What is an elegant way to create and initialise instances of a class that has several readonly properties? Passing all values in a constructor would not be very convenient.
The purpose is that instances are immutable after initialisation. However if the constructor is not used for initialising all the property values, then how can the readonly properties be changed from another class?
I'm trying to elaberate on some basic examples of .Net programming in using VB. The basic example of creating a new instance of Form1 is:
Dim x as New Form1
x.Show
I've added some OptionButtons to set the StartPosition of the Next Instance of Form1 as well as some Labels that display the Top, Left, Width and Height properties when the new instance of Form1 is Shown.
This is the code I'm using.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim x As New Form1
If Me.RadioButton1.Checked = True Then
x.Top = 0
x.Left = 0
[Code] ......
info on creating instances of my own class at runtime. Simple project for family recipes but would like the option to add new recipes with new instances of my own food Item class at runtime. Creating my own class,no problem. Storing the data in an XML file, OK on that as well. My issue is creating new instances of different food item class as I use this program over time
View 13 RepliesI'm trying to figure out a way to sort the entries of a listbox... but in a different way instead of the obvious one (sorted property). First of all, I need to explain how the items are populated at first:
[Code]...
I have a class structure and am attempting to create an array of object instances from the class some instances are parents and some are children Code snippets,
Parent Class object
Option Strict On
Option Explicit On
Public Class cTransportItem
[code]....
I am using a PropertyGrid control to edit my class properties and I am trying to set certain properties read-only depending on other property settings.This is the code of my class:
Imports System.ComponentModel
Imports System.Reflection
Public Class PropertyClass[code].....
This is the code I am using to edit the values:
Dim c As New PropertyClass
PropertyGrid1.SelectedObject = c
The problem is that when I set SomeProperty to True, nothing happens and when I then set it to False again it sets all properties Read-Only.
We use a common web.config file to store all of our database connection strings.
I would like to have a way to read in all of them, somehow create a property or type so that they become dynamically available.
So when I want to create a new sql connection my my class can show the connections strings available.
Dim myconn as new MySqlOps.Connection(MySqlOps.ConnectionString)
so when the user types MySqlOps.ConnectionString. it will give a list of the connection strings read in from the config file.
Not sure how to approach making the connectionstrings available like above.
I was hoping to make a PersonViewModel class from an EF Person class, so I can expose more bindable properties.
Public Class PersonViewModel
Inherits Person
Public Sub New(ByVal P as Person)
[code].....
Let's have three classes;
Line
PoliLine
SuperPoliLine
[code]...
I'm faced with a couple of problems in VB.net: I have a series of objects, which properties I'm displaying in a grid for the user to edit. My first problem is: how do I get a list of all the properties of an object? Is it even possible? The datagrid control that I'm using accepts string values with the name of the property as parameters, but inserting them manually would be a real problem, because there are a LOT of them. So: is there a way to get a list of strings with the name of each property of an object?
If that's possible, here comes the second question: Now, of course, since users are editing the properties, I'm not interested in showing ReadOnly properties which they cannot edit. Hence my secodn problem: is there a way to check if a property is readonly at runtime?
I have a bunch of private variables I've typed out and I want to put all of my corresponding Public ReadOnly Properties in a bunch below them.Is there some way of copying ten lines of
Private _myVar As String
and pasting in ten sets of
Public Readonly Property MyVar As String
Get
Return _myVar[code]....
I'm currently copying the whole bunch of variable declarations, Find+Replacing Private _ into Public ReadOnly Property then going line-by-line expanding the definitions and writing return statements.how to avoid all this nonsense in the future, as I'm developing on a virtual terminal server, and the input lag on my little copy/paste/type operations on the code is driving me up the wall.
I'm designing an application for a class where the user inputs three values and the program tells them whether it is a right triangle, equilateral triangle, or neither.I'm trying to figure out how to test for a right/equilateral triangle in my get accessor.... Here is the code so far for the class:[code]......
View 1 RepliesI'm working on rewriting something in VB that was previously in C# and while I was doing so, I came across a "dilemna." I can have a ReadOnly Property:
Public ReadOnly Property MaximumIndenture()
Get
Try
'If the connection is closed, open it.'
[code]....
They both essentially do the same thing, but I'm not sure which would be more accepted in the community.
I have created a class for a Sports Facility. A facility has a Name, Status, Notes, etc as members of the class. This works well, I can create a new instance of an exisitng Sports Facility from the database, create a new instance, etc. All working well.What I am stuck on is accessing a list of Sports Facilities. I know I can create a new list by doing
Dim List As New List(Of Facility)
For Each fRow As DataRow In ds.Tables("Facilities").Rows
List.Add(New Facility(fRow.Item("FacilityID"))
Next
I'm trying to create 3 instances of the the Workshop selector form for the 3 individuals that I have inthe listbox to appear when I first run the program.
View 4 RepliesI have a form (form1) and I havea button on form1 (button1) that will start a second form (form2).How can I make it create multiple instances of form2 when button1 is clicked?i tried a process module that the studio comes as standard but it does not allow me to start multiple instances...how can i do this?
View 14 Repliesthis is probably something I should know, but I'm puzzled by this.I'm trying to create some objects and being able to access and modify these globally. I tried to create a Public Module and declare a few objects in this.I am able to access these from another sub, but I get an exception error when after building and runing the process and trying to modify these object. The same thing happens if I declare the object in the Public Class Form1. For example like this:
Public Class Form1
Public appWord = New Microsoft.Office.Interop.Word.Application
Public wordDoc as Microsoft.Office.Interop.Word.Document
[code]....
I am using MEF to compose a number of components at run time but when I use a metadata attribute it double the number of parts in the collection.
