I am really trying to follow the DRY principle. I have a sub that looks like this?
Private Sub DoSupplyModel
OutputLine("ITEM SUMMARIES")
Dim ItemSumms As New SupplyModel.ItemSummaries(_currentSupplyModel, _excelRows)
ItemSumms.FillRows()
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Consider a MyForm class that contains a shadowed implementation of Show(). It also contains a CreateForm() method, which accepts an instance of the form and calls the shadowed sub:
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Consider:
Public MustInherit Class Column
Public ReadOnly Property ReturnSomethingUseful() As Object
Get
'return something useful
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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.
I have been using a pretty slick generic invoke method for UI updating from background threads. I forget where I copied it from (converted it to VB.NET from C#), but here it is: Public Sub InvokeControl(Of T As Control)(ByVal Control As t, ByVal Action As Action(Of t))
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I can do this without problem.
Class A
End Class
Class B : Inherit A
End Class
Dim Obj1 As A = New B
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).
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I have an interface that i have declared some of the basic internal functions, subs, properties, etc. This interface is then implemented into 3 pre-defined classes. These classes are end-use classes so they dont get derived or inherited elsewhere. I am trying to create a generic shared class that can operate on each of these 3 predefined classes and potentially more as long as they implement the interface.
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Public Class notifierMain
Public Class Contacts
Inherits List(Of row)
Public Sub New()
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When I debug this winforms application I get curType = "notifier.notifierMain+Contacts+row" I want to the Validate function to know it is in MyContacts. How do I do this?
Write an overload for every numeric type or if possible constrain a generic extension method to just numeric types.
View 2 RepliesI have a Journal that records entries for different types: Journal(Of ParentT)
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I am trying to construct a generic interface class with generic functions. My goal was to use this to implement multiple worker classes for database interaction that have the same basic functionality. Each class will deal with different object for example, category, product or supplier but unless the the functions in the interface are generic that this won't work.This is the interface code that I have but I don't know if I have done it correctly. [code]
View 2 RepliesI want to create some reusable code in my forms.The idea is that a class is growing when more subroutines are added so, I need to store the finished subs somewhere to make place for others, this way I don't lose myself searching through the entire class
View 4 RepliesInterface makes sure a class does have a Method / Property, However is there a way to create an unInterface, making sure that the class does not have a method / property or is there a way to implement something that will unimplement every other implements except for itself?
what i want to do: i've got a class that serves as a storage for information only, so i decided to give it a blank interface IBank, the other classes that share this feature will implement this interface. they should not implement any other interface the use is that when i seek out the interface of a class and realise that its IBank i know that its just a class for info storage.
I am learning vb.net and I am having trouble wrapping my head around the following... I can create several properties of a custom class and get/set values or I can create a method to set them all at once. If each property is going to allow read and write should I just make a method to assign values all at once? I assume that I am missing a very important piece here. Example: I can create 2 properties:
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I am working on a general helper class to sort ListView SubItems. I wrote a base class that has much of the code I need. It includes a MustOverride for the Compare method so that the various inherited classes can implment their own comparisons based upon their type. For the value types, I end up with very similar code such as the following, where x and y are ListViewItems: Public Overloads Overrides Function Compare(ByVal x As Object, ByVal y As Object, ByVal sortColumnIndex As Integer, ByVal sortOrder As System.Windows.Forms.SortOrder) As Integer [code]
View 3 RepliesI have a class myClass. MyClass has a property myName. I have a generic list myList(of myClass). I have to check if value of myName in all myClass objects in myList is same and is equal to a string myString. I have created a method:
Private Function IsMatching(ByVal objMyClass As MyClass, ByVal strMyString As String) As Boolean
If objMyClass.MyName = strMyString Then
Return True
Else
Return False
End If
End Function
Now I want to use is TrueForAll method of Generic list. How can I use it ?
If there was No second Parameter in IsMatching method, I could have simply used
myList.TrueForAll(AddressOf IsMatching)
But since there is a parameter strMyString, I dont understand how can I use IsTrueForAll method. How can I use IsTrueForAll method in this scenario.
I have had several occasions recently to access a specific class several times over a relatively small time frame.So I've been storing the value of the class in Session and trying to access it on page load, if it's not available creating a new instance and storing that in session.
