Way To Make A Value Accessible Only To Parent Of A Nested Class
Jun 24, 2009
In general, according to the OOP paradigm, my understanding of encapsulation basically says:
-If a member is private, it can only be accessed by the class.
-If a member is protected, it can only be accessed by the base class and any derived classes.
-If a member is public, it can be accessed by anyone.
If I have a nested class, can I declare a property to be accessible only to that class and the parent class it's nested within? For example:[code]In the example, I cannot directly access myNestedObject.myInt or myNestedObject.myDbl from an instance of ContainerClass if those members are Private or Protected. But suppose I don't want to make them Public,because then they are TOO exposed: they can be altered from anywhere, not just within a Container Class object. Declaring them Friend would still be too weak as that would allow them to be altered from anywhere within the application.
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Jun 7, 2012
I want to created a nested class that can only be visible to and instantiated from the parent class.But I also want to be able to use an instance of the nested class through a public variable of the parent class.I tried making the nested class private, or making the nested class' constructor private, but it won't compile.Is it possible to do this in .NET?
[Code]...
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Feb 5, 2011
E.g. I have a class:
Namespace Common
Public Class AClass
Public Class BClass
[code]....
How can I use BClass without saying AClass.BClass, I've see some existing code using this format, but I can't find the setting.
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Jan 1, 2012
I have Class1 and class2 which is inside class1, VB.NET code:
Public Class class1
Public varisbleX As Integer = 1
Public Class class2
[code]....
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Mar 3, 2012
I have a MDI project that has a parent and several children forms. In some of the children forms I would like to make one of the forms to be a parent form with children. On this child form I wanted to make a tabbed MDI, which I can do, but I have found out that I can't make a child form a parent, from what I have found.
Is there any way to get around this? (As in nested MDI forms.)
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Aug 3, 2011
This is a challenging one that got me stumped while I was coding today. Suppose I am running the Sub Test1() and Test2() and would like to print out the value of the Shadows method of the instance of the object I am passing in to TestCall() (see below - it is clearer) using the following restrictions:
Can't change the contents of Class A, B, and C
Can't change Sub Test1() and Sub Test2()
TestCall() can't have an if, select case etc. statement that tries to figure out the type
[code].....
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Jun 24, 2009
I have a main form, and some sub forms, and each sub form can have some sub forms. When I have multiple sub forms open, and I try to get data from the parent form, it returns the data from the wrong parent form.For example I have two instances of Mainform.subform running. If I do something like this in a child form of one instance of the subform. It returns data from the other subform.
dim l = Mainform.subform.listofdata
Edit:I am using visual Studio 2008. Winforms, form designed using designer. In my mainform I am doing this
Protected Friend frmMain as Mainform
frmmain = new mainform
In frmMain I am doing this
Protected Friend frmsub as new Subform'
frmsub = new subform
[code]....
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Feb 15, 2011
I have a class that hosts inside other classes that can host otherclases as well and so on.
I want to change the value of one property (PropertyA) in all classes down the tree.
How can i do that when i dont know the the type of class inside?
How can i iterate through the classes hostes as proeprty of the mother class?
I am trying to use reflection but i get just the properties of the first class
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Feb 28, 2010
I can't understand it..let me show you what i have first :
CODE:
and
CODE:
in ReportsOfficesEntities.vb:
CODE:
in BaseController.vb:
CODE:
And of course i added the references for both projects...
the error in BaseController.vb:
CODE:
I checked the whole code ..wondering if i am missing something ... nothing!
searched -->
1: maybe it is different a littel... i don't know
2:i am not sure if it is the same issue .. and it looks complicated to me..
note: i copy (Convert) that from C#.net project and it is working just fine in (C#.net)....!
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Sep 12, 2009
I am trying to create a Class that is COM accessible.The problem I am having is that I cannot have any arguments in the class constructor Sub New.If I do than I get the error:"MSB3214 does not contain any types that can be registered for COM Interop"I can however afterwards use regasm ComDotNet.dll /tlb to create the tlb file.
However when I try to use the class in VB (after adding the reference) withDim test As ComDotNet.HelloDotNetSet test = New ComDotNet.HelloDotNet("Hello")I get an error.
If I remove the argument from Sub New() everything works fine.
Here is the code:
Code:Imports SystemImports System.Runtime.InteropServices
Public Interface IHelloDotNet Function GetAge() As Integer Sub SayHello()End Interface
[Code].......
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Jul 7, 2011
I'll try to explain this the simplest way I can, and I'll be happy to provide more elaboration as needed.
I've created a class, class playership, as part of a little strategy game for my own practice.
I've created the instance of a playership object in my main form using the following [code]...
I'm a little confused about this because I thought a public object or variable could be accessed from anywhere within a project.
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Nov 26, 2010
I have an issue with FxCop and the warning: Abstract types should not have constructors.This is being displayed for a number of abstract classes (possibly all, I haven't checked). When I look most of them have no new method so I assume it's the complier adding a default one. So to remove it I add a private default constuctor (Private Sub New()), this then means all the inherting classes fail to build with the error: Class 'InheritingClass' has no accessible 'Sub New' and cannot be inherited.This seems odd as FxCop requests no public constructor, but when I remove it the build fails.
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Dec 16, 2009
If Class X is within the scope of Class Y, is X a subclass of Y?If Class A is a sub Class of B, then is Class B considered a super class of A?if Class C inherits Class D is Class D a superclass or parent of Class C?if Class E extends Class F then we can consider Class E a child of F?if Class G inherits Class H and is within the scope of Class I then who is the parent of Class G? Classes that inherits Class J and classes that are within Class J are all sub classes of Class J?