When checking the container.ComposeParts I can see that the dll containing the 11 implementation of IStages is loaded once and only the 11 part required appear but when it resolves the Private Property Stages As IEnumerable(Of Lazy(Of IStages, IStagesMetadata)) the number of instances is doubled to 22. Looping through the collections I can see that they are duplicated by the ID in the metadata.[code]...
I am trying to create a subroutine that creates multiple instances of a specific form.
Here is my code:Public Sub NewFormInstance(ByVal FormName As Form)
Dim FormInstance As New FormName
FormName.Show()
End Sub
Is it possible to create instances of controls on a form ? Of course I mean visually , not just by code. After all, these languages define themselves as "Visual" so they should provide that possibility. It is important for the instances to be visible during design time because otherwise we could only guess where those controls might "land". Nevertheless , I have the feeling this is not possible in VB .NET but still I thought I should ask first ...
View 11 RepliesI have been trying to create good multithreading programs and it is not working well considering the use of global variables, local variables etc and thread safe controls. I have not found a good way of doing it since it seemed to be not as efficient as just running it on a single thread.
The program accesses facebook and twitter api, parses etc. and I am wondering if I can just create new tasks and map the program project file and fire new instances of the project. Someone this using the taskfactory in 2010 but I thought this was just the same as the threadpool. on this: create windows services and set them to run on task scheduler??
I'm creating a twitter account manager using the Twitter API. I have multiple accounts, over 10 of them. I want to automate all 10 of these accounts to do certain things, now the way I started to code the program was so that it would accommodate only one account, and all the codes worked perfectly and were managed by individual timers for individual processes that I wanted done. i could tweet between certain intervals, follow people who tweet certain things without me being on top of it.
Now the problem is that I've been trying to create new instances of subs that I've already created so that I dont have to create 10 new subs with the exact same procedures. I'm pretty sure it's impossible to create copies of subs dynamically or within a loop but it didn't stop me from trying. So question is how can I edit a program that was designed to accommodate and automate only one account, to potentially accommodate over a 100? I don't need codes or anything I need ideas so I can try them, but right now I'm completely blank.
I have the following problem. (VB.Net 2008)I have created a class (myFirstClass). In this class there are a lot of calculations being made wich gets fired by events in that same class.Now i want that same class to be able to fire more instances of itself. However i noticed that each time i fire an event from a Sub the program waits till the event is finished before going to the next line of code. This is a problem since i want the event wich fires a new instance of the class to fire it and forget about it.
View 7 RepliesHow does one implement something as Public ReadOnly Property within a class.
CODE:
I have created a class called clsLogIn [code]Now I am on a different form, frmSchedule, and I want to get the ProviderNum property from clsLogin into a text box.
View 10 Replies[Code]...
Is there an explanation for this limitation? I mean, it's still in the constructor for the object, and the base class constructor is still executed first.
Is there some interface I can implement to allow basic comparisons and math to happen as it would an integer?
For example, let's say I have the following class:
Public Class Something
Public SomeBigNumber as UInt64
End Class
I would like to do something like this:
Dim SomethingA, SomethingB, SomethingC as New Something
....
If (SomethingA-SomethingB) > SomethingC Then
'Do stuff
End If
I was hoping to be able to implement some interface (if that is even the right term for it) that would return the UInt64 contained in the class for comparison and math, if possible.
I have a form whose purpose is to let the user to load map files.The form may manage a variable classes of maps, and each class have his own UserControl.To make it more user friendly, I added to each UserControl (different instances of the same class), a little map, showing a small picture of the map, and some data, as bound coordinates.
The problem is, that it looks really ugly. The maps are so big, compared with the rest of the UserControl (who contains just a button and a textbox to search for files).I wish to fix it, but I din not see an elegant way to include the pictures and info.I attach a form screen capture with two UserControl.I would like to get some tips for more experienced users. There are some guidelines?
I have a sub that runs on a button click which I want to create a new instance of a custom class and add it to a list of already created instances of this class. I want the result to be a List Of collection of all of my class instances.
My problem is that each time I run the sub, it simply 'overwrites' the first instance of the class and adds a copy of it to the list instead of writing a new instance. My code is along these lines
dim objFixture as new clsFixture
For n As Integer = 1 To intNoOfChannels
objFixture.SetChannelAddress(n, intCurrentChannelTotal + 1)
intCurrentChannelTotal += 1
next
lstFixtures.Add(objFixture)
I created a program a while back, in the traditional VB.NET way by drawing a bunch of forms. I have started playing around with creating the forms at runtime using classes. I have a placeholder form called frmStartup which merely calls the CreateLogin() sub from the CreateFormClass. The CreateLogin() sub creates a new blank form, then calls the grpbxLogin(), btnSave() and btnExit() subs from the FormElementClass which adds all the buttons and textboxes to the form. Within the FormElementClass, I have associated btnSave and btnExit with event handlers. These even handlers call subs from the DataProcessingClass. The event handler for Exit works just fine.I am having a problem with the Save event handler. Precisely, I don't know how to pass either the username or password from the Login form to the btnLogin_Click() sub in the DataProcessingForm. I have tried using Me. and frmLogin., but the program doesn't see either of those. If the Login form is an instance that is disposed of once another Sub is called, then it won't exist later on to call from. I have tried declaring variables and passing those along to btnLogin_Click, but no matter where I put it, the program doesn't see txtbxUsername.Text or txtbxPassword.Text. Not even from within FormElementsClass, which is were the boxes are created.Any ideas on how to pass variables in this case? I am not even sure what you would call this such as passing between classes, or passing between instances.[code]
View 9 Replies