Pass The Property Of An Object To A Function ByRef
Jul 16, 2009If you pass the property of an object to a function ByRef, and the function doesn't modify the ByRef parameter, the property Set is still called.
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If you pass the property of an object to a function ByRef, and the function doesn't modify the ByRef parameter, the property Set is still called.
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Below I tried to do an Example:
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Below is the called method: Friend Sub SplitOU2(ByVal inDN As String, ByRef OUDN As Object, ByRef Organisation As Object, ByRef VerksamhetTyp As Object) By doing this I can skip to declare the in this example "useless" variable Dim VerksamhetTyp as Object = "".
Why if you pass an object as byVal into a method is it then treated as if it were byRef? I know you're only passing the reference across when you pass an object variable but why doesn't VB force you to decalre the header as byRef?
View 2 RepliesI work with C# 99% of the time. However, I'm having to update some legacy VB.Net code and encountering an issue with VB.Net code syntax. The error that I get is "ByRef" is underlined and "Expected Expression" tag shows up when you hover over "ByRef". The "FooDetail.Load" function is written in C# and expects a List object passed as reference. Don't have any trouble using the same function in other C# classes. Can someone indicate what is wrong with below VB.Net code.
Dim FooDetail As New clsFooDetail()
FooDetail.FooID = FooID
Dim lstFooDetail As New List(Of clsFooDetail)
FooDetail.Load(ConnectionString, "Stored Procedure", ByRef lstFooDetail as System.Collection.List(Of(clsFooDetail))
I am working on a application that has quite a few functions involved and have been thinking of the following: If I have a function that has a few paramaters, is it more efficient to pass the objects to the function(Example 1) or reference the objects in the parent(Example 2)? Does it matter if the objects are large or not?
Example:
Class mainform
Public myGenericList As New List(Of String)
Public myDatarowArray() As DataRow
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I'm trying to give a default value to the register property method. This required a function, but passed as an object(delegate?).[code]....
I want to call that registerproperty method, but I don't know how I can do that in VB.net. I just need to pass along a new Person object and I thought this was the way to go[code]....
How do you pass a control (say a textbox) to a function as a parameter in compiled assembly using CodeDom? I've tried passing through the args in the Invoke method but it doesn't work.[code]...
View 6 RepliesI am making use of a 3rd party dll and am encountering some strange behavior in VB, which doesn't occur in C# Perhaps someone can explain what is going on. Anyhow, I am making use of a method in this 3rd party library which accepts an array parameter ByRef. The end result is the variable should remain null after the method call, but it is returning initialized for some reason.
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Is it considered bad practice (VB.NET or any language) to code a function with both ByVal and ByRef parameters as used in my getFile function below?
Function getFile(ByVal channel As Integer, _
ByRef Filename As String, _
ByRef Filesize As String) As Integer
End Function
Dim status As Integer
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So if I create an object test, and it has a property color. When I add this object to an array list I typically can access this using myarray(0).color but intellisense doesn't 'know' that I have a 'test' object inside the array. It would let me type myarray(0).whatever but would then crash if I made typo. It seems like I should be able to let it know what type of object I am trying to work with inside the arraylist. In code maybe something like this
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I have a legacy COM-component with an interface declaring a property like this (IDL notation):
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This interface is implemented in a calling application written in VB6 like this:
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Everyting works fine until I try to do the same in VB.Net. VB.Net refuses to compile code where a parameter of a property is passed ByRef. MSDN says VB.Net doesn't allow such parameters. Is there any way I could implement such a property in VB.Net?
I have a 3rd party (c#) class that raises an event. on accsing this event i want to copy the image property to a queue.
Dim myQ as queue
Private Sub imageprocessor_NewImage() handles camera.NewImage
myQ.Enqueue(imageprocessor.currentimage)
End Sub
But when I view myQ at a later date it tells me the parameters of the images are not valid.Is it adding them by reference?i would have through adding an object to a queue was byval. how can i enforce this?
I want to make an numerical integration method with takes in an analytic function and integrate it over a specific interval. For the numerical integration procedure I want to use some procedures in nr.com. The problem is that these are programmed in C++ and they uses functors to pass a function to the integration method. How can I do this in VB 2010?
I want to initialize the function (i.e. set a=1,b=0 for function y(x)=a*x+b) and then pass the function to the integration method. Then when the integration method call the function it only calls the function with one parameter (i.e. x since a,b is already set)
What is the best way to do this in VB2010?I want to make a general integration method where I can pass any single valued function and integration limits.
I have just started using VB, and from what I have found so far it seems like the tools you have is
- to us a delegate for the function
- to use a lambda expression for the function
- send a pointer/adressOf
- to create a function class/structure and submit this to the function
As for now I am most inclined to create a function-class. But I am not really sure how.F.ex. I make different classes for each "uniqe function" I want to integrate, but how can I pass them to the integration function when I need to specify the argument type in the integration-function-call?This seems like a basic problem which applies to many Math operations, so I think it would be very useful to clarify this.
Can a function return a value byref instead of the default byval? That is to say, allow me to directly edit the variable that it is retrieving instead of just giving me a copy of that variable.Right now I'm trying to write a function that will return, based on what the user has selected through a combobox, a particular setting (eg. My.Settings.somethingHere). I then want to be able to edit the setting directly through just calling the function. Is that at all possible?
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How can I get the name of the object that was passed byref into a method?
