Original Value Changed While Passing Array Parameter Using ByVal?
May 31, 2009have a subroutine which parameter is an array like below:
Private Sub DoubleArrayValues(ByVal arr() As Integer)
Double the values.
[code].....
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VS 02/03 Passing Array As A Parameter?
Nov 16, 2010I'm wondering if this sort of thing is possible in VB.NET.. say I have a routine which accepts an integer array, defined as:
Sub WriteTable(iRows As Integer, arrColumns As Integer())
The arrColumns parameter is an integer array of column widths.
I can pass a value by doing this:
[code]....
VS 2005 Passing An Array As A Parameter In A Sub?
Sep 14, 2009I am working with some code that uses array lists and I am using some of these to pass data back and forth like this: whatFile = (sideLookUp(x)) and its working, BUT when I turn this code into a sub/function then I call it I get problems, like double to string errors, even though its all set to double.
[Code]...
2008 Passing In SQL Parameter Where Datatype Is Date Array (SQL Server 2005)?
Jan 28, 2010I'm attempting to pass in a collection of dates to a T-SQL 'IN' clause via a date array (see below for how data is collated).
'Workout weeks difference between start and enddate
Dim wksDifference As Integer = CType(DateDiff(DateInterval.WeekOfYear, bookingStartDate, bookingEndDate), Integer)
[code].....
Get Original Value Of Field Before It Was Changed?
May 11, 2012I'm from a Visual Basic 6/VBA background and I'm moving to VB.Net. I've got a field on a form and I want to look at the value of the field BEFORE it was changed by the user. In VBA/VB6 I simply sais Me.FieldName.OldValue to get the original value. How do i do this in VB.net?
View 6 RepliesVS 2010 Check If The Original Value Of Textbox Has Changed?
Jan 31, 2012How do I check if the original value of a text box has been modified?
I have a few textbox controls on a form. When form loads; user enters data in these fields but later change his mind and modifies what was entered earlier. I need to know which textbox or txtboxes were modified.
Force Passing Argument Byval?
Sep 16, 2010I have an old unmanaged dll function and I want to pass an array to it.The dll function expects the array to be passed by reference.Sometimes I can do that and sometimes I need to pass a pointer in a variable.Is it possible to override the declare for the function so that I could pass either the array by ref, or a pointer to it if I need to?
View 15 RepliesPassing Reference Types By Value (ByVal)
Aug 17, 2009I'm still working on the code in this thread [URL] and as I mentioned in that thread, I thought that passing objects around between methods would probably be bad for performance (perhaps not really noticeably at first but maybe if I did it enough then it could have an impact).
1. When you pass a reference type to a method using ByVal then what is actually 'copied' ? I understand that ByVal copies the object into the local method that you are calling where as ByRef passes a reference to the actual object so you can work with the original object. So when you have a Reference type and you pass this ByVal then does copy the entire object or does it just copy a 'reference' to the object?
2. When working with an object that relates to a 'physical' item, such as a file on disk or a network stream between two connected machines, then what happens when you pass it around between methods (this might be irrelevant depending on the answer to the first question) ? I mean if I have a NetworkStream object that represents the data stream coming from a remote computer, if I then pass that ByVal into another method then does that mean I am still working with the same data stream or a copy of it or what?
VS 2008 Passing ByRef Or ByVal?
Jul 23, 2010I have been working on this for a few days, and I am going around in circles. I can make the program work by including everything in the same sub procedure, but the assignment requires that I do certain tasks by using function procedures.What I need to do is take the contents of a text box, reverse the order of the first and last names, and add them to a list box. I can do that, just not by passing value from a function procedure. Here is my
View 4 RepliesByRef Vs ByVal Performance When Passing Strings
Jul 22, 2010Reading [URL] made me wonder whether the comments in there did apply to Strings in terms of performance. Since strings are copied before being passed, isn't it much more efficient (if the callee doesn't need a copy of string course) to pass strings ByRef?
[Code]...
VS 2008 Passing Parameters - ByVal/ByRef?
Dec 22, 2010I have some code that is transforming the coordinates of a line.I want to keep the original coords and I thought passing the line ByVal would be the best way.The original VB6 code used a temporary variable so that the original coords were not updated.I'm confused as when the X & y coords of 'line' are changed 'MyLine' is also changed. I had assumed only 'line' would change and 'MyLine' would remain unchanged'.
Private Sub TransformSaveLine(ByVal MyLine As LineType)
Dim P As Integer
Dim line As LineType
Dim x As Double
[code].....
