If we are within the derived class then ofcource we can use MyBase keyword to access base class's object reference . That's fine , how can we take that base class's object reference outside that derived class's definition.
My following code will explain what i want . Actually that is giving error right now, but it is explaining my requirement .[code]...
If we are within the derived class then ofcource we can use MyBase keyword to access base class's object reference . That's fine , how can we take that base class's object reference outside that derived class's definition.My following code will explain what i want . Actually that is giving error right now, but it is explaining my requirement .
Public Class Base
Public x As String
End Class
[code]....
Actually there is error in ReadOnly Property BaseReference's Getter . Error is "Error 1 'MyBase' must be followed by '.' and an identifier. " how can i get base class object reference in Main method ?
I 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?
I see a sample code that an object is instantiated within the class definition block. But when I test the folllowing, I got error "Process is terminated due to
[Code]...
Can 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 a Visual Studio 2008 solution with project A referencing project B as a project reference. Project B references System.Data.Linq, but project A does not. Everything compiles and runs fine. I like this arrangement because avoiding a reference to System.Data.Linq in project A ensures that it uses project B methods instead of directly accessign System.Data.Linq methods, which I want to avoid.
View 3 RepliesThe book "Beginning ASP .NET 4 in VB 2010" contains the following:NOTE: TaxableProduct inherits from Product.You can also cast in the reverse directionfor example, cast a Productreference to a TaxableProduct reference. The trick here is that this
View 2 RepliesHere is a test program I wrote to explore a facet of object casting ...
Module Module1
Sub Main()
Dim class1 As MyBaseClass = New MyBaseClass()
Dim class2 As MyInheritedClass = New MyInheritedClass()
Dim class3 As MyBaseClass = Nothing
[Code] .....
The problem comes with the TryCast statement on class3. My intention is that class3 remains as a baseclass, but when the TryCast is applied, class3 morphs itself into an Inherited class which is not what I wanted. So is there a gap in my OOP/VB.NET knowledge and this action is legitimate or should class3 still be regarded as a base class?
bare with me during this silly example. :-) Let's say I have a class like this:
Public Class Animal
Public iLegs as int32 ' Number of legs
Public bWings as Boolean ' Wings? Yes/No
End Class
And another class that inherits the "Animal" class and adds one more property:
Public Class ScaryAnimal
Inherits Animal
Public iScariness as int32 ' 0-100, how scary is it?
End Class
Now, if I have an instance of "Animal" with some values in it, and I decide I want to cast it to a ScaryAnimal for some reason, how do I do that without having to create a new instance of "ScaryAnimal" and copy each property value?Basically I'm looking for a way to do this, without having to write the lines marked with '*** below:
[Code]...
Here is the structure that I have:
Friend Class StandardFormatFile
Friend fileType As String
Friend numberOfSeries As Integer
[code].....
I have a class in which some of the fields are also classes.
I can put values in the "normal" properties, but in the others when o try to assign values it gives the: "Object reference not set to an instance of an object"
But the code compiles fine.
dados_Defenicao = New ServiceReference1.draftClaimEntryDefinition
dados_Defenicao.arCode = "123"
dados_Defenicao.claimMarket.warrantyType = "w" - Here it gives the error
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].....
I have an object (a third component gridview) which is serializable, and I need a deep clone of this object. I have the following code which throws the exception."The type System.Windows.Forms.Control in assembly System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKey Token=b77a5c5 61934e089 is not serializable".So the gridview's base class is System.Windows.Forms.Control, which is not serializable. How can I get a deep clone from the gridview? [code]
View 5 RepliesWhen I do this
Public Class cInherits : Inherits Panel
I get this: Base class 'System.Windows.Forms.Panel' specified for class 'MenuButton' cannot be different from the base class 'System.Windows.Forms.UserControl' of one of its other partial types.
How do I inherit?
String s = "test"; String is a class, so to use it we should create an object of it. But rather we just make a reference of it and give it a value. How is it possible and what concepts are used in it. The metadata of String class shows the following :
[Code]...
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 definition that I've seen other define properties that return collections of objects.
Public Property GetAllAdults() as Adults End Property I made the argument that this should be a method in the class, because it doesn't define an attribute of the class, and could not be extended with parameters. Is/Are there reasons why this should be defined as a property vs. a function?
How do I creat a simple array of class definitions?[code]...
