cards, which is wheretuck since I seem to be having some issues.First: The basic card object
Public Class BaseCard
'Properties
Private _Id As Integer
[code]....
I have two custom objects.On of them inherits the other one, appends few more properties and methods, ovverides some other.When I try to cast the Parnet Object to Child I receive an error that it could`nt be done.
View 1 RepliesI'm running VS2005, and when I right click on an object and select Go to Definition it brings me to the object browser instead of the actual code.Is there some settings that I can change to fix this? Note: it works properly for C# solutions, I am having the problem with Basic.
View 2 RepliesI have a base class which defines a shared readonly property like this[code]...
View 5 RepliesI am developing a windows based application in VS2005. I want all my form to be inherits from one of my class e.g.ParentClass but indeed the windows forms already inherits windows.forms.form class. what I have tried is that, I inherit "windows.forms.form" in "ParentClass" and all forms inherits my "ParentClass". But in this case when I view the design of the form IDE gives error.
View 3 RepliesThe test is base on Visual Basic inheritance, need to create a derived class, and identify the inheritance.
View 5 RepliesI have been learning vb.net for about 6 months now and I red few books about basic visual programming as most to them have information about the basic concepts like what is Object oriented programming, subroutines, functions ,inheritance etc and bit about ADO connectivity to database. Having said all that I think I have good concepts about all these things but now I want to proceed further but can't find appropriate text books or online tutorials.
View 2 RepliesI have to write an inheritance hierarchy for class Quadrilateral, square and rectangle. Use Quadrilateral as base class of the hierarchy.
So for I had this:
Public MustInherit Class Quadrilateral
Public Function getName() As String
Return "Shape"
End Function