Using Properties With A Mustinherit Class In VB2010?
Aug 4, 2010
I am struggling to get inheritance to work in the way that I understand it is supposed to work.I want to create a base class that uses MustInherit. It will have properties. The derived class should have access to those properties. But how do I get and set property values for an instance of the derived class?
So I have Public MustInherit Class Baseperson
Private _Name Public Property Name as string
[Code]...
But this does not provide encapsulation of the property so it would not seem to be a good solution.
I see various documentation on MSDN that talks about "abstract" classes having properties but I don't see how to make it work.
i have 2 mustinherit classes where one is a generic one:
'Visual Basic 2008 - .net 3.5 - Any CPU Public MustInherit Class BaseObject
End Class
Public MustInherit Class BaseObjectList(Of T As {New, BaseObject}) Inherits List(Of T) End Class[code]...........
i receive: "Type argument BaseObject is declared 'MustInherit' and does not satisfy the 'New' constraint for the type parameter"users would never enter data in the wrong form,files they choose to open would always exist and code would never have bugs.
I've got an Interface that dictates classes that implement it to use a large amount of properties and a few methods. I've been using this interface for some time and I have a large amount of classes that implement it.
Now, I need the interface to become a MustInherit (abstract) class, because I need to implement a single method that must be the same for every class implementing the interface (I mean the implementation must be the same, hence I cannot use an interface anymore).
Is there a way to do this automatically, perhaps even using third party tools such as resharper (which is C# only I think?) or similar? I get a headache even thinking about the work I need to do to make this change manually[code]....
What is the difference between a class with protected constructors and a class marked as MustInherit? (I'm programming in VB.Net but it probably equally applies to c#). The reason I ask is because I have an abstract class that I want to convert the constructors to shared/static methods. (To add some constraints). I can't do this because it's not possible to create an instance in the shared function.
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".
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 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
Once time, me needed to compile the library with different code inside class which determined with prroject wich inherits this library At first I tried in project declare #const and in library to use condition with #const,
I wrote a function that copies the properties of one class to another so make a copy of an object.So something like
MyObject myObject = myOtherObject.MyCustomCopy(myObject) where myObject and myOtherObject are of the same type. I do it by bascually doing myObject.prop1 = myOtherObject.prop1
[code]....
I am pretty sure in the past I used a .NET object that automaticaly did this, by reflection I guess, but can't remember it ... or an I imagining that such a method exists?
I'm looking at a VB.NET class (that I didn't write) that is declared "MustInherit" (abstract in C#, I believe) that has three methods, all of which are defined as "shared" (static in C#). There are no properties or fields in the class - only the three methods. From an OO perspective, does this make any sense?
My thinking is no, because by making it MustInherit, you're essentially saying you can't create an instance of this class - you must inherit from it and create an instance of the derived class. But since all the methods are shared, you'll never actually create an instance of the parent class anyway, so the "MustInherit" does no good. You might as well not mark it MustInherit and just inherit from it whenever you want.
When attempting to create a UserControl type that must be inherited, when I try to edit one of its child classes in the Form Designer, I am not allowed to edit the child UserControl with the message:
To prevent possible data loss before loading the designer, the following errors must be resolved: 1 Error
The designer must create an instance of type "XX_ExpandContentsPanel2.IOCardMaster", but it cannot because the type is declared as abstract.
This error goes away if I remove the "MustInherit" restriction.Is there some way around this or do I just have to accept the (bonkers-mad) restriction, and not declare my class as as MustInherit, even though it's not a useful control in its own right?
as you might guess from the variable names I'm making a game (but this problem isn't game related!) which involves multiple "bullets" moving along straight trajectories. This is my attempt at changing my code for firing one bullet into one for firing many bullets at once. It works perfectly except for one thing.The class I made (BulletClass) to contain all the things needed to move the bullet isn't setting all of its properties correctly. I apologise for the walls of code however I wasn't entirely sure whether I should chop bits out. I wanted to colour code my code so that you could scroll through and see the subs where things have gone wrong, but apparently I can't even code a new thread. Let alone a video game. Instead I'll just list them, you can search for them if you like or just scroll through at your leisure.
[Code]...
In a nutshell: the properties TargetPosY, TargetPosX, ShipPosX and ShipPoseY are not working properly. As a result the calculations involving them are skewed and the bullets always travel directly downward.