View 13 RepliesI'm having trouble with the definition of an inherited generic class. I have two base classes that are defined like this:[code]
View 2 RepliesIn the following two code snippets, the code does the same thing, when I tested this.
Dim test As New Class1 Dim test As New Class1() Do the parantheses make a difference in some way? Is there an explanation of this in the msdn library?
I'm working a business layer (separate assembly) that will contain various business entities used in multiple client applications. One of the client applications is a WCF app that will need to serialize these entities. In order to properly serialize the entities, metadata for data contracts or for XML serialization must be added, but the serialization requirements may vary across applications.
Clearly I need the metadata separated from the class definition. So how do I add metadata to my entities for each separate application?
I call upon the VB ninjas out there. Here's my situation. I need to eventually be able to pass multiple models to a view. Currently I have a linq to sql class that, of course, has a bunch of generated model definitions. I need to make a model that implements multiple models. I somewhat understand how to do this in C#, but this project is testing my VB skillz. Here's some snippets from my linq to sql models. I need to combine these two into one model to pass to the view.
[Code]...
I have a base class which needs to define an enumeration:
BaseClass
- SomeEnum
I then need to create two derived classes from the base class and extend the values in the enumeration:
ChildClass1 : BaseClass
- SomeEnum
- SomeEnumValue1
[code]....
In C# or VB.NET can someone provide the syntax to do this?
In order to organize various methods of my MainForm class, I would like to categorize them into several files. Of course, the methods would still need to access form elements and additional variables I added in the MainForm class.
View 3 RepliesI am currently using reflection to retrieve all properties of a class. I return a collection of PropertyInfo objects and all is working fine.
My problem is, I want to check if a property has been defined in a base class implementation and is therefore inherited in the current class.
I have 3 classes that need themselves in order to do their work but if I declare them the old way it would end up being an endless loop.
As an ex C++ programmer, I know I could use include once but I don't know if there is any equivalency in vb.net Here is the picture.
I have 3 Classes : SQLConnector, ErrorHandler, LogHandler
- ErrorHandler needs SQLConnector to get some IDs from the Database.
- ErrorHandler needs the LogHandler class to prepare the Logs to be... logged.
- SQLConnector needs the ErrorHandler class in case there is errors happening.
- LogHandler needs SQLConnector to insert in the database.
- LogHandler needs ErrorHandler in case the insert is not successful (sends mail in that case)
As you can see, all three classes are needed. The reason why I can't use LogHandler and ErrorHandler as one class is that I will use that class to log transactions and changes according to some parameters. Log is in no way exclusive to ErrorHandler.how I can prevent to make an endless loop and use all three of them as I wish?
In a global module, I define a new type that can take 4 values:
enum tAction as integer
None
Update
Insert
Delete
end enum
A use this type in many places in my code to check the value stored in a variable (if MyAction = tAction.Delete then ...)
In a separate file, I define a class. One of the properties should return a value of this type:
public class XXX
private _Action as tAction
public property ClassAction() as tAction
[Code].....
This way I could check a class property in the same manner (if MyClass.ClassAction = tAction.Insert then ...)
However I get a syntax error in the property definition: 'ClassAction' cannot expose type 'Globals.tAction' outside the project through class 'XXX'
My entire program consists in a few modules, in a single project. How can I use my tAction definition in my classes?
I'm trying to return code like this (can be found here):
{"hotspots": [{
"id": "test_1",
"anchor": { "geolocation": { "lat": 52.3729, "lon": 4.93 } },
[code].....
I've been creating short test apps repeatedly to try to understand some of the concepts in VB.NET.For the most part it has been illuminating.I read Bucky's .NET knowlegebase tutorial on passing objects as parameters to newly created forms. He shows how to create a new class that inherits from the base form class and define a New() method with parameters Extending the concept I thought about doing the same thing with a form that was created at design-time (In this case Form2).
[Code]...
Base class has one field to hold numeric balance value. With 2 methods that accept arguments for adding and subtracting the new input calculating new balance. Sub class has four fields dates, transaction, memo and amount.I have a deposit form, and withdraw form. Each time one transaction is entered it creates an object with sub class fields, then adds to the account collection. My problem is not understanding how to call the deposit/withdraw method and pass the current transaction amount back to the base class to alculate the new balance. Does anyone have any links to information/tutorials on how to perform something like this? As you can see with my code I have tried various different approaches without any success.
[Code]...