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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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.
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.
How do I get using reflection the most generic type from a shared constructor in the base class :
Public Class Foo()
Shared Sub New()
'Here we have code to get the type[code]....
I expect the result to be Bar type and not the Foo. Is it possible?
I was looking on the interweb to see if there were any good examples on how to initialize shared members within a class while still initializing instance variables. I did find an expression that might fit to the answer:
[code]...
How do I initialize both instance and shared members without re-initializing the shared members every time an object is created from a class? Thanks!
I've been trying implement Constructor method in passing variable between two forms.Just a rough user interface guide - issue Invoice. User would type in all the Customer Name, Document Number. Once he reached Item Details, a Child Form would pop-up for the User to select/search the Invoice's Item; Once selected, the selected item would showed in the primary Form.
What I had tried is, the Constructor method worked perfectly when it is self-contain in a new project, yet to be implement in my application.But when I implemented, there is an error: Reference to a non-shared member requires an object reference.
[Code]...
I would love to use the following procedure to set the Title, keywords etc. of my pages, in a module.
Public Shared Sub SetTitle(ByVal Heading As String, ByVal Keywords As String())
Dim myMaster As Masterpage = DirectCast(Me.Master, Masterpage)
If Request.QueryString("lng") = "es" Then
[Code]....
The problem is that i get two errors.
At Me.Master i get the 'Me' is valid only within an instance method. error and at
If Request... i get the 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.
So how do i fix these? I would like to have that procedure in a common place and not in every page.
I have a form (frmMain) that contains a custom control (con class). frmMain contains a combo box control and when the user selects a value from it, I pass this value to a sub routine within con class (see red line below). This purpose of the sub routine is to populate a set of comboxes contained in con class according to the value that is passed in.
Private Sub cboGuidelines_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboGuidelines.SelectedIndexChanged
If bChanged = True Then
[code].....
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?
I 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.
I have the following class in a .NET class library:
Code:
Public Class JasonTest
Sub New()
End Sub
[Code]....
The .AddNumbers call works fine, but the AddStrings call yields the error 'Object doesn't support this property or method'.
Is there any way to call a shared method from .NET in VB6? I was unable to find any documentation on this.
I'm not sure if I'm going mad, it's always a possibility. But is it possible to call a shared member of a class given its 'System.Type' object?
View 4 RepliesAs 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.
View 3 RepliesI 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?
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.
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
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.
View 1 RepliesI 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
How can i use Server.MapPath in shared methos i tried something lile this [code]...
View 1 RepliesIf I have two threads both calling a normal function at the same that appends strings, sometime the output string is a combination from both threads as the function had not finished executing the code before it was called again... Would a shared function wait to finish first?
View 9 RepliesI 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.
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?
View 3 Replies[code]...
Dim ass as Assembly = Assembly.LoadFile("sample.dll")
Now, I want to call the shared method using the class name.
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]....
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).
Can we override a Public Shared method in derived class? If not why?
View 2 Replies(I tried with this question but this code isolates the problem better. I have this code:
Public Shared Sub PopulateTextFields(ByRef stuffList As List(Of Stuff))
Dim aStuff As New Stuff
For Each aStuff In stuffList
DoStuff(aStuff)
Next
End Sub
[Code]...
Inside 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.
Will 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]...
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.
