Use Shared Property With Class Inheritance?
Jan 12, 2011I have a base class which defines a shared readonly property like this[code]...
View 5 RepliesI have a base class which defines a shared readonly property like this[code]...
View 5 RepliesI have:
Page.aspx
Page.aspx.vb
TestClass.vb
I'm trying to access a shared property of the TestClass class from the Page.aspx.This code works fine:
<head>
<script language="JavaScript">
<% if System.Globalization.CultureInfo.CurrentCulture.Name.ToLower = "pt-br" Then %>[code]......
I am trying to add shared members in derived classes and use that values in base classes...
I have base
class DBLayer
public shared function GetDetail(byval UIN as integer)
dim StrSql = string.format("select * from {0} where uin = {1}", tablename, uin)
end function
end class
[Code]..
currently there is error using the tablename variable of derived class in base class but i want to use it i dun know other techniques if other solutions are better then u can post it or u can say how can i make it work? confused...
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 Repliesi 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 Repliesworking 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 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 RepliesI seem to be drawing a blank. I'd like to create a "shared" variable that is shared with all instances of a class but not classes that inherit from it. For example.Class A: Shared list As New List(Of String): list.Add("A")
Class B Inherits A: list.Add("B")Class C Inherits B: list.Add("C")The end result I'd like is that any instance of A has just A in the list. Any instance of B has A and B in the list. Any instance of C has A, B, and C in the list. I can accomplish it by creating Instance variables, but I have to construct the list for each instance of a class. I'd like to construct it once for a specific point in the Hierarchy and then share it accross other instances of that class.
This is another one of my "I think it's not possible but I need confirmation" questions.I have a base class for a bunch of child classes. Right now, this base class has a few common properties the children use, like Name. The base is an abstract class (MustInherit)Technically, this means that everytime a child class is instantiated, it lugs around, in memory, its own copy of Name. The thing is, Name is going to be a fixed value for all instances of a given child. I.e., Child1.Name will return "child_object1", and Child2.Name will return "child_object2".
View 1 RepliesThe test is base on Visual Basic inheritance, need to create a derived class, and identify the inheritance.
View 5 RepliesCan 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 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
how variables declared with protected access in a base class are used to implement inheritance.
View 1 RepliesBackground: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]....
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]...
[using VB.NET, but I can easily read C# code in responses]I have a class called QuestionClipboard with ALL shared methods/properties. I previously had a QuesitonClipboard.doesClipboardHaveContent function that returned true/false if there was a Object on my 'clipboard'.I'd prefer to implement a Dependency Property so I can allow this true/false value to participate in data binding.The "GetValue(dp as DependencyProperty)" method requires an object instance, which would mean that my Property CAN'T be shared!Here is what the code would look like in my perfect world... Of course, the word "Shared" before the property declaration renders this code useless.
Private Shared clipboardHasContentPropertyKey As DependencyPropertyKey = DependencyProperty.RegisterReadOnly("clipboardHasContent", GetType(Boolean), GetType(QuestionClipboard), _
[code]....
i have an multi-threading applicaton. so I am using system.threading.thread class to create thread. each threads call its own class and inside each class i am accessing webservices. I need to have status returned from each webservice. thats why I defined a shared property as list of generic object which will be updated within each class called its thread. but I have an hesitation that when I run application on the server. this shared object will be used by all instances of web application. Is it true or shared properties is used only for its own instance?
View 5 RepliesSuppose I have a class of objects called Porky with a property called IsHuge:
Public Class Porky
Public Property IsHuge As Boolean
End Class
Now I want to make a special kind of Porky -- let's call it UberPorky -- for which I want to change ALL instances to either IsHuge or not IsHuge. What I'd like to do is this:
Public Class UberPorky
Inherits Porky
Public Overrides Shared Property IsHuge As Boolean
[code]....
The trouble is, I can't do that. I'm not allowed to reference MyBase or Me in a Shared property.
