Invoking A Class Without Having A Reference?
Mar 17, 2009
I'm converting a VB6 app to vb.net.The code creates objects using the CallbyName function with the classes name & and method being read from a database.I want to rewrite the classes in vb.net and have the same behaviour as I read in the name of an object from the database, instantiate it, and call one of it's methods.I don't know ahead of time what the names of the classes will be, so I can't make a reference to them in my project.
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Oct 15, 2010
I'm making a little program in where i'm trying to invoke a method from a class dynamically with so called Reflection.The class I'm trying to call is called ContactList and i try to invoke the method in this class called count. The assembly itself is called Contact.ExeNow I have the following code:
Public Function InvokeContacts() As Integer
Dim ContactsAssembly As Assembly = Assembly.LoadFrom("Contacts.exe")
Dim Mycontactlist As Type = ContactsAssembly.GetType("ContactList")
[code]....
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Jan 18, 2011
my proble is the following: I have a class MyClass and another class Modifier, which has a method ModifyMyClass(ByRef mc as MyClass) that receives a MyClass instance as ByRef parameter to modify it. A smell of the code is:
[Code]...
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Apr 11, 2009
I have a 'property management class' that contains several functions and properties. I have several other classes that use the 'management class' as a property to derive the value of several of its other properties.Is there a way for me to reference the outer class from the 'management class' functions without having to pass it as a parameter? I ask because several different classes can have this 'management class' as a property and am having a hard time typing the parameter.
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Aug 19, 2009
I have a class in which some of the fields are also classes.I can put values in the "normal" properties, but in the others when o try to assign values it gives the: "Object reference not set to an instance of an object"But the code compiles fine.
dados_Defenicao = New ServiceReference1.draftClaimEntryDefinition
dados_Defenicao.arCode = "123"
dados_Defenicao.claimMarket.warrantyType = "w" - Here it gives the error
How can i fix this ?
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Aug 19, 2009
I have a class in which some of the fields are also classes.
I can put values in the "normal" properties, but in the others when o try to assign values it gives the: "Object reference not set to an instance of an object"
But the code compiles fine.
dados_Defenicao = New ServiceReference1.draftClaimEntryDefinition
dados_Defenicao.arCode = "123"
dados_Defenicao.claimMarket.warrantyType = "w" - Here it gives the error
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Dec 10, 2010
If we are within the derived class then ofcource we can use MyBase keyword to access base class's object reference . That's fine , how can we take that base class's object reference outside that derived class's definition.My following code will explain what i want . Actually that is giving error right now, but it is explaining my requirement .
Public Class Base
Public x As String
End Class
[code]....
Actually there is error in ReadOnly Property BaseReference's Getter . Error is "Error 1 'MyBase' must be followed by '.' and an identifier. " how can i get base class object reference in Main method ?
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Jan 2, 2010
I have a Parent Class Called Fuselage that containsfour child classes called Forebody, CenterBody, AftBody, and CrossSection. CrossSection classcontains objects common to Forebody, CenterBody, and Aftbody (example: width). How do I access thewidth property in CrossSection from within the classForebody?
Public Class Fuselage
Dim Forebody As ClsSection
Dim Centerbody As ClsSection
[code].....
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May 20, 2010
I need to create a new instance of a class that needs a member of the calling class. But i can't pass a reference to the calling class through the constructor.The solution i am looking for is something like this:
Public Class ChildClass
Public Sub New(args)
_MyMember = GetMemberFromCallingClass()
[code]....
I want this to work without having to manually pass any references or variables from the calling class to the new instance of ChildClass.
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Mar 17, 2012
The book "Beginning ASP .NET 4 in VB 2010" contains the following:NOTE: TaxableProduct inherits from Product.You can also cast in the reverse directionfor example, cast a Productreference to a TaxableProduct reference. The trick here is that this
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Sep 15, 2009
how can I add a class of a different project to my current project as a reference?I tried Right click_-> add existing item --> ( The class from the other project) then it gives me error.I am not sure how can I use that class as my reference to my current project?
