ByVal copy a variable
in [VB.NET]
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From: Michel Posseth [MCP] on 28 Apr 2010 14:17 Hello Miro You might find this generic code interesting ( i made it in VB 10 but just convert the auto property to a normall property and it will also work in VB 2008 ) The solution for your propblem is the cloneobject method regards Michel 'Michel Posseth Option Infer On Option Strict On Option Explicit On Imports System.IO Imports System.Runtime.Serialization Imports System.Runtime.Serialization.Formatters Imports System.Runtime.Serialization.Formatters.Binary Public Class BinarySerialization Public Sub SerializeToFile(Of T)(ByVal path As String, ByVal obj As T) Using fs As New FileStream(path, FileMode.Create) bf = New BinaryFormatter(Nothing, New StreamingContext(StreamingContextStates.File)) bf.Serialize(fs, obj) End Using End Sub Public Property bf As BinaryFormatter Public Function SerializeToMStream(Of T)(ByVal obj As T) As MemoryStream Using ms As New MemoryStream(2048) bf = New BinaryFormatter(Nothing, New StreamingContext(StreamingContextStates.Clone)) bf.Serialize(ms, obj) ms.Seek(0, SeekOrigin.Begin) Return ms End Using End Function Public Function SerializeToByteArray(Of T)(ByVal obj As T) As Byte() Return SerializeToMStream(obj).ToArray End Function Public Function DeserializeFromFile(Of T)(ByVal path As String) As T Using fs As New FileStream(path, FileMode.Open) bf = New BinaryFormatter(Nothing, New StreamingContext(StreamingContextStates.File)) Return DirectCast(bf.Deserialize(fs), T) End Using End Function Public Function DeserializeFromMstream(Of T)(ByVal ms As MemoryStream) As T bf = New BinaryFormatter(Nothing, New StreamingContext(StreamingContextStates.Other)) ms.Seek(0, SeekOrigin.Begin) Return DirectCast(bf.Deserialize(ms), T) End Function Public Function DeserializeFromByteArray(Of T)(ByVal buffer As Byte()) As T bf = New BinaryFormatter(Nothing, New StreamingContext(StreamingContextStates.Other)) Using ms As New MemoryStream(buffer) ms.Seek(0, SeekOrigin.Begin) Return DirectCast(bf.Deserialize(ms), T) End Using End Function Public Function CloneObject(Of T)(ByVal obj As T) As T Using ms As New MemoryStream(2048) Return DirectCast(bf.Deserialize(SerializeToMStream(obj)), T) End Using End Function End Class "Miro" <miro(a)beero.com> schreef in bericht news:ual7L0u5KHA.3292(a)TK2MSFTNGP06.phx.gbl... > Hi, > > (vb.net vs2008) > > I understand the significance between memory pointers with a function > using byVal and byRef. > > However I have code that I want to do something like this: > > Dim UsMailmsg As MailMessage = EmailOrderClass.createEmailOrder(False, > cartOrderID) > For nI As Integer = 0 To SendToEmailAddresses.Count - 1 > EmailOrderClass.sendEmailOrder(CustomerAddress, > ToEmailAddress, UsMailmsg) <------- this line > > Now When I am using the UsMailmsg, even though the function is specified > as "byVal" it will always pass in as a reference to a memory pointer. > How do I pass it in as a 'Direct Copy' of the variable. > > So basically I can create an 'orig' version of the UsMailmsg, then it > passes a copy of it into a function where that function changes parameters > left and right. > But on the next "for next loop" it will send in the orig for the next run > of something else. > > Hope that makes sense. > > Thanks, > > Miro > > >
From: Miro on 28 Apr 2010 20:19 Thanks tom - I will pull out my vb.net book and try to do some reading. Many thanks, Miro "Tom Shelton" <tom_shelton(a)comcastXXXXXXX.net> wrote in message news:e#FWeFv5KHA.5016(a)TK2MSFTNGP02.phx.gbl... > On 2010-04-28, Tom Shelton <tom_shelton(a)comcastXXXXXXX.net> wrote: >> On 2010-04-28, Miro <miro(a)beero.com> wrote: >>> Hi, >>> >>> (vb.net vs2008) >>> >>> I understand the significance between memory pointers with a function >>> using >>> byVal and byRef. >>> >>> However I have code that I want to do something like this: >>> >>> Dim UsMailmsg As MailMessage = EmailOrderClass.createEmailOrder(False, >>> cartOrderID) >>> For nI As Integer = 0 To SendToEmailAddresses.Count - 1 >>> EmailOrderClass.sendEmailOrder(CustomerAddress, >>> ToEmailAddress, UsMailmsg) <------- this line >>> >>> Now When I am using the UsMailmsg, even though the function is specified >>> as >>> "byVal" it will always pass in as a reference to a memory pointer. >>> How do I pass it in as a 'Direct Copy' of the variable. >>> >> >> The common way would to implement the IClonable.Clone method - which >> would >> return a deep copy of the object. >> > > Building upon this - you should realy take a combination of mine and Cor's > replies :) A common way to make a deep copy of an object is to serialize > it > to a memorystream and then desearialize from the memorystream.... > > -- > Tom Shelton
From: Miro on 28 Apr 2010 20:19
I didnt want to do a "new" as within the "new" function I do a lot of calculations for 'defaults' that I would rather not do through each itteration. Thats why I want to setup a 'base original' and then just copy from there. Cheers' Miro "AMercer" <AMercer(a)discussions.microsoft.com> wrote in message news:FF8D93B1-8FBD-41FA-8CB9-9DFA4F4A4D62(a)microsoft.com... > As I understand your question, you need to create a new object, pass it to > sendEmail Order(), and then discard it. Perhaps new object could be > created > by calling createEmailOrder(), or perhaps by UsMailmsg.MemberwiseClone(), > or > perhaps you need to write a custom cloner. Regardless, if sendEmailOrder > changes object properties and you want to ignore them, then you need a > fresh > (new or cloned) object at each iteration. > > AMercer > > "Miro" wrote: > >> Hi, >> >> (vb.net vs2008) >> >> I understand the significance between memory pointers with a function >> using >> byVal and byRef. >> >> However I have code that I want to do something like this: >> >> Dim UsMailmsg As MailMessage = EmailOrderClass.createEmailOrder(False, >> cartOrderID) >> For nI As Integer = 0 To SendToEmailAddresses.Count - 1 >> EmailOrderClass.sendEmailOrder(CustomerAddress, >> ToEmailAddress, UsMailmsg) <------- this line >> >> Now When I am using the UsMailmsg, even though the function is specified >> as >> "byVal" it will always pass in as a reference to a memory pointer. >> How do I pass it in as a 'Direct Copy' of the variable. >> >> So basically I can create an 'orig' version of the UsMailmsg, then it >> passes >> a copy of it into a function where that function changes parameters left >> and >> right. >> But on the next "for next loop" it will send in the orig for the next run >> of >> something else. >> >> Hope that makes sense. >> >> Thanks, >> >> Miro >> >> >> >> . >> |