Define A Property In Class Which Is An Array (of Doubles)?
Feb 6, 2012
I need to define a property in my class which is an array (of doubles).My original (bad) version is this:
Public Class Market
Property Correlations0 As Double
Property Correlations1 As Double
Property Correlations2 As Double
[code].....
This however doesn't work. I get an error already at design time: "Public Property Correlations as Double has no parameters and its return type cannot be indexed."What should I do with it? I also do not know in advance how large the array should be (the array size is determined at runtime based on other properties).
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Nov 29, 2011
best way to sort an array of doubles into a lowest to highest array of the same length.
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Jul 28, 2010
I have two classes, and for a property in one of the classes I'd like to be able to load it up with an array of the other class. However my attempt at accomplishing this results in a "Object reference not set to an instance of an object" error. I know it's a rookie mistake, but I'm stumpedssist?
My code is as follows:
Namespace Parking
Public Class garage
[code]......
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Oct 14, 2009
Stack Overflowers:I have been racking my brain trying to get an List(of T) type array to be the property of a class. I know there has to be a simple way of doing it and I can't find a good example on google. Everytime I create a class that I think will work I get the "Object reference not set to an instance of an object" error when I try to use it. My thinking now is that I cannot use it in the way I was hoping to. Here is my latest attempt:
Public Class Item
Private _itemno As String
Public Property ItemNo() As String
Get
[code]....
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Jun 23, 2011
I have a bunch of type Double variables in my program, say for example
Dim Area as Double = 0
Dim Perimeter as Double = 0
Somewhere in my program I want to calculate these values, so I define
Public Sub TheSquare(ByRef TheArea as Double, ByRef ThePerim as Double, ByVal TheSide as Double)
TheArea = TheSide^2
ThePerim = 4 * TheSide
End Sub
and somewhere in the program I'm collecting side lengths and calculating the area and perimeter; say
While True
S = GetSideValueFromSomewhere()
TheSquare(Area, Perimeter, S)
End
In my real program, I have, say, 20 quantities that I want to calculate. Obviously each one has a different equation. But in the end I want to output all 20 to a file, so to save typing, I create an array of the quantities, like this:
Dim TypingSaver() as Double = {Area, Perimeter}
so that I can dump values to file with a three-line for-loop instead of copying and pasting 20 variable names.
This does exactly what I want if Area and Perimeter were reference types like Objects. But since they are Doubles, TypingSaver contains only their values, not references to the actual variables. So after I use my TheSquare function the values of Area and Perimeter are correctly updated but TypingSaver just constains whatever the values of Area and Perimeter were when I declared the array.
how can I create an array of references to doubles in VB.NET?
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Sep 14, 2009
could anyone show me a code on how to transpose a two dimensional array of doubles (changing rows to columns and vice versa) ?
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Nov 3, 2009
I have created a class that contains a property array, but I cant use the setters and getters.
[Code]...
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Oct 1, 2008
I've been creating short test apps repeatedly to try to understand some of the concepts in VB.NET.For the most part it has been illuminating.I read Bucky's .NET knowlegebase tutorial on passing objects as parameters to newly created forms. He shows how to create a new class that inherits from the base form class and define a New() method with parameters Extending the concept I thought about doing the same thing with a form that was created at design-time (In this case Form2).
[Code]...
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Jan 5, 2010
I am trying to create a property of type string array (if this is possible).....and I seem to be lost.
I tried the following, but it says "String cannot be converted to '1-dimensional array of string'" at the return
Private _strZipList As String()
Public Property strZipList(ByVal i As Integer) As String()
Get
[Code].....
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Jan 20, 2012
Is there a way to define a class such that there can be only a single instance of that class?
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Aug 1, 2011
I want to know when I need to define a property in programming in general?,in every language
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Aug 20, 2009
I'm developing a class in which most of the properties need to be updatable, but also protected against being inadvertently updated. I've got some code that does this, but I'm not happy with it. What I have is:
[Code]...
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Mar 9, 2009
public partial class _Default : System.Web.UI.Page
{
private bool isEditMode = false;
protected void Button1_Click(object sender, EventArgs e)
[code]....
