Creating Classes And Objects?
Apr 10, 2011
1) Add a Private variable named _area2) Associate the _area variable with a Property procedure called Area3) Change the CalculateArea method to a Sub procedure. The method should calculate the area and then assign the result to the _area variable.4) Include a parameterized constructor in the class. The constructor should accept one argument: the side measurement. After using the Public property to initialize the Private variable, the constructor should automatically call the CalculateArea method.At this point I believe I've completed the first 2 steps for the Square method, but I'm not sure where to go from therHere is my code for the Square class and the Main Form, in tha order:
Public Class Square
Private _side As Integer
Private _area As Integer
[code].....
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Aug 27, 2010
I'm wondering on how you would go abouts instantiating a class that contains other complex objects. for example an Payment Class which has Date,Time, etc.. and it also holds a reference to a paymethod object which has id,Type,Description etc.. How do you instantiate the payment class with all the other objects without one or the other failing, how do you create the payment class which doesn
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Dec 26, 2010
I have a Clients master object and then a number of child objects whose exact number is not known in advance such as Client-Contacts, Client-Payments etc, all of which have a one-to-many relationship with the Client master object.How do I define classes for such a scenario? Do I for instance create the master Clients class and can then I create an array of class somehow for child objects?
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Jan 3, 2012
I have a nested class, let's call it class1 and it has class2 inside it; VB.Net eg:[code]
1) How can I define X number of Class2 objects[let's call it: Node(x) array]** with NEW() subroutine called?' this raises error: dim cls2(n) as new class2 end sub.
2) How can I return actual number of Node() array? [code]Outside my class in main project I define cls1 object:[code]Now an array of class2 is created inside cls1.
3) Now,How can I access All of them[node(x) array which is created inside cls1] with all properties and methods available?
I remember I wrote a ProcessManager class with this functionality in .net 2003, nearly 4 years age, I don't have the code now.
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Aug 29, 2010
The 1st part of the code required me to write a class definition for a class(Worker). The class should include Private variables and Property procedures for a worker object's name and salary.
The salary may contain a decimal place. The class should also contain two constructors:a default and a parameterized.
The second part for the code indicates that I need add a method named GetNewSalary to the Worker class.The method should calculate a Worker objects new salary, which is based on a raise percentage provided by the application using the object.
Before calculating the new salary, the method should verify that the raise percentage is greater than or equal to zero. If the raise percentage is less than zero the method should assign the number zero as the new salary
There are three text boxes which allows the user to enter the employees name current salary and raise percentage....the calculate button will display the new salary in the new salary label box...so far here is what I have for the worker class.
The Class for the code had to be written from scratch. Can you please look over the class code and see if I need to chang anything....that will allow the program to run.[code...]
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Sep 7, 2010
In ASP.NET I have a form that has a Textbox named txtOutput and a button. In the main file.aspx.vb I can call a function from the button handler and in that function I can have [code]I have a bunch of functions in several other classes. For instance I have a class named AbleCommerce that does some database functions. These functions are called from my main class. In those functions, however, I have no visibility of txtOutput.All of my classes are, unfortunately, in the default namespace which I understand is not optimal but didn't seem to impact this issue.
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Dec 28, 2011
suppose I have a collection of objects of different classes (like controls in a form), and all of their classes have a MyMethod extension method. How do I have the appropriatemethod be called for each object, depending on its type?or example,
For Each ctrl In Me.Controls
'call ctrl real type's MyMethod
Next
[code]....
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Mar 5, 2010
Pursuing the Microsoft Certified Professional Developer Certification and working through the training kit.I've programmed for a while and mainly used classes as my objects.The training certification book I'm working through has a section on structures. they look very similiar to classes so my question is: why use them? Do they offer something that creating a class doesn't? What's the difference between structures and classes?
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Jun 5, 2010
I've been trying to understand classes and objects. Yes, I'm thick headed and slow, but I made the decision to go to .Net and I am determined to improve my coding skills to be more efficient. I have spoken to Atma several times on the topic and read most of his posts concerning classes and objects, but still came away a little baffled (He's really advanced for me yet). I needed a simplistic analogy for a reference point to begin understanding. I was reading about OOP written by MikeJ in the following thread/post ...[URL] and it all started to become clear in this statement , but I would like some reassurance that I'm getting it ..."A car IS-A vehicle, while a dog HAS-A tail. The car would be an object declared as type Vehicle, while the dog would have a member that IS-A tail. However, Fido IS-A dog. The dog class is the base template for all dog objects, so when we declare Fido as a dog, Fido is an object. Since Fido IS-A dog, Fido HAS-A tail."
From this I have taken the following understanding...
