[2005] SyncLock And Multithreading - Public Class Utilities With A Many Shared Functions
Feb 11, 2009
I am trying to get a handle on SyncLock and multithreading, but I am having some trouble wrapping my head around exactly how it should be implemented. I have a Public Class Utilities with a many Shared Functions. I want to make sure that each function can only be executed when there are no other concurrent calls to the same function. So If I have 2 functions, A and B in a Public Class Utilities, what is the syntax so that a function "locks" while it is being executed, preventing any subsequent calls until the "locking" thread has completed?
CODE
Public Class Utilities
Public Shared Function A (ByRef i As Integer) As Integer
[CODE].............................
I know I need to wrap the statements of execution in a SyncLock block, but I am unsure of the scope of the parameter used with SyncLock...is it private to the function, class, etc? Can the same object be used to lock both functions if they are independent?
View 36 Replies
ADVERTISEMENT
Dec 6, 2010
What I am trying to do is have a class where the functions of the same name are both instance functions and shared functions.
Public Shared Function Get...(byval xx as xx)
and
Public Function Get...
The Public Function uses a Property xx created in the constructor, whereas the Shared Function has the parameters (byval xx as xx).
View 1 Replies
Feb 10, 2011
I can access a module from code behind but not from the aspx page in inline VB code <% ... %>.
View 2 Replies
Jan 29, 2010
I have an asp.net web app. It has a shared class, and I want to have the connection string the same through out the site. My string is in my web config, but I don't want to type this all over the place:
View 3 Replies
Jul 22, 2009
give me a good resource that explains the difference between a Private, Public, Shared Functions/Sub/Variables? I normally use Public for Subs/Functions inside of Modules I call from other parts of the program. But I'd like to get more of an understanding of how and when to use them. I want as little as impact to a system that is running my programs as possible, so i guess the key here is I'm trying to just get more proficient in my coding.
View 8 Replies
Feb 11, 2009
I have large group of functions that I would like to store in basically a library and simply call the functions from the controls on my forms. Back in VB 6 I would have done this with a module, but now I have been told that a Public Class is the correct way in .NET. How should I go about doing this?
View 2 Replies
Jan 10, 2012
I currently have two forms, and I need to share the value of a variable in one of them.
I declared the variable to be 'Public Shared', and assigned a value to it. However,
when I inspect the value it appears as 'Nothing'. Here is the snippet:
Public Class A
Public Shared sVar As String = Nothing
Private Sub A_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[Code]....
View 4 Replies
Oct 8, 2010
Can we override a Public Shared method in derived class? If not why?
View 2 Replies
Aug 9, 2011
I would like to understand the Pro & Cons in using the commonly used methods via Singleton class against Shared (Static) members of a class in VB.Net. It could be in terms Time, Space complexity or best practices. I have a BankAccount class with methods doing some business logic.
GetBalance()
GetLast5Credits()
GetMiniStatement()
[code].....
View 4 Replies
Apr 22, 2010
I've got a BaseDataClass with shared fields and functions
CODE:
I have several classes that derive from this base class. The derived classes have all Shared functions that can be called directly from the BLL with no instantiation. The functions in these derived classes call the base Init(), call their specific stored procs, call the base CleanAll() and then return the results.
So if I have 5 derived classes with 10 functions each, totaling 50 possible function calls, since they are all Shared, the CLR only calls one at a time, right? All calls are queued to wait until each Shared function completes.
Is there a better design with having Shared functions in your DAL and still have base class functions? Or since I have a base class, is it better to move towards instance methods within the DAL?
