Copy A List To Store Original Values To Be Used Later?
May 24, 2012
I have a WPF form that takes a list of objects that have locations and sizes and plots them on the canvas. I'm currently trying to implement an undo button that will throw out all the changes that have been made to the positions of the objects and revert back to the original collection that was retrieved when the form loaded.
As it stands now I go out to the database on the load of the form and get all the objects that will need to be displayed then assign the list that is returned to two seperate collections. The problem that comes up is that the two collections are actually pointers to the original collection and whenever one is changed the changes are reflected in the second collection.
Is it possible to copy a list of objects so that changes made to one collection won't affect the secondary collection?
So far I've tried simply using the assignment operator, passing the source collection into a function byval and scrolling through each element of the list manually adding it to the second collection and using linq to get all the objects from the original list and pushing the results to a separate temporary list and assigning the second collection to the temporary list.
I feel like I'm overcomplicating the issue but almost all the places I've come across while googling say that this behavior is by design, which I understand but it seems like this would be a fairly common idea.
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Jun 19, 2011
I have an array of people stored in a custom structure array... how can i copy this array to a temp array so that the temp array has all the same values as the original custom array?
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Nov 28, 2010
I made a copy of a VB application project, to make a copy of it for testing.
But when I debug the test copy while the orginal is still running (debugging from Visual Studio), focus changes to the original's main form, and the test copy does not run.
If I try to single step the test copy, same thing, focus changes to original, and test copy does not even step.
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Jul 11, 2009
I have a current program that I have developed using visual basic and it does everything I want, however, I would like to "experiment" with the code and add other things to it but I don't want to mess up the code by working on my original project. How do I copy the project so I have it safe and have one I can "play" with.
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Dec 8, 2009
I am using Visual Studio Professional 2008. I am writing a program in Visual Basic 2008 that copies the Used Range from one worksheet to another worksheet, I am able to achieve this by the following code segment:
[Code]...
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Aug 16, 2010
I am using VB 2008 and Access DataBase. My code need to store original data values for row being updated to compare it with new values later. For this to accomplish I wrote following
Dim dRowOriginalRow
As DSetPurchaseSale.PurchasesRow
Private
Sub btnEdit_Click(ByVal
sender As System.Object,
[Code] .....
When I am running this code, i am not getting the original values in dRowOriginalRow variable insted it is also updating with new changes made in controls, so the dRowOriginalRow and dRowModifiedRow are always same. Again may I use Equal To sigh to compare both rows as I did in my code?
True : dtPurchaseDate.Focus()
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Oct 24, 2010
If I use a LINQ query over some type of collection, is there any way to know the initial index of an element of the result?
Purpose: I make a query to set as source of a DataGridView, and on a (button)cellclick event I want to a call a method that needs to reference the collection at the correct index.
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Jun 21, 2010
I was wondering how you can copy information (from a webpage, for example) and store it in a string?Also, how would I take only one word of the string if there are spaces between words and I will always be removing the word with the same location in the string (for example, the last word in string).
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Jul 27, 2010
Is it possible to code to copy store procedures from one SQL server to another SQL server in vb.net application without using SQL server replication?
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Oct 26, 2011
This is probably a really basic question - but I have a list of items (custom objects) being passed from one winform (.net 3.5) to another. I want to create a local list to store changes that only get persisted if the user clicks save. Currently if the user clicks cancel - the changes are still applied in the first form because I assume the objects are reference type.I have the save working as it calls a service layer to do the save and then refreshes the other form - but not the cancel.
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Apr 18, 2011
I'm using System.Management.ManagementScope to connect to a remote computer and install an MSI package. This works great if the MSI is located on the remote computer, but it fails if I try to use a network location to run the MSI from. The UNC path is correct because if I manually type it from the remote computer it runs fine. There must be a limitation (security I'm thinking) that prevents things from running via WMI if the exe isn't local to the remote machine.My last hope will be to copy the MSI from the network location, store it locally on the remote computer, then run it - but I'd really rather not have to do that.
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Jan 9, 2012
I am trying to store 5 values and an associated unique key. I need to search for this key and update the 5 associated values. I'm guessing I would use an object as the value but how do I get the values out from the object?
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Mar 25, 2010
I am trying to create a "Generate Number" application. It needs to generate numbers ( 1 - 100 ) and add them to the array. I have the numbers generated already and outputed into a list box. but I am not sure on how to add them to the array.
I have generated the numbers using for...next and do while loops. But I haven't been able to get the right syntax to be able to add the numbers into the array. [code]/...
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Apr 22, 2010
I don't know if I can have several same forms to do the manager jobs, ACTUALLY THE STORE VALUES ARE DIFFERENT(those forms can have the independant data values to store into the forms), like if I can have the datagridviews to store the different values? SO,MY QUESTION IS if I can have several same forms(FROM ONE SAME FORM), and can store different data values into the forms with vb.net & access, OR I HAVE TO CREATE SEVERAL SAME FORMS.
[Code]...
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Jul 5, 2009
I have the following code which obtains the compass direction from a degree value. I'm new to VB.Net and was wondering what is the best way to store the values, in an Enum or an Array?
[Code]...
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Mar 29, 2009
I'm trying to convert old code to VB in VS2005. The code I'm working on is used to store values in a string, which will then be handed to a proprietary scramble function. This function is a given in this case. I've already switched from a string to an array of bytes in my .NET code.
