I'm doing some reading up on the differences between Value types and Reference types - is there any quick/easy way of telling whether a type is Value or Reference? I couldnt see anything in Intellisense so had a look at MSDN pages for a few classes [URL]but it doesnt seem to mention it there either.
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In VB.NET, if I create a class it is a reference-type. But, if that class it chock full of value type properties, how is this handled? If the class is instantied but never filled, I suspect a pointed for to the heap is allocated. But is more space allocated on the stack for all of it's value type properties?
View 4 RepliesIn .NET, integer data type is a value type(stack) and String is a reference type(heap). So If a class A has an integer, and a string type object in it, and a class B creates an object of class A, then how will this object of class A be stored in memory? In stack, or in a heap? This was asked in my Microsoft interview. Need to understand how I fared.
View 3 RepliesI've come from a Assembler and C/C++ background, so I understand the concept behind reference types versus value types in vb.net. Also, I've read Jon Skeet's article regarding references and value types and I understand all of that. My question is: How can you tell if a given type is a reference type or a value type? Is it simply that all integral types (ints, floats, etc.) are value types and all classes are reference types? (If so, where do strings fall?)
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I also.But problem is I generally mug up things for identifying that it is value type or reference type Like class is reference type and structure is value type .. I made a list and paste in my mind .. But of course it is wrong. how to differenciate between value type and reference type by its behaviour or looking at its properties or run time behaviour etc .So that I need not to remember the list..
View 4 RepliesI've got a class, lets call it Person, which needs to keep some data (in the form of another class which we will call PersonData) in one of its properties - the problem is that I will have several instances of this person class and they all need their own 'copy' of the data (just in memory, its not a file or anything).Hhow would I do this? At the moment because everything involved is a Reference type, I'm assuming that if I were to create 2 instances of my Person classes and assign the same instance of the PersonData class to their properties then when one Person class made a change to the PersonData it would be reflected in the other Person class right? How can I avoid that and make it so that they both have their own version of the data, without having to repeat the procedure that fetches the data in the first place?
I'll explain my exact situation just in case it helps, but this is more of a general question as I could probably get around it in this case by copying the byte array I receive from the server (hopefully that will make sense once you read the explanation below) :
In this case the data I am talking about copying is actually received from a server via TcpClient. The thing is, when the client requests the data from the server over the network, the server has to go off and query several other servers etc so I do not want to be requesting data from the server every single time as that would be a big waste of resources and time. So when a request is made and data is received back from the server, several of these Person class instances will be created (in reality, its a few different classes but that doesnt make a difference for this example) and each need to have access to the full data that the server has sent back but in some cases the Person instances might need to modify the data and this is where the problem appears as they will all be working on the same data.
When I try this, I get the compiler error below:Return TryCast(obj, Double?)'TryCast' operand must be reference type, but 'Double?' is a value type.
This confuses me, I thought that when you make a value type nullable, boxing will be applied - which results in a reference type?
I have a mutable class that I'm using as a key to a generic dictionary. Two keys should be equal only if their references are equal. From what I've read, in this case, I don't need to override Equals, GetHashCode , or implement IEqualityComparer.
View 5 RepliesAs the reference values are stored in the heap as a data; where do the type information of any reference value is stored?If there are a couple of instances of class Artist; when they are stored in the heap how the .Net tags those memory blocks as type of Artist?
View 3 RepliesI m working on one of vb6 projects. There are total 3 projects. One of them is ActiveX Exe is and has main method, second one is also AxtiveX Exe but doesnt have main method (only Classes) and third project is of ActiveX Dll.Well I m trying debug and issue and trying to put all 3 prjts in 1 Group prject but some how I cant add reference of 2nd prject into the first one. I get an error of " cannot be referenced because its project type is exe" but I can add a ref of its compiled exe but this doesnt help in debugging of whole prjt.
View 7 RepliesI'm trying to create a generic function to build a Linq expression from a list of Telerik grid filters. I'm trying to stay clear of dynamic Linq. Because I don't know the type that I'm building the expression for, I'm attempting to use reflection in the lambda functions to refer to a property, but after applying the fix suggested by @JaredPar I get the error, "The LINQ expression node type 'Invoke' is not supported in LINQ to Entities." Is there any way around this? here is my code:
Public Shared Function buildRadFilter(Of T)(ByVal filterExpression As List(Of GridFilterExpression)) As Expressions.Expression(Of Func(Of T, Boolean))
Dim returnPred = PredicateBuilder.True(Of T)()
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I have searched for two weeks, every night, exhaustively reading forum threads and trying all suggested solutions no matter how outlandish. Just as is the case with the many many forum threads about this same issue, the site works fine on my development machine. It deploys with no errors. It works from the production server and reads data from the database, but when it attempts to access a profile it crashes with this error.
A number of posts say to check or uncheck an option called "remove app_code.compiled file" but apparently this was a Visual Studio 2005 option. It is nowhere to be found in Visual Studio 2010. A number of posts say to make sure the App_Code.dll is present in my bin directory. It is present. I've deleted the app_code.compile file manually to see if that made any difference. I've changed the target framework from 4.0 to 2.0 and 3.5. I've completely deleted the site in IIS, created a different folder with a different name and redeployed the site with every combination of "allow this precompiled site to be updatable" and "Use fixed naming and single page assemblies".
i've included references to System.Web.Profile and System.Web and System.Web.Profile.ProfileCommon. I've created a new, fresh website targeting .net framework v4.0 and copied that web.config file to my application and recreated my profile entries to ensure that I didn't jack anything up in the config file along the way.