View 1 Replies
Apr 21, 2012
I am just testing how to use dll and after googling a lot, I made it work partially...Created new project Class Library, named it myFirstDll and made a Public Shared Sub helloDll to do something. Now since this is my first time, the dll is simply showing the input in a msgbox:
Public Shared Sub helloDll(ByVal msg As String)
If msg <> "" Then
MsgBox(msg, MsgBoxStyle.OkOnly, "WE HAVE SOME MSG")
Else
MsgBox(msg, MsgBoxStyle.OkOnly, "NO MSG")
End If
End Sub
After building the dll-file, I started a new project using normal windows forms, named it "useMyDll", I clicked Project -> Add Reference, and added my dll. The program file that I made needed a textbox and a button for using the dll:
Private Sub useDllButton1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles useDllButton1.Click
Dim msg As String = Nothing
msg = TextBox1.Text
myFirstDll.myFirstDLL.helloDll(msg) 'this will be in msgbox in dll-file
End Sub
And when running this I could write something in the textbox and a msgbox with that input would pop up. Really happy with that. My first attempt to make a dll and use it was very successful. Then I thought, what about running the dll from rundll32.exe? It would be handy to make a dll that could be run without my exe. After googling a long time, I tried to add a new button:
Private Sub useDllButton2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles useDllButton2.Click
'Now let us see if we can open it using rundll32.exe ?
Dim msg As String = Nothing
msg = TextBox1.Text
[CODE]...
Now the first button still works just fine, but the second button gives some error (translated to english would be) like "missing entry: helloDll" I also tried to open with command prompt, same result.
After googling again I read one place that you can't run a visual basic dll with rundll32.exe, so is this true? Or is there some way of doing it? I read one place that it works if you make the dll be "COM-Visible", but I don't really understand how to or what it means. I tried to open properties, clicked Assembly Information, and "Make assembly COM-Visible", but this doesn't change anything. Then I read somewhere that it has to be in a module to work. Could it be that I need to rewrite some codes and it would work, or would I have to start learning c++ in order to accomplish this?
View 13 Replies
Jan 31, 2011
i have some test code which i run at every load of a page in my asp.net website [Code] the "dotrace" simply add a record to a log table in the db. now the right result would be that i should have the entries in the db in order "entered","exiting","exited" but actually when i look in the db i see first 2 "entered" then 2 "exiting" etc. meaning that the multi-threading is working ok, but not the synclock. is that correct?
and how can this be fixed? the real code will be adding records to the db and might be called from several pages of different sessions, but the same code must not run twice concurrently. if i open multiple pages at once, they still clash some times. but if i'm correct, the issue is now not with the synclock as much as with the httpruntime.cache, because when using a standard property, on one page, the code works 100%. so how can i make sure that 2 threads, even from totally different sessions never run the trylock simultaneously?
View 1 Replies
May 28, 2012
I am pretty new to multi-threading in general and I would like to know how can I lock a shared integer variable to not be accessed by other threads while it is read/updated by an other thread.When I try do do SyncLock myInteger, I get that error : Error 6 'SyncLock' operand cannot be of type 'Integer' because 'Integer' is not a reference type.
Here a simplified example of what I mean
Private Shared myInteger As Integer
Private Sub MySub()
SyncLock myInteger ' This does not work
' read/write a new value to myInteger
End SyncLock
End Sub
MySub is called by multiple instances of the class, and running in multiple threads?
View 1 Replies
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.
View 1 Replies
Mar 30, 2012
I've taken over the maintenance of the website (ASP.NET VB) and on one particular page I noticed the below code
Inherits System.Web.UI.Page
Public Shared UserNumber As String
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
[Code]....
My question is whether the variable UserNumber can be accessed or changed by any other user than the current one?
View 2 Replies
Jun 13, 2009
What does the "where T : new()" do? VS 2005 public class TestClass<T> where T new()?
View 1 Replies
Jun 4, 2010
I am trying to add shared members in derived classes and use that values in base classes...
I have base
class DBLayer
public shared function GetDetail(byval UIN as integer)
dim StrSql = string.format("select * from {0} where uin = {1}", tablename, uin)
end function
end class
[Code]..
currently there is error using the tablename variable of derived class in base class but i want to use it i dun know other techniques if other solutions are better then u can post it or u can say how can i make it work? confused...
View 2 Replies
Jun 30, 2009
if it is possible to place the openfileDialog in public class or module? i tried to place it with this code, but it did not work.