I've got a Dictionary collection of a certain class with dozens of string properties.i'd like to create a datatable from this info and map these properties into Datatable columns, and for each member of the dictionary maps it to a row...
i could type out column names based on the class properties, but thats a bit specific and hard coded.
What I want to do is something like
Dim mytable as datatable For each string_property as property of myclass Dim column as new datacolumn(string_property.name) 'column add to table etc Next I'm unfamiliar with how to do this, maybe the Reflection classes are useful - perhaps the guru's can point out an efficient solution?
Is there a way to clear all the properties in a class, because i have a class where all my properties were stored, can i clear all those in just a short code?
I've tried searching... a lot for the answer, but as I'm not too sure what exactly I'm trying to do I can't seem to find anything. I'm trying to write a dll in order to handle errors thrown from a vb.net app. In the dll I need several forms (I'm not totally sure if they can have forms - I'm a bit of a newbie when it comes to dll's) for which the user can type in their message about the error and submit it.
I have dynamic class with varied numbers of property. At one time I need to save all data from this class. So, to do the For/Next or Do/Loop, I need to know, how many properties in class for now? Is it possible to findout the property numbers and after - property names list?
For example. I have a class INI, were was .Path as preexisted property. Then the few properties has been added and INI start consist of .Path, .Size, .Color and something else.
I dont want to keep in mind all properties has been added. All I want to get some simple loop to read all properties names and values to dump it to the file. Some sort of this[code]...
I am filling a form with values from a class, which is working fine. But now I want to take the changed values in the text box and modify the class. For some reason I have not been able to get the syntax.
I have created a class named CustomerType - CustomerTyp, which includes 4 properties - ID, Name, Number, Selected. I need to make a code, which determines how many properties has the class.
How can I get all the properties of a class that implement a specific base class or interface? I have a properties class that contains several other property classes. Some, not all, of these classes implement an interface. I would like to know if it's possible to iterate over all properties of parent class for child-classes that implement the target interface. It sounds like a job for reflection? I'm just not sure how. Can it be done via the "PropertyInfo" object?
I have an app with my own class "something".So, Im going to one of the my modules and declare public var as a class. After fillup this class by date, I would to get this date from the other module of my app. But there this var is unavailavle (its mean I have to redeclare it again. Its mean I'll lost
Whats the best way to iteract through a class to get all the properties names? So far i have this code
Dim classInstance As New ServiceReference1.draftClaimEntryDefinition For Each PropertyItem As PropertyInfo In classInstance.GetType().GetProperties() Dim strPropName As String = String.Empty[code]....
My problem is: I will receive a xml file, and have to get the data in a class, but as mentioned before the class has a lot of classes as properties, and i want do do it without hardcode, I want to loop the class properties names and compare them to the xml tags (it haves the same name as the class properties), and put the values from the xml file in an instance object of the class.
Code: Public Class Customer Public Property AccountNumber() As String Public Property AccountCreationDate() As String
[code].....
This works but I tried to loop thru the properties of the class with a For Each/Next loop. It does not work as the intellisense won't co-operate with Items I think i need like "PropertyInfo" . After reading, I see that only thru Reflection can I do this. Well, Reflection has me baffled at the moment.
I have a property grid and I want to be able to set the selectedobject to a class. The class contains properties. This is what I have, but it 'OtherFiles' is not an object.
pgProperties.SelectedObject(OtherFiles)
How do you create a class as an object. In VB.NET 2008 please. C# is ok.
I want to have use several versions of the same property within a userControl that inherits a textbox. How can do this if it is possible?I tryed using an object data type insted of the integer and double but it seems like object datatypes carnt be used within a class, because when I tried to use the control the VALUE property was disabled.
'PUBLIC PROPERTIES Public Property Value() As Integer Get[code].....
I 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?
I have a listview but I would like to add 3 properties (for example one of them is "image") to the listviewitems in it. I was fine with making a custom class with the 3 properties and just inheriting ListViewItem but now I need to use MultiSelect, so it means doing things like(in For Each loops):
ListView1.SelectedItems.Item(i).Image don't work because it returns a ListViewItem not my CustomClass. I could always do : Ctype(ListView1.selectedItems(i), MyCustomClass).Image
But using that over and over again seems like a waste/wrong way to do it?
Is it possible for one class to access an array of values within another class as a readonly property of the second class? All of the examples and references on class properties imply that one can only retrieve one value by calling a class' property.
