Local Variables In Shared Method Work Like Static Variable In C?
Aug 23, 2011Will the list in this shared method keep its state throughout the life of the method? Or will a new list be created every time this method is called?
[Code]...
ADVERTISEMENT
Difference Between Static And Shared Variables In .NET?
Jun 22, 2009exact diff b/t Static v/s Shared variables in VB.NET?
View 3 RepliesGenerate A URL Within A Shared (static) Method In MVC.NET?
Sep 27, 2009I'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.
View 1 RepliesC# - Shared / Static Variable Should Be Nothing?
Jan 6, 2011I have the following code:
Public Class TestClass
Public Sub Main()
If theGlobal IsNot Nothing Then Throw New Exception("What gives!")
End Sub
Private Shared theGlobal As Object = Nothing
[Code] .....
Why is theGlobal object NOT Nothing?
Asp.net - How To Get Classes To Expose The Same Shared/Static Method
Mar 4, 2010I 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?
View 3 RepliesUse Of Static Local Variables In Lazy Loading Property
Sep 19, 2011I just recently learned about the uses of static local variables in VB.NET and wondered about it's potential use in lazy loading properties.
Consider the following example code.
Public Class Foo
Implements IFoo
End Class
[Code].....
As far as i can see, this has a few advantages over the usual implementation, primary your inability to access the variable outside of the property, as well as not having to use an additional variable.
My question to you is: Which of those is the "right" way to do it? I know that static variables have additional overhead, but is it bad enough to create, in my personal opinion, unclearer code that can be misused easier? How much performance do you lose compared to the "traditional" method? How does it matter for small classes compared to huge factories?
.net - Prohibit An Instance From Calling Shared/Static Method?
Aug 27, 2010Is 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.
C# - Access A Shared/static Member Through An Instance Variable?
Mar 3, 2011Here'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.
Local Variables Are Automatically Shared
Mar 13, 2012I was reviewing the MSDN documentation on VB.Net's little-used Static keyword for local variables. My question is not about how Static works (I personally plan to avoid using it as it seems like it could cause grief to future programmers who don't notice the side-effects.) My question is about this statement in the docs:[code]So can anyone interpret the above statement for me in a way that makes sense? Or is this a bug in the documentation? It's been there since the VS 2005 version of the docs and is still present in the Visual Studio 11 version.
View 2 RepliesPrivate Shared Variables Vs Local / Namespace Performance
Jun 8, 2009I came across a number of new Private Shared variables (of type Hashtables(Of String), initialized in the declaration) added to a partial class for a very large (DataContext-derived) class. This seems sensible to me in one sense because they never change, and making these shared variables ensures that they won't get re-initialized every time a function is called. However, these variables are only used within the scope of one function in the class, and I fear the private namespace of this DataContext-derived class is getting rather polluted, and having these sorts of things exposed at such a high level might be confusing to others reading the code in the future.
Would there be negative performance impact to making these local variables within the function where they are used, or is there some better way to handle this? Basically we are using these 3 hashtables to determine whether anything within particular subsets of properties changed (using GetModifiedMembers and then using the Overlaps function of the hashset to see if any of the modified members correspond to members we care about).
Edit: I caved and took the time to write my own test program, which confirmed that there is a cost to using local variables (which I assume applies generally to all cases -- I doubt there's any case where a shared variable would be slower unless using the shared variable requires some additional logic to do so properly): [Code]
So in this particular case, using the local variable costs about 200%. But in most cases (including my own), the time is probably negligible compared to the overall task. So I guess the question now becomes, how do people generally feel about improving code maintainability at the cost of negligible but known performance impacts?
VB 2008 Why Are Static Variables Set Equal To 0 In The Declaration When 0 Would Be The Default Value Of The Numeric Variable
Apr 21, 2010Why are static variables set equal to 0 in the declaration when 0 would be the default value of the numeric variable anyway when it's first declared? Not including the "=0" in the static declaration seems to work with no problem.
View 2 RepliesWhy Doesn't XmlSerializer Work For Shared Class Variables
Dec 8, 2011I have the following class which I want to serialize to XML:
[Code]...
Asp.net - Local Static Variables In Timer.Tick Event (Stopping A Timer)
Jul 9, 2009I have a timer on a page in ASP.NET.
After a certain period of time elapses, I want to disable the timer.
I want to put a static variable in the timers tick event that will track how many seconds have elapsed.
