Public Class Class1
Private names As List(Of String)
Private _class2 As New Class2
Public Sub AddName(ByVal name As String)
names.Add(name)
_class2.Add()
End Sub
Public ReadOnly Property AddAge(ByVal name As String) As Class2
Get
_class2.index = names.IndexOf(name)
Return _class2
End Get
End Property
Public Sub Clear()
names.Clear()
_class2.Clear()
End Sub
Public Class Class2
Private _age As List(Of Integer)
Protected Friend index As Integer
Public Property Age() As Integer
Get
Return _age(index)
End Get
Set(ByVal value As Integer)
_age(index) = value
End Set
End Property
Public Sub Add()
_age.Add(0)
End Sub
Public Sub Clear()
_age.Clear()
End Sub
End Class
End Class
How can I hide ,Sub Clear and Sub Add on class2, so they'll only be visible on class1, like;
Public Sub Clear()
names.Clear()
_class2.Clear() '<<<<<<<
End Sub
I want they do not be visible on Sub Main(), like they are below.
Sub Main()
Dim person As New Class1
person.AddAge("kid").Clear() '<<<<<<
person.AddAge("kid").Add() '<<<<<<
End Sub
If I put Protected, I class1 cannot access it. If I put Protected Friend, Sub Main() can still access them. Thanks for your help and time.
Used -Hans Passant- comment.
"Trust in .NET follows assembly boundaries. If you get two classes in one assembly then there are two programmers that know how to find each other if there's a problem. The only way to get what you want is to put these classes in a separate class library project. Which then lets you use Friend. And whomever writes that Main method doesn't have to be friendly."
Related
I want to call Dim objFkkiNinteiJokyoRpt As New A(objCsv) in class C. But class A Inherits Common. If now call contructor will An error occurred.Because type Object C.CsvGenerator diference type Object in common. I thnk now stop call to contructor common (or any other way) but i dont know how to do. Helf me please. Sorry because my english so bad
Public Class A Inherits Common
Public _objCsv As C.CsvGenerator
Friend Sub New(ByVal objCsv As C.CsvGenerator)
_objCsv = objCsvGenerator
End Sub
Public Sub New()
End Sub
End Sub
Public Sub New(ByVal objRSReportObj As Object)
MyBase.New(objRSReportObj)
InitializeReport()
End Sub
End Class
Public Class C
Private Function SelectCSV
Dim objCsv As New CsvGenerator("")
Dim objFkkiNinteiJokyoRpt As New A(objCsv)
End Function
Friend Class CsvGenerator
Inherits cmShare.cmObject
End Class
End Class
Public Class Common
Public Sub New()
MyBase.New()
End Sub
Public Sub New(ByVal objRSReport As Object)
MyBase.New(objRSReport)
End Sub
End Class
I'm trying to make a application, in this application I have a List(of T) collection that holds an object.
When processing the object I need to know it's Index from the list.
Example:
Public Class
Public oList as New List(of TestObject)
Private Sub Test()
Dim NewObject As New TestObject
oList.add(NewObject)
Index(NewObject)
End Sub
Private Sub Index(Byval TestObject As TestObject)
debug.print(Testobject.index)
End Sub
End Class
Is something like this possible? Ive seen it available in a reference file I used some time ago, but now I would like to make this available within my own class.
Can someone provide a sample?
PS: I know I can get the index using the List(Of T).IndexOf Method (T) but for future possibilities I would like to make the call from the object itself.
What usually happen is that they have a custom list, they don't directly used List(Of T) and store the list inside the object when they add that item to the list.
Module Module1
Sub Main()
Dim someList As New CustomList
someList.Add(New CustomItem())
someList.Add(New CustomItem())
someList.Add(New CustomItem())
Console.WriteLine(someList(1).Index)
Console.ReadLine()
End Sub
End Module
Class CustomItem
' Friend since we don't want anyone else to see/change it.
