Moving Large Instance Method To Shared And Creating Stub?
Jun 5, 2011
If I have a very large function/sub in a class that is an instance method (i.e., not Shared), do I gain or lose anything by moving that to a shared method and then declaring a small stub method for the instance use?
I.e., I go from this:
Public Sub MyBigMethod(ByVal Foobar As String)
If String.IsNullOrWhitespace(Foobar) Then
Throw New ArgumentNullException("Foobar")
End If
[Code] .....
My thinking is I save on memory size per each instance of the object. Because each instance only has to lug around the stub method which handles calling the shared version and passing an instance of itself to the shared method so that it can do whatever it needs to do. But I'll wager that I sacrifice a very teensy amount of speed because of the added function call overhead.
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Nov 4, 2010
I have been thrown in at the deep end with an existing VB.NET project at work. I have never used VB.NET before so I am struggling a little. Does anyone know how to solve the following.I need to pass an instance to client side and then pass it to a shared method in order to access instance methods from when the shared method.The starting point is a fileupload control within the HTML of my Contacts.aspx file:
<asp:FileUpload ID="DocUpload1" runat="server" onchange="CallMe();" />
The onchange event calls a javascript method, see below, this uses AJAX PageMethods to called a Shared method in my code behind This is the script code which is in my Contact.aspx file
[Code]...
If anyone knows the solution please could they update the code as I probably won't be able to understand if you just give a description. I just hope I am along the right tracks.
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Feb 13, 2012
I would like to create a global instance of a User Class that can be referenced by all the forms in my MDI application.This object may be set during the login procedure by the Login form but the user attributes are to be available for other forms. For example, MyUser.ID will be required for meeting the audit requirements whenever data is changed.
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Aug 27, 2010
Is it possible to prohibit an instance of a class from calling a shared/static method?
For example:
I want to allow this:
ClassName.MethodOne()
But I want to disallow this:
Dim A As New ClassName
A.MethodOne()
The reason this is desirable is that in this case it is semantically confusing if an instance can call the method.
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Aug 25, 2011
I have a class like this:
[Code]...
It works, when I make getBar methods public, but I don't want to expose these unneccessarily. Why I can't call private shared methods from a public one in the same class is over my head. I'm using .net framework 4.0 in a web application.
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Aug 12, 2009
Given in the following language specification, for me at least, calling Db.Foobar() [In the following code] does not indeed call off to the Shared Constructors of the base classes. I am curious as to a) is this my own fault for doing something wrong or b) is this an error in the language specification[code]...
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Feb 28, 2009
I have one panel, and on that one picturebox with large image, so panel shows scrollbars.Now I am adding one picturebox to that picturebox (which is on panel).And when i move the added picturebox, it looks like, it is resizing the image of picturebox.Actually it is not resizing, but it seems like some barrier or something like that, or may be it is delaying in assigning the new position to picturebox. Additionaly, it works well with all other controls, just picturebox with image creates this kind of problem.[code]
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Aug 11, 2011
I'm working on a .Net Windows application. All the controls arrange fine, but when the user specifies their Windows display text to be larger than the Windows 7 default of 'Smaller', the controls get moved around on the form and makes it unusable.
Is there a way to lock down those controls no matter what the display text setting is at?
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Mar 3, 2010
As I stated before in my Sorting questions.When is it advisable to use Shared Functions vs Instance Functions References.The problem I posed was that in a threaded application if I was sorting an array of 999999999 elements I typically want to call a shared function that handles this; however in .NET the way to sort is through a .Sort method which you pass an array to be sorted and a function handler; or Comparisson(t of).
My impression is that if in order to do a ClosestToN Sort I would have to calculate the value of N in the array first; then sort and then subtract the value of N from the sorted array.JohnH suggested passing the value of N as a Property in a Class that contained a reference to a sort Algorithm.The benchmark suggested in a 1 thread model it would work faster (which I knew that it would through math, but the accessors I was speculative on; I turned out to be wrong it worked fine either way).
My issue is in a Multi-Thread application creating instances for an accessor may cause memory to fill quickly if I am dealing with 1000's of threads.Is it better in this case to use a slower Shared function, then a faster Instance Function?
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Nov 6, 2009
After I formatted my laptop and reinstalled Visual Studio 2005, I receive a lot of same error as below message.