The old code (VBA) was using a string value to store the data, example function for Double value:
Private Function DoubleToStr(ByVal value As Double) As String
Dim Bytes(7) As Byte ' 0-7 Double is 8 bytes
Dim n As Long
CopyMemory(Bytes(0), value, 8)
DoubleToStr = ""
For n = 0 To UBound(Bytes)
DoubleToStr = DoubleToStr & Chr(Bytes(n))
Next n
End Function
The code basically copies the memory contents (using API call CopyMemory) of the memory (held by the double variable) to the memory held by a byte array. It then reads the byte array and converts it into a string. Workarounds could be to convert a bool or long to a string, though that would be expensive in terms of memory/storage eg. 1234564787 would be 10 bytes in a string where as a long is only 4 bytes (factor 2.5 increase).
How to retain the original precision? Converting it to a string would result in endless numbers. Another problem (at least I think it could be) is that in VBA the variables are rather simple, but in .NET they are all objects, so how to retrieve the actual memory location of the value? let alone garbage collection moving stuff around. How to get those variables stored in my byte array?
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Jul 19, 2011
Here is my select stament to store values when username and password and check boxes are check
com =
New OleDbCommand("INSERT
INTO Users (UserName,Password,IsAdmin,Read,Write,Change,REMOVE,User_st) VALUES ('" & txtusername.Text &
"','" & txtpassword.Text &
"'," &
CInt(chkIsadmin.Checked) &
[Code]...
My problem is this wehen i add new record to my db it saves values like this the value of read column is as follows read = 1 when check box is checked and read = 0 when check box is checked but i want to save true or false instead 1 and 0 how to achieve this using vb.net and my db is Oracle.
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Apr 24, 2009
I built a small website and there will be only one admin, so in the admin panel I am asking for a password with a value that I do not retrieve from a database, I just hard coded it in the function in code behind, I know this is wrong though I don't know why.
So is hard coding it in web.config the right thing to do? and how?
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Mar 8, 2011
I am attempting to teach myself visual basic and I cannot figure out how to send a calculated value (on a button click) into a one-dimension array and then recall the last five values in a message box when the user exits.
Here's what I have:
Public Class frmInvoiceTotal
Dim totals(4) As Decimal
Private Sub btnCalculate_Click(ByVal sender As System.Object,
[Code]....
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Apr 4, 2009
I have a code which retrieves values from database
[Code]....
i want to store all the values in a array for further processing.
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May 31, 2010
I have a database in my app which loads and displays some information on a form by binding the Comboboxes and Textboxes. However, I need to get some of the other values from the database for calculations before they are displayed on the form and I can't seem to find out how to do this.I could bind a couple of Textboxes to the database and then use those values to calculate, but it doesn't seem like a very efficient way of doing things.The dataset is created using the wizard and the controls are linked in the UI.
Please bear with me, I'm still a noob.
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Jul 12, 2010
My application sends information from Form1 to Form2 by means of a global variable on Form1 whose value is read by Form2.
This variable is basically used to tell Form2 what it has to do because it's value will change depending on different conditions.
All form2 is meant to do is load data from a database into DataSets which will "ported" to Form1 (the main form) for consumption. I use a Form for this rather than a class because there's a lot of data that will be loaded each time it's visible and I wanted[code]...
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Apr 8, 2009
I have a rich text box and i want to enter 10 values and I want to use this button I have to store it. How can I do this? Or can anyone link me to the Microsoft site with information about this? (this is visual basic in Visual studio 2008)
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Sep 13, 2010
I am a beginner at VB.net programming. this score calculator. The application is suppose to total up a sum of numbers added, show the count, and an average of the numbers inputted. I try using an array to store the inputted values. Now I'm have issues with my loop keeping track of the total. Also, how do I clear out the array to start over?
[Code]...
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Jul 18, 2009
Using VB express 2008 here. I am just wondering about the best way to store certain values like the last browsed folder even if a user closes the app and starts it again. I dont want to go the route of making a text file in the installation directory and storing the values there. Seems clunky.
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Oct 11, 2009
I want to store say like 8 values, that in the end will be combined into one string. What's the best way to store them? They should be reached in a own namespace I did. In a separate .vb file. I want to able to edit them. The values are both text and numbers. So whats the best way according to you?
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Feb 18, 2012
i think its hard to explain, but here we go.I have a combobox, where you should be able to add item (in this case colors/Hexcode selected from colordialog).So lets say we have 3 items in that combobox:and if you pick blue, the color blue should apper in a background color.I can only get names to work, but i cant find out how to store the hex value data.
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Apr 1, 2010
The following is the code i used to get the value from textbox to listbox and store all the listbox values to the access database at the runtime.In the database, i have only one field called num which is been set as a multivalue field using the lookupwizard. But actually what happens is ,no error is occurred,but the value is not updated in the batabase.
vb.net
Imports System.Data.OleDb
Public Class Form1
Dim conn As OleDbConnection[code]...
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Jun 21, 2010
I need information about store procedure in SQL and how can i access textbox values into store procedure. and connection string for remote server (sql server 2005 installed on server)
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Mar 21, 2011
is that instead of receiving data from one row and assigning it to the same array Im receiving data from multiple rows, but the information is the same because its from the same one column from the database. The error I keep getting is 'index out of bounds of array'
here is the code
What it does is it loops through once and retrieves the first value from the db then it throw the exception when it goes to retrieve the second value.
Dim qBkNum As String = "SELECT BookingNum FROM Bookings WHERE BookingID = '1'"
Dim bkNum(5) As String
Try
[Code].....
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