Derived Classes Cannot Raise Base Classes
Jul 10, 2009I m trying to raise Click event of Textbox explictly but I m getting "Derived classes cannot raise base classes" error.[code]....
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[2008] Base Class Inherited By 2 Derived Classes
Jan 30, 2009i've finally got round to learning about classes and inheritance, but i'm not sure how to proceed. i have a base class Employee, which is inherited by 2 derived classes. how do i use the same Employee class in both derived classes? obviously if i write a sub new for both of them + declare a new Employee class, they won't be using the same class. heres my Employee class:
[Code]....
Design Patterns - Inheritance - Do All Properties In The Derived Classes Have To Be Declared In The Base Class
Aug 8, 2011Background: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]....
VS 2010 : UserControl MouseEnter/Leave Events Aren't Firing - Cannot Raise Base Event From Derived Class
Feb 18, 2011When i use my UserControl in a project my Mouse Enter & Leave events aren't firing, i assume i fix this with a raiseevents in my usercontrol. However when i try to do this it says something about "cannot raise base event from derived class".
View 7 RepliesDeclaring Enums Across Derived Classes
Sep 21, 2009I am developing a program in VB.NET. I have an enum called PriceType that is declared in a super class ItemPriceBase. There are 3 classes that derive from ItemPriceBase - ItemPriceMeasured, ItemPriceNDI and ItemPriceExtraCost. The subset of PriceTypes for these classes are totally unique from each - Measured prices are 1 to 6, NDI prices are 7 to 15 and ExtraCost prices are 16 to 22.
Is there a way declare the enum in the super class and then extend the enum in each of the derived classes so that they only have access to those options, yet I can still access a property in the super class that returns an enum of PriceType?
Invalid ServicedComponent-derived Classes Were Found In The Assembly?
Aug 4, 2009I have created a strong name key file and run the gacutil to attach the dll to the assembly.. When i try to run the regsvcs bankaccounts.dll i get the following error...
Invalid ServicedComponent-derived classes were
found in the assembly.
(Classes must be public, concrete, have a public[code].....
Raise An Event Across Classes And Module?
Nov 20, 2009I have a WinForms class that presents a TreeView of some network nodes. I have a separate module that interfaces with the network and detects when nodes are added or removed. I would like the module to trigger the TreeView when the network changes.Example
Public Class Main
Friend Sub TV_Main_Network_Click ( ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
[code].....
.net - Events In Base Classes?
May 19, 2009i have a base class which declares the event StatusTextChanged. My child class, of course cannot directly raise this event.
[Code]...
C# - Using Many Classes In GUI That Inherit From A Base?
Oct 20, 2010I have classes setup similar to this:
<DataContract()> _
Public MustInherit Class SystemTaskProcessBase
Public MustOverride ReadOnly Property Name() As String
Public MustOverride ReadOnly Property Description() As String
Public MustOverride Property Result() As SystemTaskResult
[Code]...
I need to use these classes on the client system, but also need to be able to create these "tasks" through a management interface. Each class (Task) that inherits the base, could have its own properties that are unique to each class, but at the same time, share the same common base class properties. For example, the above shows a reboot task and a delete file task, the delete file task needs to know which file to delete, so has a property for that. But the reboot task does not need this property. So when the management application is creating these tasks, it shouldn't provide a text box for the file property for the reboot task. There may be more tasks created at a later date with completely different properties.
How would I go about providing the WinForms management application a way to enumerate each class into a ListView for example, and allowing the user to create these tasks and filling in the dynamic properties that each class would have? Desired functionality would be to create a task form that creates dynamic controls available for the properties as needed, depending on the public properties in each class, but at the same time have the base class properties available as well.
Base Classes On Proxy Objects
Sep 25, 2011I 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]....
Make Base Interface For Generic Classes?
May 25, 2010I'm trying to create a base interface for a class of mine that uses generics. However, I cannot figure out how to declare a property of the interface when its type won't be defined until the class is initialized.
To clarify, consider List(of T), which according to msdn, implements IList (among other things). Note that IList is not the same as its generic counterpart IList(Of T). So that mean any List(of T) can be converted to IList, which simply returns an object for its items. That's what I want to do with MyClass(of T), be able to cast it as IMyClass regardless of what T is.
But when I try such as:
Interface IMyClass
Prop A as Object
Class MyClass(of T) Implements IMyClass
Prop A as T Implements IMyClass.A
I get a signature error for the last line, even though object is broader than T. What am I doing wrong, or how exactly did Microsoft manage to make List(of T) implement IList?