Vehicle ... ' Class
Car ....... ' Object
Truck ... ' Object
Van ....... ' Object
And from that can I infer that this is true?
Dog ....... ' Class
Fido ... ' Object
Tail .. ' Member of Fido
So to apply this to a program I wrote recently that tracks Generator service...
Generator ' Would be the class
Brand X ' Would be an object
Spark Plug ' Would be a member
Gas Tank ' Would be a member
Brand Y ' Would be an object
Brand Z ' Would be an object
This statement also helped ...
""Class" and "object" are sometimes used interchangeably. However, classes describe the structure of objects, while objects are instances of classes. Each instance is an exact copy of its base class. Because an object is an "instance" of a class, the act of creating an object is called instantiation. To describe it better, a class is a blueprint, and an object is a building based on that blueprint". I can understand this (I think) and it refers to a basic template such as ..."Generator" (my class or blueprint or template) Generators have an engine, powerplant, fuel tank, etc. These are basic requirements to be a generator. (Template or Blueprint) They can differ by Brand of engine, Size of powerplant, and type of fuel used. (Based on template or blueprint) Do I have it down now? MikeJ also made this statement ..."you can't access certain types of class members from outside of the class itself." From this I assume you would need to assign a Global variable the value of the class member if you needed to use it outside of the class?
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Oct 14, 2009
relation between Classes and Objects with an example.Md. Marufuzzaman
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Sep 25, 2011
I have a webservice that is wrapped up by a data access object and is accessed by many different UI controls.
The proxy objects look something like this:
Public Class WebProxyObject1
' Common properties, there are about 10 of these
Public Name As String
[Code]....
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May 9, 2009
I have one class with <Serialize> attribute called Tree. And Tree class has an arraylist of TreeNode classes. Is it possible to use Soap to convert the Tree class and arraylist of TreeNode classes to one xml file or binary file? If it is possible, do i need to use <Serialize> attribute on TreeNode classes too? If not, what should i do then?
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Feb 26, 2010
I have a project where a email is sent when the user clicks send on the web page, however the content of the email will change depending on what is inputted by the user. I have added classes to my project so that depending what is selected by the user different classes are selected and as such different emails then sent from the project.
[Code]...
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Jul 2, 2009
I have a VB.NET web app that is about 2000 lines of code, contains about 20 different subroutines, and about 50 different functions.Is there an easy way to "rewrite" this to take advantage of classes and objects?
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May 18, 2010
This probably sounds daft, but im struggling to get to grips with Classes/Modules/arrays and objects, as well as there uses and what they are, and yes im still coding some how i hear you cry.The reason i ask is because Ive got a load of Dim's in my program that are the same giving locations of files and folders and wondered can they be used as a module that i can alter after the program is built, incase of folder locations being wrong or moved, manually correct after install.
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Jun 26, 2010
I want to know what are classes , objects , a namespace , subroutines,functions,methods,properties and differemce betweem byval and byref in your words.
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Apr 14, 2010
How can I dynamically initiate a "new" class?Basically I'm storing references to classes in an array and I want to create and dispose them on demand.
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Feb 6, 2009
How would you create depth code for two classes in visual basic 2008 (like if you wanted to put one picturebox behind another picturebox depending on what each picturebox's depth equals)?[code]I can't get my movement code and the image for the character object to work.
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Aug 15, 2011
I am using the O/R Designer to create entity classes in VB 2010. I am observing different results for different database tables that I can't explain and more importantly, can't replicate the results that I want.Using server explorer, I have dragged a number of tables on the O/R designer surface, thereby creating the entity classes.
I have saved the project and can access the various entity classes in my project code. I first noticed a difference when changes made to object instances from some tables/entity classes appeared to persist while changes made to object instances from other tables/entity classes did not persist. These object instances are created, accessed, and changed using the exact same code patterns except for the object, class and table names.
I have been looking to see if there are any differences between the way in which the entity classes are treated, either in my code, in server explorer, or in the O/R Designer. I cannot find any. The properties of the entity classes indicate that all of the classes use the runtime methods for insert, delete and update. As far as I am aware, I have not knowingly made changes to these methods.
The ONLY difference that I find is in the file NameofClass.designer.vb. This is an automatically generated document. The partial class of those objects that appear to persist changes contains different code from that of other partial classes where changes to objects do not persist.In the declarations section of this partial class, the following lines appear:
<Global.System.Data.Linq.Mapping.TableAttribute(Name:="dbo.OrderofBattle")> _
Partial Public Class OrderofBattle
Implements System.ComponentModel.INotifyPropertyChanging, System.ComponentModel.INotifyPropertyChanged
[code]....