I have a big problem.I'm starting with Visual Basic (2008) and I get this error when you want to run the program,
Warning 2.Unable to load the type library for reference "MSCommLib.Library not registered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED)) prjRxData
I have an issue with a third-party COM+ DLL meant to be used from VB6, where it has a function to set a Callback for a hardware event. However, I'm using VB.NET, and AddressOf now returns a reference type instead of an integral type, which means that the setCallback function on the COM+ DLL apparently can't be used.
View 1 RepliesI'm using Visual Basic 2008 Express in Windows XP Home edition. I'm trying to compat a MSAccess database using code. When the program is loaded, the error window shows the following comment: Cannot load type library for reference "ADODB". Library not registered. (Exception from HRESULT: 0x8002891/D (TYPE_E_LIBNOTREGISTERED))
Checked some forum sites and they suggested that some .dll files were corrpurted. I went back to Microsoft and resintalled the Visual Basic 2008 Express package from the Web Site.
When I tried to start my visaul basic program, the error was still in the error list.
I've got an XML file with the following sample structure:How can I get the value of the element <Reference> where the <Organisation Type="Seller"> and the attributes are AssignedBy="B" and Type="T1"
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Or change 'Select a' to 'Select a.value', but is not giving me the result
I have 2 projects, one built in VB.NET and another in C#.NET. I want to use certain functionality of VB.NET into C#.NET and hence I have added the dll file of VB.NET solution into C#.NET as a reference by browsing the dll from my system. Say dll name for VB.NET is myData.dll. In my C#.NET project I am trying to declare it as a namespace i.e. "using myData;" and its giving me an error of "Type or namespace name could not be found"
View 1 RepliesI am receiving this error: Reference to a non-shared member requires an object reference on the code I've
bolded within the code body. Here is my code:
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I get this error:Reference to a non-shared member requires an object reference.When i compile on the following code section:
Private Sub statusBarToolStripMenuItem_Click(ByVal sender As Object, ByVal e As EventArgs)
ToolStripMenuItem.Checked = Not ToolStripMenuItem.Checked
statusStrip1.Visible = ToolStripMenuItem.Checked
when I do something like this: Process.Start [URL] it says that error only on Form2 not Form1.
View 2 RepliesError 'Reference to a non-shared member requires an object reference'?I want to know what a non-shared member is.
View 2 RepliesI am opening frmB (variable for FormB - the actual form) from frmA. From btn1 I open frmB like this:
frmB = New FormB()
frmB.Show()
From btn2 (frmB is already open) I bring frmB to the front from behind frmA:
FormB.Show()
FormB.BringToFront().
No problem so far. Now I need to pass an arg to frmB. This is where I am having the problem.
from btn1 (in frmA) I do this:
frmB = New FormB(myArg) '--pass myArg to constructor of FormB -- no problem here
frmB.Show()
then from btn2 -- this is where I have the problem
FormB.Show()
FormB.BringToFront()
I tried placing myArg in FormB.Show(myArg) but that did not fix the problem. What is the correct way to pass myArg to FormB (frmB) in this scenario? Do I need to share FormB or frmB? How do I do this? "frmB" is frmA level variable.
why i am getting an "reference to a non-shared member requires an object reference" error on format.Yesterday gets the previous days date and presents it in a yyyyMMdd format.vsettlementDates takes the "Yesterday value and requests data from it.
Dim Yesterday As String = format(Today.AddDays(-1), "yyyyMMdd")
Dim vSettlementDates As String = (Yesterday)
I am getting the following error:
Error 1 Reference to a non-shared member requires an object reference. (on WindowsIdentity.Groups)
Here's my code from that uses the WindowsIdentity.Groups property to display the identity references for the groups the current user belongs to. This code is part of a larger example provided for the WindowsIdentity class.
Public ReadOnly Property Groups As IdentityReferenceCollection
Get
Dim irc As IdentityReferenceCollection
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" GridView1.datasource = _MyUsers.Reference to a non-shared member requires an object reference." error. WHat's wrong with this code
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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I have the following code below, how the line where it says : For Each c As councillor In councillorList i get the error: reference to a non shared member requires an object reference. Can someone please advise where i am going wrong? [Code]
View 2 RepliesAlright, so im getting this error:Reference to a non-shared member requires an object reference.This is the bit of code the error is pointing to:My.Settings.Bookmarks.Add(WebBrowser.Url.ToString)Why is it giving me this error?Its saying WebBrowser.Url is the problem.
View 1 Repliesim sure it is something really simple. Im by no means comfortable with VB. The below code is not mine but i have altered it for my needs. However im getting a couple of errors.
Reference to a non-shared member requires an object reference. I have underlined the errors in the code and they all refer to the above description
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Im trying to create a login page which accesses a mysql database I keep getting this error: reference to a non shared member requires an object reference
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Can I reference a dll programatically in VB.net? Or change the Local Copy path for a dll reference?
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