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'm looking for a the shortest/aseist way in VB.NET (or C# but using VB.NET at the moment) to get the string value of a method's name dynamically given the method call.For instance, I have a class like this:
Public Class Blah
Public Sub Foo()
End Sub
End Class
Now Foo is a strongly-typed cover for a dynamic setting and I have an event handler that will fire when the setting changes and return the string name of the setting that changed.
I'd like to be able to switch/select on this string and have a case based on the Foo() method. To do this I need to able to get the string name of the Foo method from the method call itself (i.e. somehow GetMethodName(blahInstance.Foo())).
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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Write an overload for every numeric type or if possible constrain a generic extension method to just numeric types.
View 2 RepliesI have a class which i realized will not always correctly instantiate and as a quick fix, i figured i'd subclass it and shadow a few methods so that the program can continue to run without exploding. When i run the software, calls to the methods resolve to the base's implementations and not the subclass. I'm using VB.NET with .NET 2.0. Here is an example of what i'm trying to do[code]....
View 1 RepliesI 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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REF: http:[url].....The above reference is where I got the code below.This code adds buttons to Form1. When a button is clicked a messagebox appears stating what button was clicked. I want to have the ClickHandler fill a RichTextBox on Form1 (I added a RTB to Form1). My problem is I can't do a Dim xForm As New Form1 to fill the RTB from the ButtonArray Class. I can place my file's text in a MessageBox so I know the code I added is correct. I also tried placing a Property method on Form1 and using a Accessor to fill the RTB, however it also requires Dim xForm As New Form1. How can I get my data from files to the RichTextBox on Form1 from the ClickHandler in the ButtonArray Class? See ButtonArray Class Below.
Imports System.IO
Imports System.Text
Imports System.Collections.CollectionBase[code].....
I 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 RepliesI 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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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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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.
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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)?
I am indifferent if you are a VB.NET or C# or other .NET developer. I have a FACTORY class like the following:
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I'm trying to code a class of RandomNumber. One of the class methods needs to populate a "List (Of RandomNumber)" ... which was passed as a parameter to the method ... with 10 random numbers between 1 and 50. DEAD SIMPLE :)
View 6 RepliesI have a copy function that I'd like to override in subclasses to return the type of the subclass. Here are my interfaces:
Public Interface IBase(Of T)
Function Copy() As T
End Interface
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Public Class notifierMain
Public Class Contacts
Inherits List(Of row)
Public Sub New()
[code]....
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?
Does calling the Dispose method on a Windows.Forms.Timer call it's Stop method? Or should I stop the timer before I dispose it?
View 5 RepliesI 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.
I have nine pictures that I need to animate -I need to use the ToString method and a counter to concatenate a file name into a string variable from the Image.FromFile method. Once the counter reaches its maximum value, and the last picture is displayed, the counter should be reset to zero or one depending on how the first image file has been name. Also a static counter variable should be incremented in the time routine. what I have so far -- I know what I have to do; however, I just do not know how to code this properly.. Right now I have this going thru a button procedure but it needs to go through a timer.
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I just need to know what is the slight difference between them so I know which one to use everytime.
View 5 RepliesWhen I am loading an Assembly dynamically, then calling a method from it, I appear to be getting the method from Assembly executing before the code in the method that is calling it.It does not appear to be executing in a Serial manner as I would expect. Can anyone shine some light on why this might be happening. Below is some code to illustrate what I am seeing, the code from the some.dll assembly calls a method named PerformLookup. For testing I put a similar MessageBox type output with "PerformLookup Time: " as the text. What I end up seeing is:
First: "PerformLookup Time: 40:842"
Second: "initIndex Time: 45:873"
Imports System
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Why does my the declaration of my string in the code result in the following error? Is there a workaround?
Code:
<script runat="server">
Protected Sub form1_Load(sender As Object, e As System.EventArgs)
Dim x As String = "</script>"
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Error: Statement cannot appear within a method body. End of method assumed.
Note: The following page did not fix my issue and instead resulted in the string </script> being output in my page. ( VB.NET hates </script> tag in string literal )
I am not sure whether this is a trick question?One of the object i have has 2 boolean properties, Standing and Sitting.I have a class called student with the 2 methods stated below- Am I coorrect is assuming that the first method draw() is affected by the standing property AND not the second method?Also the way it affects is that it draws an image when the the stugent is standing?
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What's the equivalent method in .NET of the Picture1.Scale (0,0)-(10,10) method in 6.0?
View 2 RepliesI just have a short question about adding an destination methode as variable argument into my calling methode.
I want to send a "TextChanged" event to a special textbox. But I want to have a "variable" in my methode to add the handler to the textbox. Because it is possible to change the textbox and then I can change the handler where the "Changed Events" should be routed to.
can you replace the questionmarks below??
Dim TextBox1 as TextBox
Dim TextBox2 as TextBox
Private Sub DoIt
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I have some code in c#
BeginInvoke(new MethodInvoker( delegate() {myAppMethod_Tick(sender, e); }));
Now, When I tried to convert that code to vb.net I have below..
BeginInvoke(New MethodInvoker(Function() Do myAppMethod_Tick(sender, e) End Function))
But it does not compile.. What's problem for it?
Because my c# application works ok without any problem..
Let's say I have a page Test.aspx along with test.aspx.vb.Test.aspx.vb contains a class name "TestClass". In that class I have method1(), method2() and method3()I need to be able to call one of those methods, but I can't hard code it, the method to be executed comes from a string.
I can't do
Select Case StringContainingTheNameOfTheDesiredMethod
Case "Method1"
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Extension methods are useful for types that you don't own and can't/don't want to derive from and extend (e.g. reference types and interfaces). Obviously, interfaces should be kept as short and to-the-point as possible, so extension methods for interfaces are particularly useful (e.g. LINQ).For classes, especially classes that you own, they're still useful - but I'm wondering how you determine what should be an extension method or what should be a method in the class itself.Personally, every time I think about it, I keep going round in circles with the following thoughts:If it's useful enough, it should be in the class.It's not part of the core responsibility of the class, it should be an extension method - but if it's useful enough, surely it should be the responsibility of the class...
View 3 RepliesI have a Application that Crypts all Files in a Directory and the Subdirectories
Public Shared Sub CryptAllFiles(ByVal crypt As Object)
'check if this dir exists
Dim vDirInfo As New DirectoryInfo(vPath)
If Not vDirInfo.Exists Then Exit Sub
'get all files' sizes in current path
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