So instead of constantly replicating the same code for different classes on different pages I'm trying to create an extension method to do this for me.
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I'm stuck on what to do when I make my new instance of my class (it would have to have a New() sub)
I'm not sure where to go from here... or even if this is the best way to do it.
Currently my code has the following properties:
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I have a problem with the VB.NET compiler failing to compile a class (in a separate C# assembly) which contains two overloads of a method with generic arguments. The equivalent code in C# compiles against the same assembly with no errors. Here are the two method signatures:
protected void SetValue<T>(T newValue, ref T oldValue)
protected void SetValue<T>(T? newValue, ref T? oldValue) where T : struct
Here is the code to three assemblies that demonstrate the problem. The first is the C# assembly with a Base class that implements the generic methods. The second is a C# class derived from Base and calls both overloads of SetValue correctly. The third is a VB class also derived from Base, but fails to compile with the following error message:
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Am I doing something wrong in the VB code, or are C# & VB different when it comes to generic overload resolution? If I make the method arguments in Base non-generic then everything compiles correctly, but then I have to implement SetValue for every type that I wish to support.
After looking at this thread.>>
How to randomize the alphabet I have decided to make it into an extension method for a String and a List.
Note: Please see the following post if you are still using VB.Net 2002, 2003 or 2005
this code is for use with 2008 and later versions of VB.Net
String.Mix and also List.Mix I was trying to write a generic extension method for every Enumerable(Of T)
I settled on just doing it for a STRING
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I will try to explain what I need.Let's say that I have a class like this:
Public Class Example1 Public Sub ToBeCalled()
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Getting this error message and I am not able to figure out why. Here is my code:
<asp:TextBox ID="searchParam" Width="250px" runat="server"></asp:TextBox><asp:button ID="btnSearch" runat="server" Text="Search" />
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="getCOMDLs" TypeName="NewEmployee">
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I have 3 similar functions, that only change based on numeric type:
<Extension()> _
Public Function ToNullableShort(ByVal str As String) As Short?
Dim intReturn As Short
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I was trying to make a generic function out of this, but couldn't do it. How can I make a generic function that will take a specific T and make it a Nullable(of T)?
I have a custom list that inherits Generic.List and it has a method for deselecting all of the members named DeselectAll It has looked like this for a few weeks and has worked fine.
Public Sub DeselectAll()
MyBase.ForEach(Function(p As Publipostable) p.ModeEnvoiChoisi = Nothing)
End Sub
Today, it stopped working ?!? I reverted to an earlier version using delegates and that works fine...
Public Sub DeselectAll()
MyBase.ForEach(AddressOf DeselectModeEnvoi)
End Sub
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Edit: Stopped Working meaning it no longer sets the property p.ModeEnvoiChoisi to Nothing on each item in the list. The DeselectAll method gets called, but all the items retain their previous values...
I'm trying to search a generic list of 'User' business objects which has a property called 'Username': If (From u In colUsers Select u.Username Where Username.Equals(strUsername)).Count > 0 ThenI keep getting:Delegate to an instance method cannot have null 'this'.
View 16 RepliesBase 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.
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I have a large problem with inheritance in vb.net. The problem is the following:
I have 2 forms => frmBase and frmChild
In frmBase i want to create a method Called StartWorking() and i want frmChild to inherit this method.
But here is the tricky thing: when frmChild.StartWorking is called i would like the following => without calling MyBase.StartWorking()
I want frmBase.StartWorking() to be executed first and after a test in frmBase.StartWorking if blnValue is true then frmChild.StartWorking has to be activated. if blnValue is false that frmChild.StartWorking cannot be activated.
Supose a base class
Public Class airplane
Private var_num_seats As Integer
Private var_num_engines As Integer
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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)?
class
eg: dim classobj = xyz("CLASS_NAME") ' where classname is a valid class name
and dynamically raising a known method of that class on that newly created object or class reference.
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I need to have a dynamic URL preferably from a Test Classformatting this design pattern to handle dynamic links from tests. instead of a constant HomePageURL.
Namespace TestDesign
Public Class HomePage
Inherits IE
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