What is the VB code equivalent for the above C# code. Mainly how to define Property (IsInEditMode) and Global variable (isEditMode) in ASP.NET?
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Oct 15, 2009
I need to do something like this Class A End Class Class B Inherit A End Class A=B If i try i get an exception! that i can not cast B in A. How can I overcome this problem? I need to define 2 classes B identical to A but as a distinct class What I need is to be able to cast one class to the other like A=B or B=A I tried with directcast but i got the exception what can I do
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May 25, 2011
below is my code to use binarywriter it work fine on class form1 level
[code]...
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Jul 28, 2010
Interface Iinterface
Sub myMethod()
End Interface
class myCls implements Iinterface
End Class
i did this and i wanted to define the myMethod() within the class myCls but i am getting an error in this line:
class myCls implements Iinterface
error:end of statement required
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Apr 17, 2010
I would like to define a class as something like a constant, and use the class directly rather than having to always create an instance. Is this possible? I've tried a handful of combinations of syntax, but nothing I've tried lets me do what I'm after. To give an idea of what I'm after:
[Code]...
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Feb 28, 2010
How to define array in vb2005? (Actually, I am making a game, whcih have to find out a pair of same pictures. I want to randomize 8 pictures, but it will randomize some pictures which is the same. Therefore, I need to use array.
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Apr 29, 2010
I'm developing a software that handles very specific regional standards. In one part of the country they have different standards for entering this data than they do in other parts of the country. In fact there are hundreds or thousands of possible configurations that would be best in various regions.
The solution I've come up with is to write a program that can load different control configurations with the supporting code to its main form at runtime. I do not know how to accomplish this. Would I use visual inheritance at runtime? Would I use a plugin system? I just need to potentially allow a power user to design thier own interface or to modify an existing interface to better suit thier needs.
Edit: Is there a way to define the base class of a form at runtime? Could I create user controls in a plugin and pass them in to the host program?
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Mar 2, 2009
I'm trying to recreated some Excel code and an struggling with defining data types for use in Arrays.
Excel Code
Type Bags
feed_Bags As Long
drop_Bags As Long
level3_Bags As Long
mcs_Bags As Long
[code]....
How can I re-created this in VBA
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Jul 12, 2011
I was just practicing some coding and noticed that I was able to use class instead of Module in VB .NET. So I replaced my module to class and I got this error message:No accessible 'Main' method with an appropriate signature was found in 'practicevb'.practicevb
I made sure that the startup object was set correctly in Properties > Application > Startup Objects.The error message disappears if I change it back to Module but I would like to keep it class since the other parts of my code I changed to class and didn't return and error messages.
Class Atic
Sub Main()
Console.WriteLine("Hello, this proram will calcaulate the quadratic forumla ax^2 + bx + c")
Dim Quads As New Quads
[code]....
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Oct 21, 2009
1 - Need to create a kind of composite property, like the font property, that it's showed with a plus sign to expand. For example i need to define a new pen, i need to define the color and the width... 2 - I need to define the color for one brush, but if i create a property of the type brush in the PropertyGrid it appears like "System.Drawing.SolidBrush"
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Mar 22, 2011
Is there a way to define an array inside of the sub call parentheses?
Private Sub sub_name(byval sString, arrString)
sub_name("Some Text", array.{"","",""})
What I've been doing is passing a string and using a split on it to break it into an array in the Sub/Function, but I was wondering if there was a way to make the array inside the parentheses. I've looked through Google, but I'm guessing I'm not asking the right questions or it's not possible.
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Apr 30, 2012
I have a form that contain 30 image (load by array) and when one of the image clicked, the background of my frmMain should change to the image clicked. The program has no problem by launching the code below :
Private Sub PictureBox1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles picWallpaper1.Click
frmMain.BackgroundImage = picWallpaper1.Image
End Sub
Private Sub PictureBox2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles picWallpaper2.Click
[Code] .....
But this way is not effective if I want to increase more image up to 50,60 in future the program will loaded with these code.