VS 2008 ByVal / ByRef List Parameter
Sep 4, 2010I have a class OrderManager, that takes a parameter of type LocalFuturesList on construction. Now.. It doesn't seem to matter if I use ByRef or ByVal here.. It still references the parent class instance of it. It also doesn't seem to matter if I type New or omit it.. Probably also because it's just an address reference. But why is it like this? And what type of objects "acts" in this way? Further I find that if I change the object in the parent class by deserializing from a file (with my method call shown), then suddenly this reference is broken in some way, so the OrderManager instance now holds Nothing I believe.If my observations are correct I see two challenges:
1. How to pass a list NOT by reference?
2. How to maintain a list reference through deserialization? [code]
Passing String ByVal Into Function Without Changing Reference Value?
Jun 26, 2009I know strings are immutable, so the minute you change a string reference's value .NET makes a brand new string on the heap. But what if you don't change the value of a string reference; rather, you simply pass it into a function ByVal -- does this operation copy the string value on the heap as well? My inclination is "no," but I'd like to confirm.
For example:
Public Function IsStringHello(ByVal test As String) As Boolean
Return (String.Compare(test, "Hello") = 0)
End Function
Calling program:
Dim myWord as String = "Blah"
Dim matchesHello as Boolean = IsStringHello(myWord)
I know passing myWord by value makes a copy of the reference to "Blah", but since I have not tried to change the string itself, would it make another copy of the string on the heap?
VS 2010 : Copy This Array To A Temp Array So That The Temp Array Has All The Same Values As The Original Custom Array?
Jun 19, 2011I 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?
View 4 RepliesSame Name Only Datatype Changed In Parameter?
Aug 7, 2011I have two function having same name only datatype changed in parameter
SaveData( Byval p as byte())
SaveData(Byval p as string)
By the definition of polymorphism this should work.It does not show any compile time error but when I run the application and call the function it does not recognize it. And gives the error Function SaveData is not defined.But when I put a break point on the function it works fine.
[Code]...
Private Sub Page_Load(ByVal S As Object, ByVal E As EventArgs)?
Jun 12, 2009<script runat ="server" >
Dim objDT As New System.Data.DataTable
Dim objDR As System.Data.DataRow
[code]......
Passing A Parameter Containing '&'
Feb 16, 2012I am calling a crystal xi report from a windows form and passing 2 date parameters and a customer name. In some cases this customer name contains '&' eg Brown & Williams
In these cases my report fails and errors. if the name doesn't contain '&' it works. How can I pass the parameter with a & in it ?
Passing A Parameter To A Dataset
Apr 26, 2011I created a dataset that is getting data from an access database. Now i would like to go further and make the dataset query accept a parameter from a form datepick value. the query in my table adapter I have changed it as follows to accept a parameter on date1.[code]The code I am using in my form is as below. I get a null reference exception on the second line(Object reference not set to an instance of an object). it seems as if my selectCommand is bringing nothing.[code]
View 4 RepliesPassing A Parameter Value To DataSet.XSD?
Jun 2, 2012I have a bound DataGridView (dgvBuild) that contains data based on a "ProductID" that is derived from selecting the value from a ComboBox. How do I pass the ComboBox Value to the DataAdapter to retrieve records to reload the dgvBuild? Below is the code for theDataAdapter.This is the line that was created when I bound the DataGridView to a DB Table.
View 8 RepliesPassing An Event As A Parameter
Jun 10, 2011I need to pass an event as a parameter to a function and I'm wondering if there is any way of doing this.The reason why I need to do this is because I have a sequence of two lines of code that is littered all over my program, where I dynamically remove the handler to an event, then set the handler again. I'm doing this for several different events and event handlers, so I've decided to write a function that does this. As an example, let's say I have a combobox in my code called combobox1, and I have the handler called indexChangedHandler. In several places of my code, I have the following two lines:[code]Now, I don't want to keep on repeating the above two lines of code (or similar) all over my program, so I'm looking for a way to do this:[code]So far, the "evt as Event" part of the argument of the setHandler function is giving an error. Any ideas on the right way to do this will be very welcomed.
View 2 RepliesPassing An Event As A Parameter?
Nov 10, 2010I need to pass an event as a parameter to a function and I'm wondering if there is any way of doing this.
The reason why I need to do this is because I have a sequence of two lines of code that is littered all over my program, where I dynamically remove the handler to an event, then set the handler again. I'm doing this for several different events and event handlers, so I've decided to write a function that does this.