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Apr 19, 2011
I added a serial port com1 to my vb.net form. I created a new class and wrote a method to open the com1 and created its object in the main form and called the method and its opening.THen i created another class wrote a method to write data to the com and same way created an object and called it but i am getting the error as port is closed. What am i doing wrong.
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Apr 19, 2010
How do you make listbox accessible outside the form it is situated on?
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Jun 8, 2011
i am developing a system for a business and would like the server to be one of the computers of the
organisation. My problem is that i don't know how to make the database accessible by the other
machines.
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Dec 30, 2009
I have an issue with an app i am writing, i need to make a variable accessible to any module or class within the project but that cant be accessed outside of the app as it is accessing info the end user shouldn't have access to.
Ok, well a practice i have gotten into in the last few years is to declare a module on the same page as the main form and declare variables either friend or public (global variables). with my app public is not good so i tried Protected Friend but i cant use this within a module.
I tried placing it at the top of the main form but one of my classes can't access it, what would be the right way to do as expected. besides the main form i have 2 classes call them class1 and class2:- main interacts with both classes class1 accesses class2 class2 doesn't access class1
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Oct 21, 2011
How do I make Variable eccessable to other forms in my app?
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Mar 15, 2011
I am using a repeater to build a custom table. However, I can't figure out how to make the table show subtotal if the next rows tour does not match the previous rows.
Something similar to that.
row1 tour1
row2 tour 1
tour1 subtotal
[Code].....
but this shows all the data in the nested repeater not the ones that match the parentrepeater fields for example tour,theme,dep7 should match in the child repeater
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Apr 11, 2009
I have a 'property management class' that contains several functions and properties. I have several other classes that use the 'management class' as a property to derive the value of several of its other properties.Is there a way for me to reference the outer class from the 'management class' functions without having to pass it as a parameter? I ask because several different classes can have this 'management class' as a property and am having a hard time typing the parameter.
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Mar 30, 2010
This is a bit of a continuation from a previous post for which AtmaWeapon was very informative.
Problem:
A parent class has a sub class with various properties. A property of the parent class is a List(of T) with T = the sub class The issue is how to store data in the sub class of the instantiated parent
Some example code (hopefully formatted correctly):
Code:
'=========== Class Definitions =============
Public Class courseClass
Public Class timeTableClass
[Code].....
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Jan 2, 2010
I have a Parent Class Called Fuselage that containsfour child classes called Forebody, CenterBody, AftBody, and CrossSection. CrossSection classcontains objects common to Forebody, CenterBody, and Aftbody (example: width). How do I access thewidth property in CrossSection from within the classForebody?
Public Class Fuselage
Dim Forebody As ClsSection
Dim Centerbody As ClsSection
[code].....
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Oct 17, 2011
I'm just taking over an asp.net/vb site, and I'm definitely still learning. I'm receiving the following error:
BC30451: 'ByOwner' is not declared. It may be inaccessible due to its protection level.
I call a datasource with:
<asp:GridView ID="CaseCountByOwner" runat="server" AllowSorting="true" DataSourceID="ByOwner"
And here's what is in the codefile:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
HitMe.AddHit(Request.UserHostAddress, Request.UserAgent, Request.Url.ToString)
Dim user As String = Request.QueryString("user")
If user.Length() = 0 Then
[Code] .....
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Nov 28, 2009
I have a RadioButtonList control which triggers a Sub LegalGaps on SelectedItemChanged event. This Sub creates and fills in an array the size of which depends on the User's choice of radiobutton options. The second Sub AvailableDays shall be able to read that array and highlight the days in the Calendar control accordingly on DayRender event. May I somehow declare an internally created variable a public one?
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Feb 10, 2009
assume that i have two forms(form1 and form2)form1 code
Imports System.IO
Public Class Form1
Inherits System.Windows.Forms.Form
[Code]....
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Feb 10, 2010
So I am making kinda of wizard, with options and a next buttons all in the same form but using hide and show.I have 3 of them. How can I make variables accessible to the entire form?
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Feb 10, 2012
I created a DB using following code.
Dim conn As New SqlConnection("Server=.SQLExpress;Data Source=;Integrated Security=SSPI")
Dim cmd As New SqlCommand("", conn)
cmd.CommandText = "CREATE DATABASE MyDBTest22 ON ( FILENAME = 'D:dbTestATTTTTTT.mdf' ), ( FILENAME = 'D:dbTestATTTTTTT_log.ldf' ) FOR ATTACH"
[code]....
It ran without any error but when I opened SSMS, I could not see my file attached to the server. Also, I tried to make a connection, but it says file does not exist but when I tried to re-run the above code, it says File already exists.Something wrong with my way of doing it? I want to see it attached with the instance of my SQL Server Express 2005, using SSMS.
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Apr 23, 2012
I have a Public Class called "ClientConnection". Inside that class, I have a Public ReadOnly Property called "FileTransfers(ByVal TransferID)". The property returns an object of the class "FileTransfer". All methods in FileTransfer are set to public.
VS is able to discover the methods inside the parent class "ClientConnection". How would I expose the methods inside the sub-class "FileTransfer" that is returned by the property "FileTransfers(ByVal TransferID)"?
Public Class ClientConnection
'irreverent code removed
Public ReadOnly Property FileTransfers(ByVal TransferID As Integer)
[Code].....
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Jan 20, 2011
I am trying to figure out the best approach for setting and getting properties in a nested class I am creating. I have a class, Car which has a nested class ControlPanel and want to make the properties of the Control Panel only accessible to the Car and Control Panel class.
[Code]...
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Mar 31, 2012
I have a problem that is frustrating me to no end, I have a overrideable function in a parent class, and the override function in the child class, like below:
[Code]...
When i debug, the value is produced, but it doesn't carry over to the parent class of ski.RetailPrice()what seems to be the problem here?
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