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Feb 12, 2010
Structure Tinnings
Dim bowler As String
Dim ball() As tballs
End Structure
[code].....
how can i now define the length of the array ball() in Tinnings structure to 6, (its a cricket program, with 6 runs in an over).
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Mar 12, 2011
Under Visual Basic 2010, I am trying to define a specific instance of a static method that was created as a Java class. I have a vendor supplied dll added in as a reference.[code]...
But, I can't seem to define a specific instance of this method. Using "IntegrationMethod.getIntegrationMode()"always returns a value of zero.
There doesn't appear to be any way to "setIntegrationMode" to a specific value.
The documentatoin for this Class as provided by the vendor are shown below.
When I asked the vendor for assistance, their response was: "
Our javadocs for the IntegrationMethod class show that we provide three predefined instances of the IntegrationMethod class[code]...
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Oct 27, 2009
I am having a problem with a and OOP class i made that contains a sub that creates random integers.
Problem is if i define two instances of this class and configure them(name in this case) then they both display different names but the random integers are ALWAY the same. in this case having the integers the same kinda kills the idea of the program.
Is it possible that the random part only every works for one class, but if .NET is fully OOP then this should not be possible... right?
Some of my Code (broken down to something smaller) i will display for obvious reasons.
Code:
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Jun 1, 2012
I have a very simple class that holds a few public properties - ID, Text, Colour, etc. and a Boolean called 'SelectedItem'. Just like the Checked property on RadioButtons, only one item can have its SelectedItem property set to True within a particular group. Note: there will be several separate groups (lists), each allowed to have only one item with SelectedItem = True.
My first thought was that I would probably just have to handle everything outside of the class, setting SelectedItem to False for every other item in a particular list when another item was selected. But that seems rather inelegant to me. So I've been trying to think of how this might be done within the class. For example: could I perhaps have a private string property called say "GroupName" - set in the New sub when adding a new instance of the class - and then use a private shared method to set every item's SelectedItem property to False, provided the item has the same GroupName as the newly selected item? I would have a go at doing this but I have no idea how to enumerate every instance of a class from within that class, or whether that's even possible. Is it? Or is there another (better) way to achieve my goal? Here is a cut-down version of what I've got so far:
Public Class ResourceItem
Public ID As Integer
Public Text As String[code]....
As can be seen: instead of instantiating a new ResourceItem and passing that as an argument to the manager's Add procedure, I'm simply passing the details of the new item and the procedure is creating the item from those. I don't know whether this is a good or bad idea - please advise - but I've done it because I couldn't figure out how to make the SelectedItem property only writeable by the manager, so I wanted to avoid having directly accessible objects that could have their SelectedItem property set to True without it deselecting all the other items in the same group. Of course that still leaves the possibility of setting a variable to one of the manager's list items and setting it from there, so I would still like to know how I could prevent that, if possible.
UPDATE: I didn't use the code above in the end, deciding instead to go with Cyborgx37's solution - which seems to work perfectly well for me despite the warnings about best practice. I also realised I would need to use the same class in another scenario where multiple items could be selected, so it was easy to add a Boolean property to the manager to enable that.
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Aug 13, 2009
I have the following code:
Public Class MyColorsClass
'Constructors
Public Sub New()
'Empty Constructor
[code]....
However, if the empty constructor was called to instatiate this class then the colortype is not yet set. Therefore, if one accesses the 'IsColorCool' property it will always return 'False'. Now for the sake of this example, I must keep the empty constructor as part of the class.Now I could add some code in the 'IsPropertyCool' to check and see if a ColorType has been defined, and throw an exception if it has not been set, but I don't really want to do that.I also could always move the logic OUT of the property and into a method on the class called 'DefineIfColorIsCool' or something, and make the owness on the caller to make sure the method was called if they want to use the property 'IsColorCool'?
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Apr 7, 2011
Supose a base class
Public Class airplane
Private var_num_seats As Integer
Private var_num_engines As Integer
[code]....
Obviously, I don't wish that the class Glider has the method "start_engines" neither the property "num_engines". Otherwise, other child classes may have. How can I supress these property and method in child class, not just ignoring (if I can)?
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