Instatiating a Class using a name in a String?
I have two projects as part of my solution:
Project: Font End
Project: Control Classes
In my front end project i have a string list of all the control classes. I need to instantiate the class into an object using the string name. How can I do this? The class must be of the right type and not just object?
Is it possible to instantiate a new class object within a Form Procedure where it is accessible to all other Procedures/Functions within the Form Module? For example, I have a Client Class Module that contains properties and Methods that reflect a Client DB Table. All the properties and Methods within this class are Public. So, when I instantiate a new instance within a Procedure, I declare it as such:
Private Sub cmdNewClient_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdNewClient.Click
Try
Dim client as New clsClient
[code]....
Normally, I would declare a new instance of this Class Object at the beginning of a Form Module. I'm trying to do this in order to have more control.
I hate to see the name of the class used as a string parameter like "FileDownloader" in the code, and I would like to use something like this FileDownloader.Name(), where FileDownloader is name of the class.Only problem is that I can't find out how to do that without instantiating object or creating a static method..Is there a way to get a class name in .net without having the object instance and without creating a static method that returns the name of the class?
View 4 RepliesWhen an instantiated class calls a method in the parent form class, VB.NET starts a new instance of the form class instead of calling the method on to the active one.How do I tell it that I have just one instance of my form class, or that I don't want to create a new instance of the form and just call the method on the already active form?
View 2 RepliesI am trying to get all assemblies in CurrentDomain using AppDomain.CurrentDomain.GetAssemblies() to write their FullName into a DropDownList, however if I don't instantiate them, they are not seen in returned array from GetAssemblies() in CurrentDomain.They are all added as Reference and in Reference folder of the solution. Only time I can get them from the GetAssemblies() is when I first instantiate them.How to overcome this problem with an easy and more generic way instead of instantiate them everytime when I add new Assembly, etc.Due to company policy, I have to obfuscate some parts of the images: All the assembilies are referenced in Reference folder:
View 3 RepliesThis question is about a different instance that im trying to instantiate...I have to get the "Read" function from my Cardreader class and return a string to it on the form1.vb .... Now i did what i can remeber but for some reason i'm having a problem with the brackets.... What can i do to fix this?Form1.vbThisATM.getCardReader.Readr("TEST TEXT IS FUN")
CardReader.vb
Public Function Readr(ByVal card As KeyCard) As String
Return Read
[code].....
I am in the middle of (trying) to create a Class Library available for use in VB6/VBA. With some assistance received here I have now done the following:Created a Class Library Project in Visual Studio 2010 Express and put the code in a Class Module.Learned I needed this wonderful thing called an "Interface"... Made one of those:)I opened the project properties and went to "Assembly Information" and checked "Make COM Visible".I went to "Advanced Compile" options and targeted .Net 2.0 (it's very simple code).Removed all references expect for "System".Built the project (no warnings or errors) and copied the DLL out of the Bin folder into C:WindowsSystem32 Ran RegAsm /tlb. Everything seemes just fine.I popped open excel to run a quickie test and the TLB is available but I have two problems:
I can see both the class and the interface in the Object Browser/Intellisense.When I try to create an instance of either object (Set obj = New MyObj)I get the error:I can set a reference to the Object and the Intellisense can see it, I just get that error when I actually try to create the Object. Did I miss a step?
I have some VB.NET code that creates a TransactionScope instance:
LoggingUtility.LogDebug("UpdateCallTable", "SatComCallDataImporter", "About to associate call data with contracts")
Using ts = New TransactionScope()
LoggingUtility.LogDebug("UpdateCallTable", "SatComCallDataImporter", "Getting all unimported SatCom calls")
My application is throwing an exception on the call to the creation of a new TransactionScope, with "Object reference not set to an instance of an object.". The exception isn't thrown on my development machine or my test machine; only on the customers production machine, and I have no idea why. I've placed debug lines immediately before and after this line so I'm positive it is this line causing the problem.
A have used TransactionScopes throughout the application and this is the only place throwing the exception on the client machine."About to associate call data with contracts" gets written to the log and the next log entry is the "Object reference not set to an instance of an object".
Code works fine if I move it out of a transaction.I've been struggling with this for 4 days now and have got no closer.
I am having some real issues with this one. I have a class which contains two other objects...but I cannot seem to instantiate those sub objects. Here is the code for my class:
Code:
ption Explicit On
Public Class Boot
[code].....
I would like to know how will performance go when I instantiate multiple classes in one form.e.g
Public Class frmClass
Dim obja As New ClassA
Dim objb As New ClassB
[code]....
Beginner question. How come I can do this:
Public Class Form1
Private StudentsInMyRoom As New ArrayList
Public name As String
[code].....
#1 is C# Class Library, where I have my EF model defined (3.5 sp1) and some public methods.#2 is a VB winforms app.In the winforms app, I have referenced the C# library and added the connection string for the EF model. The problem I am having is that I have a form where the user selected a .txt file to import. On the VB side, I create a byte() from the file, then pass it to a public method cleverly called Process. In Process(), everything runs smoothly until I instantiate the EF model.
using (WorkersCompImportEntities context = new WorkersCompImportEntities()) { ....