My question is, will this work?
If user X and Y are viewing the page will they both have separate local static variables?
What is the best method of shutting down an ASP.NET timer after a certain elapsed time?
Statically Type Local Variable To Be Static Type Of Expression On Right Had Side Of Assignment?
Dec 22, 2009E.g. how do I get VB.Net to statically type a local variable to be the static type of the expression on the right had side of the assignment?
View 1 RepliesAccess A Class Variable Inside Shared Method (JSON)
Jun 20, 2012Inside my .aspx I have some JSON code that looks like this:
[Code]....
Basically what I'm doing is pulling text from two labels on one page, and sending them to another page by calling the "doIt" function which looks like this:
[Code]....
Just so I'm clear, the "doIt" function and the JSON call are on two separate web forms. My problem is that with the "doIt" function being Shared, I can't access any global variables of the class. And if I remove the Shared, my JSON doesn't execute.
Should A Local Variable Call Dispose Method And Set To Nothing?
Oct 14, 2009I have 2 question, hope somebody give me an explanation: 1. Should a local variable call dispose method and set to nothing? 2. If some method have an arguments which it is a ByVal argument, it means a method create a new object? But If it is a ByRef argument, it means a method don't create a new object?
View 4 RepliesUse Variables Or Properties, And Global Or Static Variables In A Class?
Jun 9, 2012I'm new in .NET programming.I have a class Form1 that includes Button1_Click event.Button1_Click creates a multiple Text Boxies at run time)Here is the class:
Public Class Form1
Dim shiftDown As Integer
Dim counter As Integer
[code].....
.net - Why Can't Call Private Shared Methods From A Public Shared Method
Aug 25, 2011I 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.
C# - Reset A Static/shared Class?
May 4, 2009I've got a shared class (static in C#) which mostly carries some settings data that any class in the application can read and sometimes write. Also there are some static properties which holds some internal states.
Now I want to revert this class to initial stage of it. With all default variables etc. Assume that the user want to reset the current state and start over without restarting the application.
In a singleton model I'd simply renew it with something like this :
Public Sub Reset()
_Instance = New MyClass()
End Sub
However this is not possible in a Shared class. Or should I switch back to Singleton?
C# - Static (Shared In VB) Or Normal Methods
Oct 27, 2009I Want to know which one is preferred while coding to use Static Methods or normal instances, I prefer to use static if they where few but if there was many of them I start to get some doubts
[code]...
if the EmployeeManager Has Many methods (selects deletes updates) is it ok to make them all static.and if it was Normal instance. wouldn't be a drawback if the object is initiated every time specially if GetAllEmployees() is heavily used.What is the better approach to use?
LoadControl In Static / Shared Function
Dec 30, 2009how I can dynamically load a control inside of a shared/static function?The function itself is inside of a mustinherit/abstract class.(It's an ASP.NET project in VB) I want to do something like this:[code]I'm getting "Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class.",but I don't understand this error.I understand what it means, I just don't understand why calling LoadControl isn't seen by the compiler as being an explicit instance of the class. What's not explicit about using LoadControl to create a new control from a file? I tried creating a new user control and initializing it, then setting it to a different control with LoadControl to no avail.I also don't want to do a DirectCast because I'm trying to put this in a shared, mustinheret (abstract) class, which therefore doesn't have an .aspx file to write in a <%@ Reference Control="~/SomeControlPath.ascx" %>, so the class name is unavailable.What I'm trying to do is write a static function that takes some value and returns a control based only on that control's source file location.The end result is a user-modifiable list of controls.They get a column of controls that they freely add, remove, or reorder based on a static list of available child controls that I specify.
View 4 RepliesPossible To Have A Shared/Static Dependency Property?
May 25, 2010[using VB.NET, but I can easily read C# code in responses]I have a class called QuestionClipboard with ALL shared methods/properties. I previously had a QuesitonClipboard.doesClipboardHaveContent function that returned true/false if there was a Object on my 'clipboard'.I'd prefer to implement a Dependency Property so I can allow this true/false value to participate in data binding.The "GetValue(dp as DependencyProperty)" method requires an object instance, which would mean that my Property CAN'T be shared!Here is what the code would look like in my perfect world... Of course, the word "Shared" before the property declaration renders this code useless.