VS 2008 Casting Subclasses, Base Classes?
Jun 26, 2010I am a VB6 programmer learning VB.Net and am having trouble with the following concept.
[Code]...
Specifying Different Page Base Classes For Different Directories In Web.config File?
Mar 17, 2010I have a website (coded in vb.net) with an "admin" section (the admin section being a folder in the actual site)... So in every page of the site I'm using my own custom class as the page base (which has been set in the web.config file) but I want to inherit from different class for the files in the "admin" folder... Is there any way to inherit different classes for pages in different folders using the web.config or some other equally as global method? (meaning some other way than inheriting on a per page basis.)
View 1 RepliesUse LINQ To Filter Collection Of Nested Classes To Yield Dictionary Of Unique Properties Of Those Classes?
Jan 23, 2012I have two classes, one nested in the other. [code]Neither "Name" or "ID" are unique between operations and records.I wish to construct a dictionary using LINQ = Dictionary(Of String, Of List(Of Integer), whereby the keys are uniqe examples of Names in my collection and the values are the collective set of distinct IDs that are associated with those names.
View 2 RepliesVS 2005 - How To Make Custom Base Classes Available To Future Programs
Oct 22, 2010I have written multiple programs in the past that deal with cad data. Points, lines, arcs, etc. For each program I ended up creating slightly different versions of some really base classes like a class that defines a point:
<Serializable()> Public Class Point
Public x As Double = 0
Public y As Double = 0
Public z As Double = 0
End Class
My question is how would I use that class in such a way that it could be in a namespace and imported into any future project that I write?
VS 2010 Structure Classes So That The User Interfaces Though A Single Class While The Supporting Classes Are Hidden From Their View?
Jun 13, 2012How can I structure my classes so that the user interfaces though a single class while the supporting classes are hidden from their view? I think its best understood in an example:
Public Class MyInterface
Public Economic as EconomicClass
Public Sub New()
MyBase.New()
[code].....
So you might ask why am I even separating them? It's strictly for others who will be working with this interface. I need to funnel them though a logical structure:
interface.Economic.MyMethod
interface.Currency.MyMethod
etc
This way everything is already handled for them in the background and they only need to run the method they need. I don't know if I can have it both ways in VB.NET.
VS 2010 Calling Subs And Functions Within Classes That Are Within Classes?
Oct 24, 2009Here is some example code of what I mean:
vb
Public Class Form1
Private Sub Button1_Click(ByVal sender as Object, e as systemEventArgs) Handles Button1.Click
[Code]....
Loop And Enumerate Properties Of Nested Classes In Nested Classes?
Sep 24, 2010so far i got
code
For Each item As Reflection.FieldInfo In GetType(NameSpace.ClassWithNestedClasses).GetFields
rtfAppend(item.Name & ":" & Tab & item.GetValue(Me))
Next
For Each item As Reflection.PropertyInfo In GetType(NameSpace.ClassWithNestedClasses).GetProperties()
[code]...
which gets me the simple string vars and properties of my top class, but how can i apply this to loop through all sub classes and get there vars and props?
VB XML Classes Vs String Classes?
Oct 13, 2011Searching the internet finds no less than 700 different ways and opinions to accomplish what I'm trying to do, and I would just like to know the simplest, most bullet-proof way possible.
[Code]...
I simply want to extract the string "bar," which is inside <hostName></hostName>I can do this easily enough with simple string functions, but I'd like to do it with one of the .NET XML classes/methods.
V B 2008 Express Book - Can't Connect To The "Service-Based Data Base" Or To The "Linq To Sql Classes"
Jan 6, 2010I can't connect to the "Service-Based Data Base" or to the "Linq To Sql classes". I tried all that I've read in the Forums for days : ( I removed the VB 2008 and SQL 2205-2208, then upload VB 2008 from my CD only. I'm starting a Web Technology class in 2 weeks, and the complition of the book is my entry requirement.
View 4 RepliesVS 2008 Base/Derived Class?
Jan 17, 2010Trying to implement some sort of commit/rollback functionality in my base objects. I have it working with some help from google. However, I have a question My Base Class has a BeginEdit as shown below -
[Code]...
Now, what I'm confused about is if I create another class, Class1, that inherits the base class. I add some properties such as Name, Age, Location, etc. to Class1.When I do Class1.BeginEdit, wouldn't "Me.memberwiseclone" make a copy of Class1, then CType try to cast it from Class1 to the BaseObject class? How does that work if Class1 has additional properties like the Name, Age..blah blah? Where do those gets stored in the Base class? I'm having a hard time wrapping my head around the concept...