Friend IncludedInList As CustomList
Public ReadOnly Property Index
Get
If IncludedInList Is Nothing Then
Return -1
End If
Return IncludedInList.IndexOf(Me)
End Get
End Property
End Class
Class CustomList
Inherits System.Collections.ObjectModel.Collection(Of CustomItem)
Protected Overrides Sub InsertItem(index As Integer, item As CustomItem)
If item.IncludedInList IsNot Nothing Then
Throw New ArgumentException("Item already in a list")
End If
item.IncludedInList = Me
MyBase.InsertItem(index, item)
End Sub
Protected Overrides Sub RemoveItem(index As Integer)
Me(index).IncludedInList = Nothing
MyBase.RemoveItem(index)
End Sub
End Class
It looks like this
Public oList As New List(Of TestObject)
Private Sub Test()
Dim NewObject As New TestObject(oList.Count)
oList.add(NewObject)
End Sub
Public Class TestObject
Public index As Integer
Public Sub New(IndxOfObj As Integer)
Me.index = IndxOfObj
End Sub
End Class
If you necessarily need to have it as a property on the object I would suggest the following:
Public Class Main
Public oList As New List(Of TestObject)
Public Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Dim NewObject As New TestObject(Me)
oList.Add(NewObject)
Dim NewObject2 As New TestObject(Me)
oList.Add(NewObject2)
MsgBox(NewObject2.Index)
End Sub
Public Function Index(ByVal TestObject As TestObject) As Integer
Return oList.IndexOf(TestObject)
End Function
End Class
Public Class TestObject
Private _main As Main
Public ReadOnly Property Index() As Integer
Get
Return _main.Index(Me)
End Get
End Property
Public Sub New(RootClass As Main)
_main = RootClass
End Sub
End Class
If you happen to have the Main class as a Singleton you can skip the whole sending 'Me' into the constructor business. Then you can just call Main.Index without storing it as a property on all TestObjects.
I can't find an answer to my question so I'm asking a new one.
I have an object where I want to fill it's properties from another class in the same solution. But the object should expose read-only properties only so the outside-caller can't see nor access the setter (cause there is no setter).
What is the best way to fill the internal backing variables from the same solution? I know I could do it in the constructor but I want to be able to set the variables after creating the object.
Sorry for my weird explaination, maybe a bit of code could help.
This is what I'm doing now:
Public Class ReadonlyObject
Protected Friend Sub New()
End Sub
'Could use this, but don't want to...
Protected Friend Sub New(foo As String)
End Sub
Friend _foo As String
Public ReadOnly Property Foo As String
Get
Return _foo
End Get
End Property
End Class
Public Class FillReadonlyObject
Private Sub DoSomeHeavyWork()
Dim roObject As New ReadonlyObject
roObject._foo = "bar"
'Could use this, but don't want to...want to access properties directly.
Dim roObject2 As New ReadonlyObject("bar")
End Sub
End Class
With this, the ReadonlyObject's properties are correctly exposed as readonly but I'm afraid it's bad practice.
I've seen implementations like this:
Public Class ReadonlyObject
Protected Friend Sub New()
End Sub
Private _foo As String
Public Property Foo As String
Get
Return _foo
End Get
Friend Set(value As String)
_foo = value
End Set
End Property
End Class
Public Class FillReadonlyObject
Private Sub DoSomeHeavyWork()
Dim roObject As New ReadonlyObject
roObject.Foo = "bar"
End Sub
End Class
This works, but exposes the property with a setter. It's not accessible, but it's visible and I don't want that :)
So maybe it's only a cosmetic thing but I think it's nice to tell the caller (or at least intellisense) the property is strictly read-only.
Thanks, Jan
If you want to explicitly declare the property as read-only, but then still have a way to set it after it is constructed, then all you need to do is create your own setter method rather than using the one automatically created for you but the property. For instance:
Public Class ReadonlyObject
Protected Friend Sub New()
End Sub
Private _foo As String
Public ReadOnly Property Foo As String
Get
Return _foo
End Get
End Property
Friend Sub SetFoo(value As String)
_foo = value
End Sub
End Class
Public Class FillReadonlyObject
Private Sub DoSomeHeavyWork()
Dim roObject As New ReadonlyObject
roObject.SetFoo("bar")
End Sub
End Class
Or, you could create two properties, like this:
Public Class ReadonlyObject
Protected Friend Sub New()
End Sub
Public ReadOnly Property Foo As String
Get
Return HiddenFoo
End Get
End Property
Friend Property HiddenFoo As String
End Class
Public Class FillReadonlyObject
Private Sub DoSomeHeavyWork()
Dim roObject As New ReadonlyObject
roObject.HiddenFoo = "bar"
End Sub
End Class
Say I have a class with several methods within it. I want to organize the methods into groupings that can be accessed without constructing a new object each time. The purpose is to group the methods of the class into logical buckets
For instance:
Dim myclass as MyCustomClass
myclass.Shipping.Get_List()
myclass.Production.Get_List()
What is the best way to do this? I tried nested classes, but VB.NET won't let me access the methods as shown above.
