Shallow Vs Deep Copies Of Objects
Oct 19, 2010
Shallow vs. Deep copies of objects. Why would anyone want a shallow copy of, say, a multidimensional array?! If I wanted something to act just like something else (and this is what shallow copies do), why would I create a second instance to do what the 1st instance does already? I think I understand the point of objects and that just copying the contents of one object to another does not make them independent, but it seems that the whole point of doing:
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Dec 1, 2010
As I understand it a shallow copy is like a CLONE copy of an object where the values for each property are independent of one another whereas a DEEP copy is a copy that uses the same memory locations and therefore if you change a value in one it is also shown in the second item ( By Reference to the same memory locations ).So my main question is, when dealing with CLASSEs, STRUCTUREs etcetera containing REFERENCE types.is there anyway to quickly create a CLONE or shallow copy of an OBJECT or not ? The only way I can think of is to put the item into a one dimensional array and use the CLONE method for an array. [code]
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Jan 31, 2010
Is there any way possible to deep copy a Control? Just want to know if its possible
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Sep 23, 2009
I am after some GDI+ help, Basically I have an LED display which for example is 300 LEDs wide by 300 LED's deep, so you could say it has a resolution of 300x300.I am intending to use windows to process images ready to be sent to the display (as the display is dumb and simply displays what it is sent, But I require that the images are animated as well as static sort of like the basic PowerPoint animations (scroll on/off etc).to achieve this I need to write some code that creates frames much like gif's. So to scroll a 300x300 image onto the display I would need 300 separate frames.
So I have written the following code that uses the GDI+ objects to build the frames needed to scroll an image from the right or left.
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Jan 12, 2010
I'm looking for a recursive subroutine.I have the dataset from sql-server with in the datasource-table a parent- and a child-column.
I made a routine to put the parent-nodes in the tree.The problem starts with the childs over so many levels.I can write it out but it is to much code, I'm sure it can be done more efficient with a recursive subroutine.
.tv_Ana.Nodes(A).Nodes(B).Nodes(C).Nodes(D).Nodes(E).Nodes(F).Nodes(G).Nodes(H).Nodes.Add(Trim(sLev_nI + "-" + row_nI("MidCod").ToString()))
The tree will be about 25 levels deep.A few days ago I saw a recursive subroutine to fill the childnodes without the above difficulty to write alle the levels in code.That example I cannot find it any more, but it had a line of code more or less like this here below:
Dim
Nodes As TreeNodeCollection = tv.Nodes(A).Nodes
but it doesn't work yet!
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Jan 20, 2010
I have created a form with a tab control that I want to be able to make a copy of in such a way that all the child controls and their data are copied as well. I have tried this:
Dim NewPage as TabPage = tcViews.TabPages.Item(0)
tcViews.TabPages.Add(NewPage)
I end up with a reference to the first page. That is, if I change something in the old page, it changes in the new one as well. I believe this is because VB.NET treats assignments of classes as references, rather than values. Hence only the memory address of the original is copied, so essentially both refer to the same tab page in memory. I also tried serialization and deserialization.
The TabPage is apparently not serializable. And I heard about MemberwiseClone, but it isn't accessible, according to Visual Studio. There doesn't appear to be a Clone method available either. How do I make a new tab page that is totally independent of the original, but that has copies of the original page's controls and their property data, which can then be edited independently of the originals?
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Aug 15, 2006
If I have a generic.list(of ClassA), is there a simple way to create a deep copy of this list that will not affect the original copy? It seems to work if I have a generic list of Structures, but for some reason the copy constructor for lists of classes only copies pointers to the elements (or maybe a pointer to the whole list?). I would move to structures if it were not for the fact that I can't find a way to edit the members in the structs in the list. eg:list(0).a = 5 'Does not workIs there some way to get around this without declaring an instance of that structure, like this:dim str as StructA = list(0)str.a = 5I'd
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Aug 5, 2011
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?
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Mar 13, 2010
I have a button ad a list box, the button when clicked lets the user select a directory on the HDD, and then the app is meant to list all the sub directory's of that folder int he list box. However I cant seem to get it to list just the sub directory names, not the full paths, and also to only scan by 1 folder deep (selected foldersub folder).
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Oct 27, 2010
Following up on my question yesterday to deepcopy an object with events in C# and attach the events of the original object to the Cloned copy is pretty easy, you just set the Event declaration in the Copy = the value in the original. Deep Clone when events are attached. How do you do this in VB.Net? (Using .Net 2). Maybe there was something with reflection where you can examine what events are bound and somehow transfer those to the new object.
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Feb 6, 2012
I am trying to make a deep copy by adding a clone property to my class.
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Apr 27, 2009
Essentially what I want to do is copy a WebBrowser object such that I can do the equivalent of "Open In New Tab" or "Open In New Window" actions, maintaining any posted data. I don't just want to navigate to the same URL as in the original WebBrowser object, rather I want to repeat the HttpWebRequest.