"Access of shared member through an instance; qualifying expression will not be evaluated"
If I click the error, it direct me to the line and all 102 error suggest me to add "Windows.Forms." before "DialogResult.OK". Should I add something on "Reference"?
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Apr 7, 2010
How many instances of a shared variable will be created in a class? just one? correct
[code]...
So, in other words, the DocumentDelivery class will only have one instance of RenderList, correct? can somebody confirm?
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May 24, 2010
Suppose I have a class of objects called Porky with a property called IsHuge:
Public Class Porky
Public Property IsHuge As Boolean
End Class
Now I want to make a special kind of Porky -- let's call it UberPorky -- for which I want to change ALL instances to either IsHuge or not IsHuge. What I'd like to do is this:
Public Class UberPorky
Inherits Porky
Public Overrides Shared Property IsHuge As Boolean
[code]....
The trouble is, I can't do that. I'm not allowed to reference MyBase or Me in a Shared property.
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Aug 2, 2010
So, I have this code that grabs a bunch of data from the database, and performs a bunch of calculations on that data. However, this is not what is causing the halt. The halt is coming in when I take all that "final" data that has been prepared, and go to write that into a text file.
Each line in the text file is being created from data that has had calculations performed on it. Each line "corresponds" to a record from the database. A user will have to perform this file export usually on about 30-40 thousand records at a time. Now, even though I am using a StringBuilder, this still halts because of the pure mass amount of records.
What I do currently in the code is create one StringBuilder, append all the data (after calcs) to it, convert it to a String, add it to a List(Of String) to be returned from the Function, and then clear the StringBuilder, and do the same for the next row, and I do this until each row has been created and appended, converted, and then inserted into the List.
Then, another class receives this List(Of String) and takes each String and eventually appends it to a file.
Does anyone have an idea of how to improve this code and make it so it doesn't halt the server every time? The reason it wasn't found out until now is because when I tested it locally I was testing it on only 1-50 records at a time.
[Code]...
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Mar 3, 2011
Here's an example of what I'm talking about...
Public Class Sample1
Public Shared Function MyValue() As Integer
Return 0
End Function
Public Sub Code()
[Code]...
Me.MyValue gives a warning in VB.NET and (the equivalent code gives) an error in C#. Is there a particular reason for this? I find it more intuitive/natural to access the shared function using 'Me.MyValue' - but I avoid it to keep my warnings at 0. Did someone else just decide 'Nah, it makes more sense to do it the other way' or is there some technical reason I don't understand?
EDIT: I was thinking of it wrong, more like a 'sub class' in OOP. Even if something is declared in the base class, you access it through the instance you have. But that relationship is not the same with shared or static.
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May 14, 2012
I want to extend the BitConverter class with an overload of ToString() that takes a parameter of type Char, representing a value delimiter.Why? By default, the ToString() call returns a string representation of a byte array, delimited by dash symbols. The signature does not allow you to specify a different delimiter, which I find very unfortunate.Now because this is not an instance type, or maybe because I'm overloading a shared method, I'm having a hard time finding the proper syntax to define my extension method.What am I doing wrong here, causing the overloads to not show up in IntelliSense:
Imports System.Runtime.CompilerServices
Module BitConverterExtensions
<Extension()>
[code].....
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Oct 11, 2010
What is the purpose of using shared methods that return an instance of a class, as opposed to a constructor?
ie: in VB.net, the system.drawing.color class has shared method "FromArgb(int, int, int) as color". This is different from java's implementation which simply is a constructor that takes three ints. Why the decision to do one or the other?
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Dec 28, 2010
The context of this question is that I am trying to debug performance issues (apart from the obvious ones I already know about and can find).I inherited a code base (VB.NET) for an ASP.NET app. This is an app that was developed way back in .NET 1.1 days, and was the first .NET app for a lot of the developers who worked on it.
In this code base is a class called DatabaseUtility that contains several Shared Public methods as well as non-Shared Public Functions and Subs for CRUD operations to the database (SQL Server).
It is common in my "BL" that a method creates an instance of the DatabaseUtility which essentially figures out what the connection string should be and opens a connection, as well as giving the developer a handle to the other methods contained within it.Dim utility as New DatabaseUtility()
Once I have that, I start to create parameters that I am going to pass to one of the methods in DatabaseUtility (like GetDataSet). There is a Shared method in my DatabaseUtility called CreateParameter which does essentially that. It creates a SqlParameter object so I can add it to a Parameters collection.