Best Pratice In Inheritance - Three Classes Employee, Manager And Salesman. Manager And Salesman Classes Inherits Employee Class
Jul 27, 2010I have three classes Employee, Manager and Salesman. Manager and Salesman classes inherits Employee class.
Employee :
Public MustInherit Class Employee
' Field data.
Protected empName As String
Protected empID As Integer
Protected currPay As Single
[CODE]...
Manager :
Public Class Manager
Inherits Employee
[CODE]...
Salesman :
Public Class Salesman
Inherits Employee
[CODE]...
Now I have created a object of salesman and manager using the following code:
Dim objSalesMan as Employee=new Salesman("xyz",1,2000,5000)
Dim objManager as Employee=new Manager("abx",2,5000,"production")
Is this a good programming pratice or should I use:
Dim objSalesMan as new Salesman("xyz",1,2000,5000)
Dim objManager as new Manager("abx",2,5000,"production")
Hide A Derived Method Of Base Class?
Sep 10, 2009I would like to inherit from the Data.DataColumn in order to produce a DataTextColumn. That means that in the derived class, I dont want to see the non-applicable AutoIncrement property and the like - all I want to see are properties that apply to string types.[code]...
View 5 RepliesVS 2008 Same Interface, Base And Derived Class?
May 11, 2012I'm struggling here.. I know I can disable the warning manually. However I'm not sure if this would be the right way to go about this.
Here's my interface..vbnet Public Interface IPopulatingClassBase Property Identity() As Int64 ReadOnly Property Dirty() As Boolean Sub Populate_Class(ByVal RecordID As Int64) Sub Save_Class() Sub Reset_Class()End Interface
[Code]...
PS In my example think of it as classes that populate with data from a database. The parent class would be an organization, and the derived class a location. Both populate and have similar functionality. The only difference is locations are an entity of an organization(the data record for a location constraints it to an organization) upon loading location data I also populate the organization class. This is a real example of what my project does.. so having said I just want to know how I can get around this warning, and if not would it have any consequences if I left it as-is.
Using Reflection To Attach / Detach Handler Of Base Event In Derived Class
Dec 13, 2009I am just curious, if there is some way to attach handler to my derived classes base event, if I know EventInfo and I have Delegate to handler function. I have tried MyEvent.AddHandler(CType(Me, BaseClassType), MyDelegate) already, but no positive result at all. Consider being in need of attaching handler to custom event at runtime, while derived class possibly shadows this event.
View 2 Replies.net - Can A Generic Version Of A Derived Class Override A Base Method Using The Generic Type
Apr 13, 2012Consider:
Public MustInherit Class Column
Public ReadOnly Property ReturnSomethingUseful() As Object
Get
'return something useful
[code]....
But this gives the following error:
Public Overrides Function ParseValue(sValue As String) As Boolean'
cannot override 'Public Overridable Function ParseValue(sValue As String) As Object'
because they differ by their return types.
I accept that you can't do this, but I'd like to be able to preserve the semantics of what I'm. trying to do, which is to have an untyped version that deals with Object, but a typed version in derived classes that knows about the specific type T.
.net - Suppress A Property Or Method From A Base-class In A Derived Class?
Apr 7, 2011Supose a base class
Public Class airplane
Private var_num_seats As Integer
Private var_num_engines As Integer
[code]....
Obviously, I don't wish that the class Glider has the method "start_engines" neither the property "num_engines". Otherwise, other child classes may have. How can I supress these property and method in child class, not just ignoring (if I can)?
Access The Base Class Inside A Derived Class?
Oct 22, 2010How do I access the base class inside a derived class?
View 1 RepliesCasting From Base Type To Derived Type
Jun 29, 2010I'm wrestling with this treeview control. I have extended the TreeNode class to attach some extra data to the node. Basically, I added one property:[code]Is there a way to cast from a base type to a derived type?
View 11 RepliesFlattening An Object Hierarchy Using A Shim Class - Initializing Derived Object Properties From The Base Object?
Jul 10, 2010I am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:
newProperty1 - a new string property of the derived class
flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class
Code example:
Public Class derivedObj
Inherits baseObj
Private _newProperty1 As String[code].......
Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.
Code example:
' property names are in the string array fieldNames
'baseObjQuery is an ienumerable of baseObj
'derivedObjList is a list of derivedObj[code].....
Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?