As an example, let's say I have a combobox in my code called combobox1, and I have the handler called indexChangedHandler. In several places of my code, I have the following two lines:
RemoveHandler combobox1.SelectedIndexChanged, AddressOf indexChangedHandler
AddHandler combobox1.SelectedIndexChanged, AddressOf indexChangedHandler
Now, I don't want to keep on repeating the above two lines of code (or similar) all over my program, so I'm looking for a way to do this:
Private Sub setHandler(evt As Event, hndler As eventhandler)
RemoveHandler evt, hndler
AddHandler evt, hndler
End Sub
so that everywhere where those two lines of code(or similar) occur in my program, I can just replace them with:
setHandler(combobox1.SelectedIndexChanged, AddressOf indexChangedHandler)
So far, the "evt as Event" part of the argument of the setHandler function is giving an error.
P.S I've asked this question on a couple of other forums and keep getting asked why I would want to set the handler immediately after removing it. The reason is because dynamically adding an event handler n-times causes the handler to be executed n-times when the event occurs. To avoid this, i.e to ensure that the handler is executed just once when the event occurs, I first remove the handler each time I want to add the handler dynamically.
You might be asking why the handler would be added several times in the first place... The reason is because I add the handler only after a particular event, say E1, in my form has occured (I add the handler within the handler of event E1). And event E1 can occur several times within my form. If I do not remove the handler each time before adding it again, the handler gets added and thus executed several times.
Whatever the case, the processing occuring within the function is not of ultimate importance to me at this time, but rather just the means of passing an event as a parameter.
Passing Delegate As Parameter
Nov 6, 2010I'd like to create a function myFunc with one parameter, which is a delegate. I should be able to call it with a delegate as parameter.E.g.[code]But how do I code myFunc, in other words, how do I enable myFunc to have it passed a delegate so that it can be called using myFunc(addressof test Func)?
View 4 RepliesArray - Remove Duplicate And Original?
Apr 11, 2010I've come unstuck on a certain point. I am trying to find a way to compare two lists and output only lines which are unique. In other words, remove both occurrences of duplicate lines.I'm relatively inexperienced with VB.NET, but this is how far I have managed to come;
Code:
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim LinksList1, LinksList2 As String
LinksList1 = Replace(RichTextBox1.Text, "#vch", "") : LinksList2 = Replace(RichTextBox2.Text, "#vch", "")
[code]....
1) search the array to find duplicates and add them to a second array, then have a second pass to remove anything which matches the second array.
2) search the array for one duplicate and store it, then search the array again to remove the duplicates, and run that process until there are no more duplicates.
Then again, I could be going about this completely the wrong way. If that's the case, feel free to knock some sense into me.
Return An Array From A Function To The Original Sub?
Oct 14, 2009I'm trying to call a function from a sub, and have it return an array to the original sub.
I currently have:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Call Registry_GetUsers()
End Sub
[code]....
Which works, but I want to loop through each of the items in users from within the original sub, not the function, as it currently does.So I need to return the array to the original sub, so I can then iterate through it from there.
.Net With Passing Parameter To Crystal Report?
Dec 12, 2009sample code for passing parameter to crysatl report dynamically in vb.net ...?
View 2 RepliesCall VBA Function With Parameter Passing
Dec 29, 2008I wrote vba function in excel and I want to call this function in vb.net with parameter passing.
View 2 RepliesError On Passing Date Parameter
Jul 24, 2010I am getting error when debugging a project. The error is as below,
"FormatException was unhandled
String was not recognized as a valid DateTime."
Highlighting the following line
[code]...
Passing AddressOf As A Parameter To A Subroutine?
Jun 30, 2011Assuming I have the following code that is iterating over controls in a panel setting various control information.Private Sub BindDataFields()
[Code]...
Passing An Optional Parameter To A Webservice
Nov 1, 2010Is there a way to pass an optional parameter to a webservice, instead of having to overload the method?If the webservice user is accessing the webservice directly, I want to do ActionA, if the user is accessing the webservice through my web interface, I want to do ActionA + ActionB.
View 1 RepliesPassing Parameter From To Stored Procedure?
Aug 12, 2010Can't seem to figure out why this is not working.
Dim Myspcmd As New SqlCommand("spDataImport", myConnection)
Myspcmd.CommandType = CommandType.StoredProcedure
Myspcmd.Parameters.Add(New SqlParameter("@FileName", Data.SqlDbType.NVarChar, 100)).Direction = ParameterDirection.Input
Myspcmd.Parameters("@FileName").Value = "Import_File.dtsx"
myConnection.Open()
[Code]...