Example:
Dim myobject as object
sub mymethod(byref o as object)
debug.print(o.[RealName!!!!])
end sub
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I'm using this for logging. I use one method multiple times and it would be nice to log the name of the variable that I passed to it. Since I'm passing it byref, I should be able to get this name, right?This would give you the parameter name in the method and it's type, but not the name of the variable that was passed byref.
using system.reflection
Dim mb As MethodBase = MethodInfo.GetCurrentMethod()
For Each pi As ParameterInfo In mb.GetParameters()
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If you put that in "mymethod" above you'd get "o" and "Object".
is there any collection in vb.net which store object as byref and not byval.
View 4 Repliesim parsing an xml file using this code Private Function overview2(ByRef filePath As String)Dim reader As XmlTextReader = New XmlTextReader(filePath + "\movieData.xml")
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it works 80% of the time. What i mean is , i go through each node and when i find the overview node i read the data and send it to a text box. Im doing this for movies on disk. sometimes on certain movies it doesnt find the overview node even though it is there .
I'm currently invoking a function that takes ByRef parameters using Control.Invoke (which I notice specifies the Object parameter array to be ByVal) but the array of parameters I give it isn't updated by the function. Is this possible with VB.Net 2003 or must there be some error in my code?
View 5 RepliesIs there a Limit to the parameters that can be passed byVal or byRef to a function or procedure in vb .net ?
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I have a WCF Service exposing a single contract and operation:
<ServiceContract(Namespace:="ImageSystem")> _
Public Interface IUploadService
<OperationContract()> _
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This subsequently leads to stream casting issues, because the generated function allows me to pass a memory stream as an input (which works correctly when passed through to the service), but instead of passing me back a new stream for the response, it attempts to cast the MessageBodyStream received from the service into my memory stream.
This is, in some ways similar to other posts but as you can see, there are no enums involved in my contracts - presence of Enums caused strange proxy class generation is marked as the answer in the similar post.
Is there anywhere I configure the proxy behaviour to use the contracts I've specified? Clearly I'm within a dev/test environment currently, but when this eventually goes to production it will be memory and file streams passed to the service, and the returned stream can be in any format to be honest, I intend to treat it as the abstract stream class. The only way round this I can see right now is to change my in stream to be the same as the anticipated out stream, but surely there is a better way?
I was shocked just a moment ago to discover that the following is legal (the C# equivalent is definitely not):
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I've got a f(x) that returns a collection of user controls. .Net lets me just treat the f(x) name as the collection.
ex)
Private Function GetCcB() As Collection(Of Reports_ucColumn)
Dim cc As New Collection(Of Reports_ucColumn)
cc.Add(Me.ucColumn0)
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I want to make a GetAllContacts method which takes a sort parameter of type Func(Of Contact, TKey) which is the same type that the OrderBy method for an IEnumerable(Of Contact) takes.[code]"Too many arguments to extension method 'Public Function ElementAtOrDefault(index As Integer) As Contact' defined in 'System.Linq.Enumerable'." on the second parameter.
View 2 RepliesIm a student doing an assignment, how do i pass the value from a sub procedure to a function procedure....i want to pass the value from decSubtotal to a function procedure named CalculateDiscount; check out my code--
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I searched on the forum / Internet for the solution how a PropetryInfo object (of a Public property) can reveal if it has a Private Protected Setter ... it was all in vain .... all help I found was about how to "Set" value of a public property having a Private Setter.I would like to know if I have a PropertyInfo object of a public property, how would I know if its Setter is Non Public?
I tried, in a exception handling block, where I did a GetValue of the PropertyInfo object and then called SetValue by setting the same value back... but to my surprise it worked well and didn error out.
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on a Windows Form, an object myObject is bound to myObjectDataBindingSource like this:myObjectDataBindingSource .DatSource = myObject on the form, i have a check box bound to the property: chkProp1 for example of the object: myObjectDataBindingSource In the code when the checkbox is clicked, I need to go in code and change another text property of the object txtProper2 for example like this:
Private Sub chkProp1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkProp1.CheckedChanged
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I have some classes, BsfciFile and StudyFlashCard. Bsfci is the extension to which I save my set of flashcards in an INI format. I am currently working to transform my code from using Windows API calls to access the INI to using a IniFile class that I found on the internet. I would like the BsfciFile to have a Array of StudyFlashCard objects, but I would like the StudyFlashCard class to use the IniFile class object contained in the BsfciFile class. I can pass the IniFile from the BsfciFile class to the constructor for the StudyFlashCard class, but I want it to modify the same IniFile as the BsfciFile class has later on.
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I have a listbox of a object called Account, which has 2 fields, password, and username. How can I compare a New Account to all the accounts in the list and see if the password matches?
View 3 RepliesHi
I've got a pretty general question about the best practice in passing an object reference to a Form in VB.NET. My form is a dialog and I've created an overload ShowDialog method, where I pass an Object into it ByRef.
The trouble is, I want to be able to refer to that Object throughout my dialog Class and not just in the ShowDialog method. For instance, some of my Events for controls on the form, need to reference that object.
I know I could create a local Private variable in the Class and assign it to the passed value, and then use that value. However I'm thinking this isn't very efficient because it would (I believe) create a new copy of the Object (which is a complex, large class in itself).
I know how to handle a single objects property changed event very easily. I want to handle a objects property changed event that is part of another object.
Given Object:
[ObjectY = Y]
+ Public WithEvents X As ObjectX
I would like to do something like:
Private Sub XPropertyChanged() Handles Y.X.PropertyChanged
Right now I need to create a object that equals the object inside that object and then handle this variable pointers property changed, but that is just annoying.