Public Sub DisplayDataOnGrid(ByVal gridTable As DataGridView)
Dim filepath As String
Dim OpenExcelFile As New OpenFileDialog()
[Code]....
View 2 Replies
Feb 27, 2009
I understand how the class modifiers work like public, private, protected, friend and protect friend. They are pretty straight forward. However my question is, if I have a class is marked as friend, what should the properties and methods be marked as? Friend or public? Does it matter? I just want my classes at the lowest exposure level that will let my program work properly and that is friend. If I understand correctly, the public properties of a friend class are available to all members of the assembly. Wouldn't that be the same access level if the properties were all friend properties?The reason that I ask is that using the autocomplete feature to make new properties (type property and hit tab) it creates the new properties with the public attribute.
View 4 Replies
Apr 23, 2012
Public Shared _formRef As frmMain
Public Shared f As frmMain
Class Server[code].....
but once firing off the code i get the error you see in my image attached.
View 1 Replies
Feb 24, 2012
I've got 4 projects all running very similar multi-threading HTTPListener stuff.I wanted to make these functions common - in some module - but I'm having a hard time getting the AddressOf the "callback" passed in.This was the code in one of the 4 projects
Private Sub StartRequests(ByVal prefixes() As String)
If Not System.Net.HttpListener.IsSupported Then
DisplayInfo( _
[code].....
View 1 Replies
Oct 3, 2011
I have an application that queries DHCP and pulls scope/subnet information. There are roughly 8k scopes on our network to query so reporting this data takes a little bit of time. I currently have this running on it's own thread and reporting to a progress bar so the applications doesn't seem inactive.
The DHCP api functions can report a total, a max read and a resume argument. This means that I can, in theory start 4 threads and have each thread read through 2k subnets, so it will only take 1/4 of the time to read all this data. Would I need to create four separate background worker handlers, do_works, runworkcomplete, report progress etc.?
View 3 Replies
Apr 7, 2011
Imports System
Imports System.Threading
Imports System.ComponentModel[code]....
how to declare "smsport" on class smscomms as public so that it can be access in class form1 or button1_click event.
View 5 Replies
Jun 29, 2011
I have an arraylist in a user form (Mainform) that I would like to be able to share among multiple forms and edit the contents. Using the Public Shared method I have been able to view and even edit the arraylist, but it does not seem to be changing it back on the main form. I can give more detail if needed.
View 9 Replies
Jun 6, 2009
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.
View 3 Replies
Jul 31, 2009
I am working with VB.Net and am kinda new. I was wondering, if my asp.net project has a lot of shared functions, can I put them all into one Namespace? Do I have to put them into a class?
View 7 Replies
May 21, 2009
I was wondering how to implement a vb script file with functions and subs that can be used in all code pages of a project. Similar to the old VB 6 bas files.
View 2 Replies
May 21, 2010
I've created a global sqlConnection in my app and it works fine for sharing the connection between functions. I have also defined a global sqlTransaction that I'd like to share between functions also, so I don't have to pass it around during a complex update but it's not working as I hoped.
Module Master
Public sqlConnString As String
Public SQL As String
[Code]....
View 7 Replies
May 13, 2011
Example:
Two files - TestClass.vb, myForm.vb
TestClass.vb looks as follows:
Imports System.Threading
Public Class TestClass
Private myClassThread As New Thread(AddressOf StartMyClassThread)
[code]....
The result:Application runs, no errors or exceptions.Displayed is the listbox and the Start button.I press the start button and a msgbox says "Not Invoked" as expected and upon clicking OK to that msgbox "Start Button Pressed" is added to the Output listbox control.Immediately following that the msgbox pops up again and says "Not Invoked". I was expecting "Invoked" as a separate thread is trying to use the Output listbox control.Of course this results in the Output.Items.Add being attempted which results in no visible result as the thread is not allowed to directly update the UI control.
View 1 Replies
Aug 6, 2009
I made the changes from this:
[code]...
to this:(the 'End Function' says "Function 'GetFolderPath' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used."
[code]...
View 4 Replies