If I am right then I want to enable persistence in my other classes by causing this additional code to be generated for them. But how? why the code for this one class hase been generated differently than for all the others (actually it is this way for 2 out of about 15 classes). What setting or or selection do I have to make to enable this code to be created for my other entity classes during the automated process?
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Mar 27, 2009
I am learningCreating LINQ to SQL Classes: Using the O/R Designer, the link is found below[url]...But when I Step #8 of Binding Controls on a Windows Form to Entity Classes says:8. Create an event handler for the Form_Load event by double-clicking the form. Add the following code to the event handler:
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Nov 18, 2009
1. Write a Visual Basic Console Application which creates two DateTime objects. One DateTime object should be used to store a value for date purchased. The second DateTime object should be used to store a value for date paid. See below for more information.
2. Assign values to the two DateTime objects.
3. Use the toString method to display the two DateTime objects.
4. Compare the two dates to determine which date occurred first.
5. Compute the number of days elapsed between the two dates.
6. If the date purchased occurred before the date paid, display: The number of days required to receive payment was ________. Replace the _________ with the number of days computed between the two dates.
On the other hand, if the date paid occurred before the date purchased, display: The number of days this order was pre-paid was _______. Replace the _________ with the number of days computed between the two dates.
If the two dates are identical, display: The payment was received on the same date as the purchase.
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Jul 25, 2011
I'm having a problem at the moment developing my application. What i need to do is find out how many modems they are connected to my system and send data to each one in turn. I have the programme working for one modem at the moment.
So I can send data to a modem that i specify, for example a modem on COM port 1. I have functions already that will give me a list of COM ports that I need to open.My problem is that i want to dynamically create a new modem object along side existing modems and store them in a collection.
[Code]...
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Oct 4, 2010
I have a question. I have a class of Cars that I need to display in a simpli-ish string if they will be sold or not base on their number.
[Code]...
I'd like to display a simple string like this:Cars to be sold: 1, 3-5, 7-8, 11, which is based of the .Sell value.Is there some kind of heuristic to create this kind of string in .NET or is it just a bunch of for/each and if/then and redimming of arrays?
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Jun 9, 2011
I have decided I would start small and make a program that would create a "receipt" list in a listbox and a total. Now, I would like the user to be able to add their own "menu" items. I'm assuming the best way to go about this would be to have them actually add it to a database and then a function in the program will refresh the dataset with the new list. However, this is where my problem lies. How can I tell VB .net 2010 that I want to create a new button (or buttons) on the fly, in an orderly pattern on the form, based on the input from a DB?
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Mar 17, 2009
I would like to dynamically create an object (in my case a thread) and then be able reference that object. Simplistically put, I would like to read from a text file and then process each item using a thread (so that I don't have to wait for each item before starting the next). The problem is that I cannot think of a way to create a new thread dynamically ie. thread name so that I can then wait for all created threads before doing something else.
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Mar 28, 2009
Is there a way to dynamically create an object at runtime?Background: Basically i have an employee class that i want to instantiate every time an employee logs in. What i don't want it to have an employee object already created for every employee, but when they log in the object gets created.
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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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Dec 16, 2011
Im considering making my own command line interface with custom commands etc. I was thinking the following objects would be sufficient:
Textbox - for input
Rich text box - for showing processes and output
Button - to insert input
If it can be done, how can I provide line breaks in the output on the rich textbox e.g.
line1: input instruction
Line2: <cp><textfile.txt>
Line3: I/O error, file not found, check file root.
My version of CLI will have no integration with the windows CMD.
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Jan 19, 2009
I am having trouble assigning values to the properties defined in the mock objects.
Public Interface IAddCustomerView
Property FirstName() As String
Property LastName() As String
Property Message() As String
End Interface
My unit test below always fails saying that getMessage was never called:
<Test()> _
Public Sub Should_Display_A_Success_Message()
_presenter = New AddCustomerPresenter(_view, _repositoryStub)
[code]....
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Jun 21, 2010
I'm using VB.NET (visual studio) to create a chatbox (a program that mimics a human and has a text converstion with you). Two of my main classes are a word class and a sentence class. The sentence object is basically going to be a linked list of words objects. As the program executes, many word objects will be instantiated, and so will many sentence objects. But, each class (used to create the object) has several constants, procedures, and functions defined.
For each object instantiated, are new copies of the constants, procedures, and functions created in memory? Or, is only one copy of the constants and procedures created? Since many many objects will be created during program execution (each word of a sentence will be an object), that if the constants/procedures/functions are defined in memory again and again, that I'll run out of memory. What is the best way to structure my program so that the objects created contain only the variable data, and the constants/procedures/functions are defined only once?
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