Where I receive this error:
Could not load file or assembly 'System.Drawing, Version=1.0.3300.0,
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class
eg: dim classobj = xyz("CLASS_NAME") ' where classname is a valid class name
and dynamically raising a known method of that class on that newly created object or class reference.
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Whats the function for converting a string that contains a class, into a class?for example
Public Class Desk
Public GetVar=1
End Class
Dim T = "Desk"
Dim Furniture = New T
What do I have to do to T to make it into a class from a string?
I want to read a number of items from a file and then associate each of those items with a new button at run-time, so that when the user clicks one of the buttons I can display some information about that item.Can I use a LIST to manage these buttons and items? Can I create a new class and have each list item of that class, such as 'btnID', 'btnText', etc... ?
View 2 Repliescan someone please help me with a textbox? I have created a new class and require this textbox field within a sub in the new class but i get Error1 'TextBox1' is not declared. It may be inaccessible due to its protection level.I have tried MyClass.TextBox1 = Form1.TextBox1 but I get declaration expected.
View 23 RepliesSystem.Collections.Specialized contains StringDictionary
[url]...
What's difference with Strong Typed Dictionary in Generics?
I'm trying to get the ATM Class to Instantiate on the Form class.
[code]...
ISSUE = " 'ThisATM' is used before it has been assigned a value. A Null reference exception could result at runtime"
The Other problem i am having is with a class in the program called CardReader. What am i supposed to type to let the code below be able to "read" the read function on the Form1?
[code]...
Haven't coded in a while, and ran into a wall when setting up my program data structure
So I have something like this in a class file;
Public Class X
Public Stuff as Integer
Public Stuff1 as String
[Code].....
I want to structure my program this way, what's the best way to go about that?
I want to access multiple data types in the same array from within a class, as it should be a subset of my base class etc... and want to be able to change the size of the array
Or is this class array within class nesting a dead end?
I want to create a class that will "search" for something. Basically I load up the "search item" when the class is created and inside the class is logic to do the "search". The result of this logic will be more "searches" that I want to start. How can I have the logic in the class create another instance of the class itself?
View 3 RepliesI need to convert the following code, so that it exists as a created class "Payroll" that utilizes "Get" and "Set" elements. Unfortunately, I'm completely lost.
Public Class frmPayroll
Private Sub frmPayroll_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[code].....
I have two classes:
[Code]...
as I get an object not set error. Can someone give me the correct syntax?
If I create a DLL using VB 2010 express can it be used by previous versions of of .Net (3.5, 2.0)? Will the DLL use .Net 4.0 components, which is what I want. I don't see a way to force that to be the case.
View 1 RepliesI have a question regarding the some data which is being transfered from one form to my class. It's not going quite the way i'd like to , so I figured maybe there is someone who could help me.
This is my code in my class
Public Class DrawableTextBox
Inherits Drawable
Dim i_testString As Integer
Private s_InsertLabel As String
Private drawFont As Font
[Code]...
I've got a form with a textbox( form1) in which the text is being inserted and passed through a buttonclick (al via properties).As you can see I've placed several traces and in the property of the class my trace works fine , however if I look in my Draw function it is already gone.
I have database with class names listed in string field. I want to circle thru records and call certain class.
Eg.
Data table
ID ClassName
1 ClsCreateButton
2 ClsCreatePanel
After retriving this data in dataset(ds.tblClass) I want to do next:
Dim aClass as New ds.tblClass("ClassName")
Do something with aClass...
I'm going to show you an example of what i mean[code]...
View 3 RepliesI had a problem with CLR profiler. But it worked eventually and the results were outstanding. My app took 47 milliseconds to run before and after some adjustments CLR profiler runs in 6 miliseconds! This had to do with String values in a resource file which apparently takes a lot of time. So this got me thinking, isn't it more effective if you would declare 1 String at the top of your class and constantly change it throughout your code? Instead of creating a new String in a method when you need it.
Instead of using:
Dim text = "blalblalba"
You would do this everytime you needed a string:
text = "blalbla"
My question is... What exactly happens when you say text = ""? Does .net create a new String? It looks like you replace the text but what happens in the background? Would it be faster then declaring a new string?
Is there any way to set max string length in a class used in a VB.NET web service so it gets into the WSDL as a maxLength attribute?
View 1 Replieshow to set string content as a class instance name?Example. I have an INI-class with many instances like .Path, .Width, etc. Now, i'm reading my ini-file string by string wich hase been written by template:
[code...]
I would like to automate reading an assignment at ONCE. Like cutting the first word in line and setup it as my INI-class instance name.I know how to cut first word, but have no idea, how to set this string as instance name.
I'm trying to code a program but this error repeatedly shows up and I can't for the life of me figure it out EValue of type 'String' cannot be converted to 'System.Windows.Forms.TextBox'. It appears in relation to this code
[Code]...