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Apr 18, 2012
I have an object (a third component gridview) which is serializable, and I need a deep clone of this object. I have the following code which throws the exception."The type System.Windows.Forms.Control in assembly System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKey Token=b77a5c5 61934e089 is not serializable".So the gridview's base class is System.Windows.Forms.Control, which is not serializable. How can I get a deep clone from the gridview? [code]
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Nov 22, 2011
I would like to get the number of copies of a job, in the que and limit the users if they print more than selected copies the the queue should pause it. not the number of pages in a job, the number of copies, and the second thing is , this code works on the local machine, how if a print is sent from the network, is there any way that I can pause that print wich is coming from the network or another machine, on the network, most of my printers are connected through ip, and some are shared printers.
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Jan 9, 2011
An interesting feature, I have seen in jDownloader software is any links I copy in the browser window (i.e., Ctrl+c), the copied content links automatically appears ( i.e., with out me actually pasting it) in their UI and starts downloading the content from the links, if they are valid.I would like to program the same but am puzzled as how to access the variable to which OS copies.
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Aug 26, 2010
I'm looking for a way to have my code build two copies of itself at once.The program has an "A" and a "B" configuration that need to be compiled as Prog-A.exe and Prog-B.exe every time the code is compiled. I can do this manually, but I assume there's some way to do it in code? What I'd like is to use conditional compilation to have the A configuration compile so that it runs a "setup as A"-type method on load, and the B likewise, and then have it compile both versions each time.
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Jul 14, 2011
What I mean is, I would like to make an exclusive program, but I don't want it falling into the hands of someone I didn't give permission to.Or perhaps make it require a password to function, and be able to change that password for all copies whenever I want.
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Aug 29, 2009
I am working with VB2008 sp1 and I want to use some of the Windows API calls. I need a copy of header files so that I can set certain constants to their correct values. Do I have to install sdk 6.1 and will this damage the sdk 6.0A that is already installed. I only use VB and I do not have any other language such as C+ or C# installed
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Apr 2, 2009
i want to write a program to get nuimber of pages printed from a specific printer. i spent a lot of time for googling and i finally managed to get acode that is posted in this link given below [URl]..the problem with above code is its getting no. of pages printed but not getting no. of copies printed for eg: if no. of pages to print is 2 and no. of copies is 3 the total no. of pages printed will be 6. but im gettin total pages printed is 2 ie no. of copies is not getting
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Nov 15, 2010
I already have barcode created for each stock. And when user click on the print button, it will prompt user how many copies to be printed out.How to do the print out of barcode?
Question Two How to code something to check how many copies of the current barcode size can fit in A4 paper?
I want to fully utilise an A4 paper size before a new A4 paper is used.
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Oct 9, 2011
I've a Crystal Report of one page. Only one.
I want to clone that page, so when you print that report, you get 2 copies with the same data.
I know can be done manually, but i want to avoid of setting up the printer and write "Yes!, i want 2 copies of this".
Timelines ->
NOW ->
Use software, generate Crystal, go to in-built crystal viewer print button, write '2' in copies, print.
I WANT ->
Use softwre, generate Crystal, print dialog come up (this is done), you hit 'Enter' and 2 copies will be printed (a.k.a 2 pages which are the sames)
I looked up for sub.reports but i don't want them in the same page.
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May 3, 2012
I have what I think is impossible to achieve. I am printing labels to a zebra printer. Each label is to be attached to an individual item in a batch. The client wants a separate serial number on each label.
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Dec 5, 2011
make objects from the ToolBox using code instead of changing existing objects invisible then visible later?
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Jun 23, 2012
I am getting this error, Not sure why it is happening "Error The SqlParameterCollection only accepts non-null SqlParameter type objects, not Int32 objects."I have tried with all sorts of possibilties, now try to enter default data as dummy data,
Using connection As New SqlConnection
connection.ConnectionString = ConfigurationManager.ConnectionStrings("DentalDeviceConnectionString").ConnectionString
connection.Open()[code].....
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Jan 29, 2011
I have a program like this.
Module Module1
Public Class Mstr
Public Property Prop1 As String
Public Property Prop2 As String[code]....
But it is not working as I expect it to. You can see it from.The DtlsB properties of all three DtlsA objects are having values from last iteration.
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Jan 6, 2011
I want to let the user input objects to a richtextbox 1 object on each line, and somehow use Random.Next to select pseudorandomly a few objects, the number 'few' inputted in a textbox.
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Jan 18, 2012
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Using conn As New SqlConnection("Database=Clinic_Management_System;Data Source=.SQLExpress;Integrated Security=True;AttachDBFilename=|DataDirectory|Clinic Management System.mdf")
Dim cmdRecord As SqlCommand
[code]....
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Feb 7, 2010
I have a user control that inherits the FW ListView and I need to dispose of two objects when the form's disposing of it's objects. Here's what I've concluded already, am I on the right track?
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Sep 7, 2010
In VB .NET, how can I have two copies of an executable communicate with each other over the internet? For example... similar to how and instant messenger might work.
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Jun 21, 2010
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i have 2 listviews in which folder and files are loaded. i'm trying to make a function that, when "Copy" button is pressed copies files/ folders between listviews (between folders "ex: from "D:path" to "E:pathsubpath"). the codes of file copy and folder copy both work but not if add the file.exists / folder.exists lines. if i put a msgbox instead of the filecopy/ foldercopy it displays "file exists" or "folder exist" etc. .. but if add the file copy / folder copy line doens't do nothing.
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