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Sep 6, 2010
I'm trying to use reflection to get the instance of a class in vb.net. I have a class 'A' in my web project and to test it, i create a new aspx page and try to write the following:
Dim t as Type = Type.GetType("A")
This returns "Nothing". But if i do this:
Dim inst as A = new A()
Dim t as Type = inst.GetType()
t's type is "A"
So how come i can't get the type with GetType even if the name is exactly the same? It does works for things like System.Math though
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Aug 6, 2010
This is an ASP.NET 2010 web app written in vb. I use several Session variables. I want to pass them all to a central class and let the class manage them. However, I am having some trouble. Here is the code on the calling page:
Dim arrGoodSessions() As String ={"nameofsession1", "nameofsession2", "nameofsession3"}
Utilities.ManageSessionVariables(arrGoodSessions)
It calls that static Utilties class. I have set a reference to System.Web. Here is the code in the class:
Imports System.Web
Imports System.Web.SessionState
Imports System.Web.SessionState.HttpSessionState
Imports System.Web.HttpContext
[code]....
This attempts to simply read in some names of session variables and then cycle through all session variables and remove any I didn't list. This works when all of the cod eis on the page. But when I move this to the class, it doesn't recognize Session.Contents.
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Dec 25, 2011
Class1:
Dim v as integer
public sub storeVar(byval s as integer)
v = s
end sub
[code].....
I need to save a reference of variable s in Class2 in variable v in Class1.(i.e. when the value of s changes v also changes (and vice versa)Is this possible since vb.net doesn't have pointers?Will it work if I change "byval" to "byref"?
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Oct 28, 2010
I have a web site project where I need to use the System.Security.Cryptography.Xml.SignedXml class. I added the Dll System.Security as a reference and imported the namespace into my project. It compiles successfully but when I debug the project I get a compilation error:
Compiler Error Message: BC30002: Type 'System.Security.Cryptography.Xml.SignedXml' is not defined.
What gives? Edit: I run Windows XP Pro 64bit OS
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Aug 21, 2011
I'm converting a pretty large chunk of code into a Class so that it can be re-used more easily, but am having a problem with one of the Methods. I have a method that uses the following line:'GET HANDLE OF ANY POPUP WINDOW ASSOCIATED WITH MAIN FORM [code]The "Me.Handle" part won't work, but I don't know what to replace it with so that it knows to use the handle of the main application's form that is using the Class.Do I need to get all Process that match my application's and store the Process' handle?
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Apr 5, 2011
I have a class that I would like to link at construction to a given control (say a textbox)
I know I can put a variable into a subroutine referentially but is there a way to store it in the same capacity?
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Jul 19, 2011
Let's says I have a class called Customer :-
Code:
Dim Cust as New Customer("Fred")
I also have a function in a seperate class :-
Code:
Shared Function Example(Example As Customer)
How do I refer to the class itself from within itself? For example :-
Code:
' from within the Customer class, call the Example function
AnotherClass.Example(Me??)
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Apr 30, 2010
Public Class Form1
Public Contestant As New ContestantClass
Public HighScore1 As New ContestantClass
Public HighScore2 As New ContestantClass
Public HighScore3 As New ContestantClass
[Code] .....
The problem I'm having is the first time I take a value, it gets inserted in the right section. The second time I insert a value, it inserts it in the correct place AND updates the previous value I inserted with the new value. So apparently when I'm doing:
HighScore1 = Contestant
It's pointing contestant AT highscore1 rather than taking the name, company, and score from contestant and then storing it in highscore1. How I can pass that info by value rather than by reference?
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Nov 7, 2011
I've created a function in my vb class file that creates dynamic tables. I'm planning to use this to create tables dependent on a button being clicked. The function references a placeholder in my aspx page but I'm getting "placeHolder1 is not declared".How can I access controls on my form from my class file? [code]
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Sep 19, 2010
I have created an ASP.NET class. In that class i would like to use the Server.UrlEncode. Why intellisense is not helping me at all and instead of Server.UrlEncode it displays the HttpServerUtility? I have already a reference to system.web
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Oct 14, 2011
I have an ASP.NET website written in VB.NET and trying to add MVC to it.