Private Shared clipboardHasContentPropertyKey As DependencyPropertyKey = DependencyProperty.RegisterReadOnly("clipboardHasContent", GetType(Boolean), GetType(QuestionClipboard), _
[code]....
Shared (Static) Classes With Events In C#
Mar 27, 2010[code]Now how do i do this in c#. I know there is not handles clause in c# so i need some function that is called and assign the event handlers there. However since its a shared class there is no constructor i must put it somewhere outside of a function.
View 2 RepliesVisibility Of Static / Shared Members
Dec 30, 2009I have faced with a situation in VB.NET and C# (.NET2) with the visibility of the static/shared members. It seems to me a little strange in VB.NET:
public class A {
private static A instance;
public static A Instance {
get { return instance; }
} public string Name { get { } }}
[Code] .....
Shared member behaves like a class public one I can repeat it to infinite..
Asp.net - Calling Other Functions From A Shared (or Static) Function
Aug 20, 2010I get this error: Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class.
Partial Class _Default
Inherits System.Web.UI.Page
<WebMethod()> _
[Code]....
I know it has something to do with the fact that the first function is shared and the second function should probably be Public as well but I don't fully understand the reason behind it. Probably not relevant but I'm calling the web method from some javascript.
C# - ASP.NET's App_Code Folder And Shared/Static Classes?
May 15, 2011If I have a 'Shared' object defined in the App_Code folder; is that object shared amongst all users/visitors of my website? Or is it shared on a per-user basis?I don't know if that makes sense or not; but I've got a puzzle/solver I'd written earlier that I'm trying to incorporate into a simple ASP.Net site. It's probably poorly written, but I'd used a Shared boolean to determine if a solution had been found. The code works, now as an ASP.NET site, but if two visitors to my site were both validating their puzzle at the same time, would they both be accessing the same boolean?
View 3 RepliesC# - Best Practice For Complex Shared / Static Members
Sep 7, 2011I took over an ASP.NET application and have found this throughout several classes in the application. The programmers before defined several shared/static variables that act as "complex enums" throughout the application. As a fairly new programmer, it doesn't look like best practice.
Here is an example:
Public Shared SecureCommentsWrite As New Task("Secure Comments Write")
Public Shared SecureCommentsRead As New Task("Secure Comments Read")
Public Shared EditEmergencyContact As New Task("Edit Emergency Contact")
Public Shared DisplayPersonalReferences As New Task("Display Personal References")
Public Shared EditPersonalReferences As New Task("Edit Personal References")
The constructor takes the description, then loads the ID key from the database using a stored procedure (the database is SQL Server.) This seems like a good idea since we deploy this application to multiple databases and want to ensure that we load the ID key that's in that database in case it changes. However, since there are literally hundreds of these in the application, the first load takes a while.
C# - Why Only Static / Shared Version Of ForEach For Arrays
Aug 18, 2011Why there is only a static/shared version of ForEach for arrays?
IE: ForEach<T>(T array[], System.Action(Of T) action[])
I assume this has something to do with the type inference requirements of implementing an instance method, but when you declare your array you provide type right?
Shared Method Not Calling Shared Constructor
Aug 12, 2009Given 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]...
View 2 Replies.net - VB Cross-thread Shared (static) Member Access?
Aug 4, 2010I'm a newbie to threading, trying to learn it as I go. don't make any assumptions and try to explain threading concepts and rules that might seem obvious. I have a Module (Static class) as follows:
Module Main
Private ReadOnly _dbConn As SqlClient.SqlConnection
Public ReadOnly Property DBConn() As SqlClient.SqlConnection
Get
Debug.Print("Accessing DBConn")
[Code]...
All throughout the application, when i access DBConn on the same thread, it works as expected. howeve, later on I created a background worker that tries to access DBConn and nothing happens, the thread just hanges (the Background worker). I dont get the printout and the application doesnt continue. the background worker thread doesnt continue past that point, and so the thread never exits. I dont get any exceptions, and i Cant debug in Visual Studio (visual studio hangs).I guess its a 2 part question: why cant i access DBConn from the other thread, and why does it hang without giving me a threadAccess exception? also, why does visual studio hang (I'm assuming it hanges because the thread is hanging)?
Please Note: I am not asking about practice. I know I shouldnt be sharing the same connection, rather returning a new connection. in this particular application it is safe since (although i execute it on a background thread) as per the flow of the application, the connection can only be accessed one at a time. I just want to know why it hangs accross the thread.