Now, the code base is littered with a lot of this:
utility.CreateParameter(...)However, because CreateParameter is a Shared method, I am not sure what is going on behind the scenes. I know because it is a Shared member that an instance of the DatabaseUtility is not created when I call it like this:DatabaseUtility.CreateParameter(...)
However, because I am calling it from an instance (utility), does that change the behavior at all?
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Feb 8, 2012
creating single instance form in MDI Application. How to check whether form's instance created or not?
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Feb 28, 2012
As the question states, can a shared method of an object be multithreaded? I don't quite having threading down in my skillset, otherwise I would test myself. On the other hand, I am involved in designing class that could be part of a multithreaded application in VB.Net.
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Jul 7, 2009
I have a class that inherits from a base class (this contains a lot of common db related stuff amongst other things and is marked as MustInherit). I want to write a shared method in which I call a base class method, however the compiler gives me the message 'MyBase is only valid within an instance method'. This shared method is a logging method and will be used a lot within the app, I'm trying to avoid having to instantiate an object each time I want to call it.
Is it possible to access the base class methods from a shared method?
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Aug 26, 2009
I have a utility class that creates & returns a db connection:
Public Shared Function GetConnection() as OracleConnection
dim c as New OracleConnection()
... set connection string...
c.Open()
Return c
End Function
Is there any risk of concurrent calls returning the same connection? The connection string enables pooling.
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Apr 18, 2011
I have a new developer that is calling Showdialog (in VB.NET) on a Windows Forms form without first creating an instance of the form.How is this possible? I don't see a shared method for ShowDialog...
I'm not crazy about this approach either as it seems to me that the dialog will not be disposed until the application exits.What am I missing? Is this a new best practice?OK, Form2 is just a blank form.Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles Button1.Click
Form2.ShowDialog()
End Sub
End Class
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Sep 27, 2009
I'm creating a Shared (static) method in ASP.NET MVC so it can be used by any controller in my project. This static method needs to generate a URL. I think I need to use System.Web.Mvc.UrlHelper, but I can't figure out how to call it from within a static method.The constructor seems to want a RequestContext.
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Jul 24, 2011
I like to create an extension method to Image.FromStream Public Shared Function FromStream(ByVal stream As System.IO.Stream) As System.Drawing.Image
With possibility to cancel processing like Public Shared Function FromStream(ByVal stream As System.IO.Stream, ByVal CloseTask As ManualResetEvent) As System.Drawing.Image
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Dec 1, 2009
How can i use Server.MapPath in shared methos i tried something lile this [code]...
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Feb 8, 2010
[code].....
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Mar 4, 2010
I have a base class with several derived classes. I want all of my derived classes to have the same Public Shared (static) method with their own implementation. How do I do this? Is it even possible?
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May 8, 2012
[code]...
Dim ass as Assembly = Assembly.LoadFile("sample.dll")
Now, I want to call the shared method using the class name.
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Jul 31, 2010
use of the shared function, which returns a reference to a datatable to the calling code. While there a probably many debates as to the preferred use of ADO.NET objects, my question is about the Shared Method aspect. Note that the dataTable is declared within the Shared Function, so it seems to me you get a new one every time, yes?
Public Shared Function MyData() As DataTable
Dim ReturnData As New DataTable
'A silly example of retreiving some data into a datatable:
Using cn As New SqlClient.SqlConnection("SomeCOnnectionString")
[code]....
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Nov 21, 2010
There is a popup window which is rendered using xslt (no aspx page) on click of button, during this window load and close events I need to manipulate the text exist in the textarea of popup window. Having said I need to store the list words (key,value) for validation and spell check so I just declared a dictionary/hashtable object in common class (globals.vb) where i could store (add and retain values until I click close window, there could be couple of in turn calls to other methods of popup window) and manipulate as expected but whenever I reset the dictionary/hashtable (objDic.clear()) on popup load and close, it resets the concurrent users dictionary also.
Note :
1.Dictionary is declared as Public in Public Module (Globals.vb).
2.Dictionary manipulation happens inside the shared method (that is in turn calls to shared method of popup events).
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