I have extended an Entity Framework 4 entity class with a calculated property in a partial class. This member is not available on the client to which the entities are exposed via WCF RIA Services.when using C# appears to be changing the extension of the partial class file from .cs to .shared.cs. I tried this with my VB.Net solution (.vb to .shared.vb) and got a long list of errors. I believe what happened is that the partial class lost its association with the entity on the client - it inherited from object rather than EntityObject.
My best guess is that this is related to the way that VB.Net handles namespaces.Each project has a 'Root Namespace' which is prepended to anything that is defined within a code file. C# has a 'Default Namespace'which is the namespace into which new types are placed by default - via a namespace statement within the file.The partial class is probably having the client namespace prepended to it which puts it into a different namespace than the entity with which it is associated on the server.Is there any means of extending an entity in such a way that those extensions are available on the client via WCF RIA Services and VB.Net?
I have a very simple class that holds a few public properties - ID, Text, Colour, etc. and a Boolean called 'SelectedItem'. Just like the Checked property on RadioButtons, only one item can have its SelectedItem property set to True within a particular group. Note: there will be several separate groups (lists), each allowed to have only one item with SelectedItem = True.
My first thought was that I would probably just have to handle everything outside of the class, setting SelectedItem to False for every other item in a particular list when another item was selected. But that seems rather inelegant to me. So I've been trying to think of how this might be done within the class. For example: could I perhaps have a private string property called say "GroupName" - set in the New sub when adding a new instance of the class - and then use a private shared method to set every item's SelectedItem property to False, provided the item has the same GroupName as the newly selected item? I would have a go at doing this but I have no idea how to enumerate every instance of a class from within that class, or whether that's even possible. Is it? Or is there another (better) way to achieve my goal? Here is a cut-down version of what I've got so far:
Public Class ResourceItem
Public ID As Integer
Public Text As String[code]....
As can be seen: instead of instantiating a new ResourceItem and passing that as an argument to the manager's Add procedure, I'm simply passing the details of the new item and the procedure is creating the item from those. I don't know whether this is a good or bad idea - please advise - but I've done it because I couldn't figure out how to make the SelectedItem property only writeable by the manager, so I wanted to avoid having directly accessible objects that could have their SelectedItem property set to True without it deselecting all the other items in the same group. Of course that still leaves the possibility of setting a variable to one of the manager's list items and setting it from there, so I would still like to know how I could prevent that, if possible.
UPDATE: I didn't use the code above in the end, deciding instead to go with Cyborgx37's solution - which seems to work perfectly well for me despite the warnings about best practice. I also realised I would need to use the same class in another scenario where multiple items could be selected, so it was easy to add a Boolean property to the manager to enable that.
I have the following code:
Public Class MyColorsClass
'Constructors
Public Sub New()
'Empty Constructor
[code]....
However, if the empty constructor was called to instatiate this class then the colortype is not yet set. Therefore, if one accesses the 'IsColorCool' property it will always return 'False'. Now for the sake of this example, I must keep the empty constructor as part of the class.Now I could add some code in the 'IsPropertyCool' to check and see if a ColorType has been defined, and throw an exception if it has not been set, but I don't really want to do that.I also could always move the logic OUT of the property and into a method on the class called 'DefineIfColorIsCool' or something, and make the owness on the caller to make sure the method was called if they want to use the property 'IsColorCool'?
I am making a small application in which i have added a class module and a window forms in vb.net. i want to acess the shared variables and mathods of class without making any object.
View 8 RepliesI was looking on the interweb to see if there were any good examples on how to initialize shared members within a class while still initializing instance variables.[code]How do I initialize both instance and shared members without re-initializing the shared members every time an object is created from a class?
View 1 RepliesI've got a shared class (static in C#) which mostly carries some settings data that any class in the application can read and sometimes write. Also there are some static properties which holds some internal states.
Now I want to revert this class to initial stage of it. With all default variables etc. Assume that the user want to reset the current state and start over without restarting the application.
In a singleton model I'd simply renew it with something like this :
Public Sub Reset()
_Instance = New MyClass()
End Sub
However this is not possible in a Shared class. Or should I switch back to Singleton?
