.net - Don't Create Local Variable To Hold The Reference Of The Object?
Nov 17, 2010
How does the GC dispose objects created in the following 2 scenarios?
1)
Private Function DoSomething() As Boolean
Return New DatabaseManager().Insert()
End Function
2)
Private Function DoSomething() As Boolean
Dim mngr As New DatabaseManager()
Return mngr.Insert()
End Function
In Option 1, I don't create local variable to hold the reference of the object. In Option 2, I hold the reference in local variable.What option is better and why? (if any)
Function GetSomething() as String GetSomething = "Here's your string" End Function or Function GetSomething() as String Dim returnString as String = "Here's your string" Return returnString End Function
Obviously, neither of these implementations make any sense, but they're just meant to illustrate my point. Is there anything to be gained by using GetSomething itself to store the return value instead of declaring returnString locally and then returning that (does it avoid having an extra string allocated/instantiated - and if so, are there any performance/memory benefits)?
is this safe (I know it works, but is it safe)? Is it returning a reference to a local variable, wich falls out of scope as soon as the function returns?
Public Function myfunc() As String Dim strXml As String
I pass this class i created a variable by reference and i want that reference to be assigned to m_Text so that when i change m_Text it changes the TextValue variable i passed. Example:
Dim test2 as String = "ok" Dim test as New GeneTextBox(test2)
'then some one changes the text in the GeneTextBox and i want it to change the test2 string...
Public Class GeneTextBox Inherits Windows.Forms.TextBox Private m_Text As String Public Sub New(ByRef TextValue As String)
The code below works for the class that I hard coded "XCCustomers" in my RetrieveIDandName method where I use CType. However, I would like to be able to pass in various classes and property names to get the integer and string LIST returned. For example, in my code below, I would like to also pass in "XCEmployees" to my RetrieveIDandName method. I feel so close... I was hoping someone knew how to use CType where I can pass in the class name as a string variable.
Note, all the other examples I have seen and tried fail because we are using Option Strict On which disallows late binding. That is why I need to use CType.I also studied the "Activator.CreateInstance" code examples to try to get the class reference instance by string name but I was unable to get CType to work with that.When I use obj.GetType.Name or obj.GetType.FullName in place of the "XCCustomers" in CType(obj, XCCustomers)(i)I get the error "Type 'obj.GetType.Name' is not defined" or "Type 'obj.GetType.FullName' is not defined"
I was create Access database with Access 2003. I create VB project with Visual Studio 2005 Standard With connection wizzard I create coonect with this Access database, select all tablesI see this database inside Data sources and inside Server explorer Test connection is OK When I drag and drop table from Data sources, Wizzard don't create DataGridView, DataSourceBinding etc .. and I see popup window with mesage: Object reference not set to an instance of an object and then "game over"
Im trying to build an error-logger that loggs running values that is active in the function that caused the error. (just for fun so its not a critical problem)When going in break-mode and looking at the locals-tab and autos-tab you can see all active variables (name, type and value), it would be useful to get hold of that for logging purposes when an error occur and on some other occasions.For my example, I just want to find all local variables that are of type string and integer and store the name and value of them.
I am attempting to create a new mobile app using VB in visual studio 2008. I select "File" "New Project". Select "Smart Device" in new project window. Select the "Smart Device Project" from templates. Select ".NET Framework 3.5". Select "OK" and get the dreaded "object reference not set to an instance of an object"
how I can reference a report variable in the Report Properties Code Window of a local report? I have tried Variables!Claimant.Value (for a variable called Claimant) but I get an error "Reference to a non-shared member requires an object reference." I have tried qualifying it with Report. and also with the report name in front of it but I get errors with this also.I have the variable CLaimant defined in the Variables section of the Report Properties.
String s = "test"; String is a class, so to use it we should create an object of it. But rather we just make a reference of it and give it a value. How is it possible and what concepts are used in it. The metadata of String class shows the following :
Is it okay for a structure variable to hold a small number of reference types? I thinks it's fine because the pointers themselves are not that big, regardless of what they're pointing to. But I never did fully figure out the whole heap/stack thing, so I'd like to make sure.
I am trying to create new variables inside a class after creating its object at runtime. The problem is that I don't know the variable names or the value beforehand so I have to create the new variables at runtime.
[Code]...
This is a more elaborate explanation of my code. If you observe that in the Eval function I have tried to evaluate Fval(abc). Now the object array abc is not declared in the Test class because it existence is not known beforehand. What I want to do is create an object array abc of length 2 and populate it with some values and when Fval(abc) is called then then the value of index 1 should be the return value of Eval fucntion.
How do i make a variable that can hold more than 1 piece of data. I wan't a variable that can keep 4 number in it. When i count them in using a for loop the only thing i have after it is finished is the last number counted in by the for loop.
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
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]