I managed to add controllers (to CS_Code folder) and make them running. However, I have to use some code from aspnet pages.
When I try to call method from page I ma having compile time error
public CustomerFrontend.DefaultForm DefaultForm { get; set; }
Error:
The type or namespace name 'DefaultForm' could not be found (are you missing a using directive or an assembly reference?)
Page directive definition which proves than namespace is correct:
<%@ Page Language="vb" ValidateRequest="false"
EnableViewState="False"
AutoEventWireup="false"
Inherits="CustomerFrontend.DefaultForm"
CodeFile="DefaultForm.aspx.vb" %>
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Dec 30, 2011
I have a solution built of 3 projects:
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Feb 17, 2010
I am trying to build a dynamic validator for a data entry application. I want to be able to query a table for the validators relating to the current task and then be able to reference class properties based on the description of the validators returned.
ex. Validator = "person/firstname"
How do I get to _clsPerson.FirstName?
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Feb 13, 2012
If we are within the derived class then ofcource we can use MyBase keyword to access base class's object reference . That's fine , how can we take that base class's object reference outside that derived class's definition.
My following code will explain what i want . Actually that is giving error right now, but it is explaining my requirement .[code]...
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Aug 5, 2011
I have a class file framebuild with a class command and class commandlist(of command). I fill the comandlist with a method in the class commandlist, to do that I make in the class commandlist a new instance of commandlist. But now in form4 I want to make a listbox which represents the commandlist. Then I also should make a new instance of a new instance? It is no problem to fill the list in the class instance but I want to fill it in the form.vb
Public Class rts485command
Property name As String = ""
Property hexname As Byte = &H0
Property framelength As Byte = &H0
End Class
[Code] .....
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Feb 14, 2006
I have an app (vb.net) that sues multi threading and have tow problems.
1. The program is used for trading currency markets and mointers prices all day. When a signal is generated it wil place a trade in a new thread. In the new thread it checks to see if a trade is on already and if so it will not place another trade.The problem is it can be too fast and place another trade before the server has processed the first trade. So trade count returns 0. As the system watches 6 accounts I can not just pause the other thread to make sure it has finished before trying ot place another trade.How to i check to make sure the first thread is finished so when i check for trade count it retuns 1?
2.The new thread is inside a class and has a logging class as well. The problem is writing to the text box on the main thread. As the logging thread is created in the new thread it has no access to the textbox. I have tried using invoke but it still does not write to text box as it does not exist in the new thread.How do i reference a form from a class that was created in a new thread?
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Mar 12, 2010
Is it possible using Reflection or some other method to obtain a reference to a specific class instance from the name of that class instance? For example the framework for the applications I develop heavily uses public class instances such as:
Public bMyreference as MyReference = new MyReference
Then throughout the application bMyReference is used by custom controls and code. One of the properties of the custom controls is the "FieldName" which references a Property in these class instances (bMyReference.MyField) as a string. What I would like to be able to do is analyze this string "bMyReference.MyField" and then refer back to the actual Instance/Property.
In VB6 I would use an EVAL or something simular to convert the string to an actual object but this obviously doesn't work in VB.net. What I'm picturing is something like this:
Dim FieldName as String = MyControl.FieldName ' sets FielName to bMyReference.MyField
Dim FieldObject() as String = FieldName.Split(".") ' Split into the Object / Property
Dim myInstance as Object = ......... ' Obtain a reference to the Instance and set as myInstance
Dim myProperty = myInstance.GetType().GetProperty(FieldObject(1))
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Jan 24, 2011
I currently have the following [code]...
How can I modify it so that "UserControl_appName" is not hard coded. I would like to pass it as a string.
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Jan 11, 2010
I created a class library of useful functions and it compiled successfully into a DLL. It works great but I need to reference the DLL by navigating to my class project.
Can't I just move the DLL into the System32 folder and point to that reference? Do I need to register it with the OS or can I simply drag & drop?
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