I have no idea what is going on here but it is strange to say the least.I created a new solution in VS2008Pro under windows 7 This solution has 2 projects one for the pc and one for a CE based device.There is one class module which is shared between the 2 projects.In VS2005 under xp this same basic project worked fine but here I am seeing error messages that appear out of no where.
Example the CE portion flags 3 lines initially 1 related to a file i.o function and 2 others related to socket methods. All three of these were supported in VS2005 using framework 2.0 which is the same framework I am using here. This is just the tip of the ice berg however.If I attempt to run the code it runs fine for the pc client and of course not for the CE device. If I make any kind of change, add a line, comment a line or just add a comment I get lots more errors with odd messages that are not even valid.
In one case after I saved it jumped from 3 errors to 30, in another case to 50 and yet another to 144 errors yet the only errors that were present were the original 3 that were flagged.The ide threw errors like Try Catch must end with matching End Try.Get no longer supported ' apparently referring to the binary file get but here it is used as the get portion of the property.Get must end with matching end get.It also started complaining about functions and data types.For example saying "an is not declared" pointing to the word Boolean Or telling me my functions are not declared point to only 1/2 of the function name.
I do not see any errors in the code and it reports no errors in VS2005 under XP.As a test I tryed adding a new property to the project after it was telling me there were 144 errors. I allowed the ide to do most of the work and when I hit enter the errors went back to 3. Then I saved the project and the errors went to 105 pointing first at the new property just created.
I have a function that 2 derived classes use, but the third doesn't, would it make sense to just leave it in the base class, even though one of the 3 derived classes doesn't use it?The only way I could think of disallowing the third class is to basically create an intermediate class that is derived of the base, then the 2 that use the common function are derived off the second class.
Is it possible to prevent the 3rd class from using the function, while letting the two that are supposed to use it, use it?Does that just seem to go overboard, I mean as long as I don't "try" to call the function from the 3rd class, it shouldn't be a problem, I just was interested if there was a way to prevent it all together without a lot of hassle.
I have large group of functions that I would like to store in basically a library and simply call the functions from the controls on my forms. Back in VB 6 I would have done this with a module, but now I have been told that a Public Class is the correct way in .NET. How should I go about doing this?
View 2 RepliesI have a class in a shared library, that I have added references to on both the webservice and the client project. One of the functions in the webservice returns a list of this class.
when I try to cast the return value into a List of the class on the client side, I keep getting an error telling me that a 1-dimensional array of type '<webservice.class>' cannot be converted to type '<sharedlib.clas>'.
The reason that I put the class into the shared library, was because I wanted the webservice to return strongly typed data, but I also have a couple of methods in the class. I dont care about them on the server side, but they are needed on the client side. I figured that this would be the "better" method, since in a shared library it is only declared once for both projects.
I have created a Interface and a couple classes that implement this Interface. I am in the process of developing a Shared Class that utilizes the functions that each of the individual classes have, due to the interface implementation.What i need to know is how do i develop this Shared Class so that way each of the methods within it are restricted to a single data type. This single data type needs to be restricted to any class that has implemented the Interface.
Some examples:
Public Interface IVector(Of T)
Sub Add(ByVal v2 as T)
[code]....
As you can see it would allow me to develop one form, since i have standardized the required Subs/Functions for any class the implements the IVector interface. As i am still in developement, i was wondering if my current understanding of the method generics is correct in its current form or what i would have to do to make the Generic Shared Class work in the fashion that i am looking for in the example implementation.
I am having trouble trying to get my shared class final value
Class name : Encryption
Public Shared Sub PassEn(ByVal PassTxt As String)
Dim strText As String = PassTxt
Dim salt As String = "61651616516161651615"
Dim bytHashedData As Byte()
[Code] .....
I am trying to call this from the call and get the return hash but when I try to make a global variable it doesn't allow it. How would I call this and get "HashValue" on to a textbox on my form.