Reflection - Getting A Reference To A Class By Its Name
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
When I got a fieldsinfo-array of a class I know all of it's fields. Now, how can I access all of the fields of an instance of the same class by using the fieldsinfo-array? [code]I'm sure there exists a possiblity to get the value of the instance, but how?
I'm trying to use reflection to populate the properties of an array of a child property... not sure that's clear, so it's probably best explained in code:
Parent Class: Public Class parent Private _child As childObject() Public Property child As childObject() Get Return _child [Code] .....
The issue is now trying to get that array assigned to the parent object (using reflection). It shouldn't be difficult, but I think the problem comes because I don't necessarily know the parent/child types. I'm using reflection to determine which parent/child is being passed in. The parent always has only one property, which is an array of the child object. When I try assigning the child array to the parent object, I get a invalid cast exception saying it can't convert Object[] to.
Basically, what I have now is: Dim PropChildInfo As PropertyInfo() = ResponseObject.GetType().GetProperties() For Each PropItem As PropertyInfo In PropChildInfo PropItem.SetValue(ResponseObject, ResponseChildren, Nothing) Next ResponseObject is an instance of the parent Class, and ResponseChildren is an array of the childObject Class.
This fails with: Object of type 'System.Object[]' cannot be converted to type 'childObject[]'.
I know its unlikely but I was wondering if there is any way to get the comments (i.e. the bits after the ''') of a class or property..? I have managed to get a list of properties of a class using the PropertyInfo class but I cant find a way to get the comments / description.. I need it for a guide I am writing for the administrators of my site - it would be great if it could automatically update if new properties are added, so there is no need to worry about updating it in the future too much.
how to create an instance of a class then add properties to the class, set those properties, then read them later. I don't have any code as i don't even know how to start going about this. C# or VB is fine.
My system has a dynamic form creator. one of my associates requires that the form data be accessible via web service. My idea was to create a class (based on the dynamic form) add properties to the class (based on the forms fields) set those properties (based on the values input for those fields) then return the class in the web service.
additionally, the web service will be able to set the properties in the class and eventually commit those changes to the db.
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent() Dim resources As System.ComponentModel.ComponentResourceManager = New System.ComponentModel.ComponentResourceManager(GetType(_Class))
[code]....
How can I reach that sqlparameter collection via fieldinfo or other related classes in >NET Reflection?
What I wanted to do was, given the table name (as string), use reflection to instantiate the get method for specific fields (defined as properties with Get and Set methods.
Dim target As Object ' target gets properly set to something of the desired type Dim field As FieldInfo = target.GetType.GetField("fieldName", _ BindingFlags.Instance Or BindingFlags.Public Or BindingFlags.NonPublic) field.SetValue(target,newValue)
This snippet works perfectly IF target is set to an instance of a CLASS.However, if target is set to an instance of a STRUCTURE, the code does not actually change the value of the field. No error, but the value remains unchanged.And, oddly, if I'm stepping through code, watch the SetValue fail to do anything, and immediately go to the Immediate window and type exactly the same SetValue operation, that works.
Edit:
Per request from Jon Skeet, actual code: Private Shared Function XmlDeserializeObject(ByVal objectType As Type, _ ByVal deserializedID As String) As Object[code].....
I want to retrieve private (implementation and other) methods of a class which implements an interface and also is derived from (inherits) a base class.How can I achieve this using reflection?This is wat m tryin to do. I need to view these private methods and their contents, I don't want to invoke them.
Dim assembly As System.Reflection.Assembly Dim assemblyName As String assemblyName = System.IO.Path.GetFullPath("xyz.dll") assembly = System.Reflection.Assembly.LoadFile(assemblyName) assembly.GetType("myClass").Getmethods(Bindings.NonPublic) assembly.GetType("myClass").GetMethods(BindingFlags.NonPublic) isn't working
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")
I know that the MenuItem class contains an internal class named MenuItemData, which contains itself an internal member named onDrawItem. Given a MenuItem, I want to retrieve the object corresponding to the member onDrawItem. But all I manage to do is to get the FieldInfo, not the object itself.
Here is my code: Dim obj As Object Dim fi As FieldInfo Dim item as System.Windows.Forms.MenuItem Dim mType As System.Type [Code] .....
I am working on a project where my class has to execute VB code provided by the user, to make it simple I am trying to recreate my own eval function, I am using the following code I found on the web to do this task.
The problem with code is that it can't access any variables or there values, so I have decided to get the variable names, there values types and there types dynamically and recreate them in the class that is being created dynamically. Any way to get the variable names there types and values in the current class or method, so that I can recreate them, and execute the user passed code, the user knows what variables are in the current class or method and there datatypes but he don't know there values as they may have changed, so he can't initialize them. Is there a way to do this, this code will be called in an asp.net page on page_load event, the code passed by the user is stored in the variable vbCode that is passed as a parameter.
I'm trying to make a very simple audio tag editor. The idea is that the user can select as many audio files as he likes from a ListView, and a PropertyGrid will then display their tags + their values.When multiple files are selected, I want the property grid to display the values of the tags that all files have in common, and display empty values for tags that the files do not have in common.As an example, look at the properties list in your Visual Studio IDE when you select multiple controls (of the same type for this matter). Select a few Button controls, for example, and notice that the properties whose values are the same (often things like Font, ForeColor, etc) are displayed. Also notice that the values for properties that are not the same (Text, Name, etc) are empty.
Within the Company.Project.vbproj assembly, I have a class FriendClass.vb which scope is Friend (internal in C#).Now I wish to test this FriendClass.vb from within the Company.Project.Tests.vbproj assembly. I know about the InternalsVisibleToAttribute, but that is not an option in Visual Basic .NET 2.0, as it is only available with C#, in .NET 2.0 (see here).I would like to create myself a proxy class using this internal FriendClass from within my testing assembly, so that I could instantiate it and do the testings accordingly.
I am just curious, if there is some way to attach handler to my derived classes base event, if I know EventInfo and I have Delegate to handler function. I have tried MyEvent.AddHandler(CType(Me, BaseClassType), MyDelegate) already, but no positive result at all. Consider being in need of attaching handler to custom event at runtime, while derived class possibly shadows this event.
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:
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.
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
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
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 ?
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
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.
I have had several occasions recently to access a specific class several times over a relatively small time frame.So I've been storing the value of the class in Session and trying to access it on page load, if it's not available creating a new instance and storing that in session.
So instead of constantly replicating the same code for different classes on different pages I'm trying to create an extension method to do this for me.
[Code]...
I'm stuck on what to do when I make my new instance of my class (it would have to have a New() sub)
I'm not sure where to go from here... or even if this is the best way to do it.
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
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?
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.
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:
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.
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"?