so this is how i would do what you want
this is not the best design of the world but it would work
I would suggest you to move the actual get_list and other kind of method / property into the specific class while keeping the common one in the parent class, which in this case is test
but then, I have no idea what your code look like so from that point on, it's your choice
Module Module1
Sub Main()
Dim test As New test
test.Production.Get_List()
test.Shipping.Get_List()
End Sub
End Module
Public Class Shipping
Private parent As test
Public Sub New(ByRef parent As test)
Me.parent = parent
End Sub
Public Function Get_List() As List(Of Integer)
Return parent.GetShipping_List
End Function
End Class
Public Class Production
Private parent As test
Public Sub New(ByRef parent As test)
Me.parent = parent
End Sub
Public Function Get_List() As List(Of Integer)
Return parent.GetProduction_List
End Function
End Class
Public Class test
Public Property Production As Production
Public Property Shipping As Shipping
Public Function GetShipping_List() As List(Of Integer)
Return Nothing
End Function
Public Function GetProduction_List() As List(Of Integer)
Return Nothing
End Function
Public Sub New()
Production = New Production(Me)
Shipping = New Shipping(Me)
End Sub
End Class
With caution that you more than likely should re-evaluate your architecture, you could implement your pattern like this:
Public Class MyCustomClass
Private _shippingList As List(Of String)
Private _productionList As List(Of String)
Public Production As ProductionClass
Public Shipping As ShippingClass
Public Sub New()
Production = New ProductionClass(Me)
Shipping = New ShippingClass(Me)
End Sub
Public Class ShippingClass
Private _owner As MyCustomClass
Public Sub New(owner As MyCustomClass)
_owner = owner
End Sub
Public Function Get_List()
Return _owner._productionList
End Function
End Class
Public Class ProductionClass
Private _owner As MyCustomClass
Public Sub New(owner As MyCustomClass)
_owner = owner
End Sub
Public Function Get_List()
Return _owner._productionList
End Function
End Class
End Class
However, if your true intent is simply organizing the methods in a more accessible and logical manner, I would suggest considering:
Public Class MyCustomClass
Public Sub ShippingListGet()
End Sub
Public Sub ShippingListAddTo()
End Sub
Public Sub ShippingThatDO()
End Sub
Public Sub ShippingThisDo()
End Sub
Public Sub ProductionListGet()
End Sub
Public Sub ProductionListAddTo()
End Sub
Public Sub ProductionThisDo()
End Sub
Public Sub ProductionThatDo()
End Sub
End Class
Keep in mind, some people consider that difficult to read. I personally prefer organization along those lines so when the methods are sorted alphabetically they group logically.
I have found the solution I was looking for using interfaces
Public Interface ICompany
Function Company_List() As DataTable
End Interface
Public Class MainClass
Public Company As ICompany = New CompanyClass
Public Sub New()
MyBase.New()
End Sub
Private Class CompanyClass
Public Sub New()
MyBase.New()
End Sub
Public Function Company_List() As DataTable
My code....
End Function
End Class
End Class
I have these two classes class FootballAdmin makes use of the import Football from the projects references, what i need to do is in class MainForm is for the updateView method to access the list held by FootballAdmin and display it in the teamSheetListBox, i am unsure how access the list as indicated by ?????
Imports Football
Public Class FootballAdmin
Private fTeam As List(Of FootballTeams)
Public Sub New()
fTeam = New List(Of FootballTeams)
End Sub
Public ReadOnly Property Teams() As List(Of FootballTeams)
Get
Return fTeams
End Get
End Property
End Class
Public Class MainForm
Private fFootballAdmin As FootballAdmin
Public Sub New()
InitializeComponent()
fFootballAdmin = New FootballAdmin
updateView()
End Sub
Private sub updateView()
For each team As String In ????????
teamSheetListBox.Items.Add(team)
Next
End Sub
End Class
Help please!
The big hint I am going to give you is that team in your loop:
For each team As String In ????????
teamSheetListBox.Items.Add(team)
Next
Isn't going to be a String. It will be the same type: FootballTeam as in your FootballAdmin Class. Consider what you have access to in your MainForm that can get you to those types.