This should be a fairly common question, but I haven't found a straightforward answer anywhere.
If I instantiate an object within a function in VB.NET and return it, does it return it be reference or by value. IE - should I be worried about performance if I write something like this:
Public Function ret_obj_func() As big_object
Dim ret_obj As New big_obj(<lots of stuff>)
Return ret_obj
End Function
If I call this function from somewhere else, will it instantiate the object in the ret_obj and then create a deep copy to pass back a copy to the caller, Or will it just pass back a reference?
If I instantiate an object within a function in VB.NET and return it, does it return it be reference or by value. IE - should I be worried about performance if I write something like this:
Public Function ret_obj_func() As big_object Dim ret_obj As New big_obj(<lots of stuff>) Return ret_obj End Function
If I call this function from somewhere else, will it instantiate the object in the ret_obj and then create a deep copy to pass back a copy to the caller, Or will it just pass back a reference?
I am working on a application that has quite a few functions involved and have been thinking of the following: If I have a function that has a few paramaters, is it more efficient to pass the objects to the function(Example 1) or reference the objects in the parent(Example 2)? Does it matter if the objects are large or not?
Example:
Class mainform Public myGenericList As New List(Of String) Public myDatarowArray() As DataRow
I call the function GetDataTable and when it gets to the return line, I get the error message: Object reference not set to an instance of an object.
Dim DB As New DBConn Dim gd As New DataAccess.GetData Dim DT As New DataTable
[Code].....
Updated. I'll see if I can update with the DataAccess.GetData code. I didn't originally put it in there because our shop use it all the time and have no issues with it.
Public Function Gen2Read(ByVal hComHandle As IntPtr, ByVal Membank As Byte, ByVal WordPtr As Byte, ByVal WordCnt As Byte, ByRef value As IntPtr, ByVal ReaderAddr As Byte) As Integer End Function
I'm trying to re-write an old VB 6 OCX into a VB.net DLL and I'm having problems accessing the object returned from a COM object. Here is a snippet of the old VB 6 code: Dim objResult as Object
When I query a DataTable using LINQ, are the rows returned as references? Either way, is it possible to control this behaviour, so that rows are either returned as references or as new rows?My guess is that all objects are returned as references by default, since that seems to be the normal behaviour in most programming languages.
The book "Beginning ASP .NET 4 in VB 2010" contains the following:NOTE: TaxableProduct inherits from Product.You can also cast in the reverse directionfor example, cast a Productreference to a TaxableProduct reference. The trick here is that this
Private Sub SpellChkMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles SpellChkMenuItem.Click Dim activeRichTextBox = TryCast(Me.ActiveControl, RichTextBox) 'clsFS.CheckSpelling(activeRichTextBox)[code]....
When I am in the rtb and click on spell check button it tells me the error "Object reference not set to an instance of an object." On this line
SpellChecker.Text = activeRichTextBox.Text
But it is suppose to be getting the focused rtb correct? So why is it not referenced
How to give another function's returned value in LINQ.[code]but in above query I should write code to store the return value of GetObjProperty Value(p) and add obj-p and returnValue combination to the dictionary.The last line below code is wrong. but please suggest me how to correct it. My intention is, I want output collection(say dictionary) of each fruitname and its color(returned by other function call) for all the fruits which the GetFruitColor is not nothing(it can be empty or valid string).[code]In above code last line is wrong. So how to put getFruitColor in k, how to correct it to save the k value and give me output as dictionary of fruit and k value.
Why this code doesn't work? It returns an unexpected value actually total = 0. total = Cscore(TextBox1.Text) * CDbl(TextBox2.Text)
When trying this total = TextBox1.Text * TextBox2.Text It returns the expected value but I need to pass textbox1.text to the function to get the desirable value
The function is this Public Function Cscore(ByVal score As Integer) As Double Select Case score Case score = 100 Return 5.0 Case score >= 95 [Code] .....
I'm new to VB.NET and want to parameterise the SQL Connection Strings in my VB.NET App. I've added a function to my Main Form to retrieve the App.config File like:
Imports System.Configuration Imports System.Configuration.ConfigurationSettings Public Class MainMenu [code]....
In my other forms when i want to reference the Connection String, i get an error saying getConnStr is not declared?
Private Sub UpdDept_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Try myconnection = New SqlConnection(getConnStr()) <============= Dim mycommand As New SqlCommand()
why i get this when i've declared the Function as Public?
When the AlertsSettings.xml is not present the Appsettings is assigned to nothing. The variables that follow that definition rely on the existance of that information which will normally be set by the load method. But when there is a problem and either of the variables do not get a value how do I handle that in the code that relies on those values. The Settings class deserializes an xml document and assigned values to properties.
Sub Main() Dim Appsettings As Settings = Settings.Load("AlertsSettings.xml") Dim AlertsServer As String
I 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:
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
I 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)
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
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]
Alright, 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.
im 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
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
I am getting the following error when I call another form from Form1 and fill out the text boxes and Press Ok button. For some reason I cannot access the datatable (dt) from Form1. It gives me the following error: Reference to a non-shared member requires an object reference
