Derive A Class From Double?
Mar 10, 2009
It seems like SO often I need to attach a "valid" flag to a standard type. For example - I have a function called "CalculateLunchTime" that I pass a vector of times. If the vector has 0 elements, they did not take a lunch, so the duration is 0 minutes. If the vector has 2 elements, subtract them and that is the lunch duration. If the vector has one element, it doesn't make sense to calculate a duration, but I don't want to return 0 because that was for the first case. In this case the valid range is >0, so of course I could return -1 or something, but it really bothers me having these magic numbers running around. I would really want to do something like
public function LunchTime(byval Times as list(of Date)) as ValidDouble
dim lunch as ValidDouble
if Times.count == 2
[Code]....
Of course I could make a struct with a double and a bool, but I have really never seen anyone else do that so I feel like it could be a bad idea (why?). It would seem a little nicer if I could derive ValidDouble from double.
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Aug 15, 2011
For greater accuracy I should use a Decimal instead of a Double ( so I've been told ). Why then have Microsoft chosen to use DOUBLE for most of the functions that return a floating point value in the Math Class?
[Code]....
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Apr 30, 2012
I've got an array that contains the following:
a;b;c;d
but it can also be that this array contains this:
a;b;c;d;(0,0,1000,1000)#(1000,1000,2000,0)
So first I do a split on ";"
If Ubound(array)= 4 then I now the second case with coordinates is valid... in this case 2 sets of 4 coordinates
How do I derive them from array(4) as xstart0,ystart0,xend0,yend0 and xstart1,ystart1,xend1,yend1 ???
Do I need to do another split on "#" first and then on the "," ?
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Jun 25, 2009
I need to generate the IV and the KEY for an AES cryptography. I want to use the password and i am asking if it is safe to use the same password to get the Key and the IV?
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Oct 7, 2010
As part of my exception handling, particularly in class modules, I like to pass back the offending module name and the procedure in which the exception ocurred. I can get to the module name by using;
Me.ToString
and that returns AppName.ModuleName Is there a way to programatically get to the function or sub name. For now, I have to hard type it like this;
[code]....
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Nov 26, 2009
ok basically i've got a delegate ByVal function_to_execute As dele0 but instead of invoking it, i wish to add it to an eventhandler
Public Sub test(ByVal function_to_execute As d0)
Dim t As Timer = New Timer()
AddHandler t.Tick, AddressOf function_to_execute.address
[code].....
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Jan 27, 2011
I have a situation where I am handling both single & double mouse click events on a form. In both cases something has to be loaded, however when a double click occurs, I do not wish to execute the code attached to the single click event.Is there a way to intercept the mouse click's and check if double or single and then execute the right event appropriately?
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Nov 17, 2010
I have a htpc project that I am working on. The main program loads dll plugins which are basically other win forms. On each of these forms, including the main program, I use a picturebox (a double buffered picturebox) for the background image and then draw everything on it by hand. Whenever I load the form from the dll and show it, I get a weird flicker. It looks like it is the previously used double buffer. Is there any way to clear the background double buffer before the flicker? Or am I going in the wrong direction?
Here's a couple of videos of the problem:
[url]
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Notice the black screen with the white lines on it or the flash of the desktop after I click "Movies." How do I get rid of that?
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Apr 4, 2009
In vb.net, im using objWriter.Write("playerA= "x"")as you can see im using double quotes inside double quotes, how do i skip it so the error doesnt show up?in php you make an "" to skip the string like ("playerA = "x" ")
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Aug 11, 2010
When i use VB6 i get the following outputs
961.605 * 100 = 96161
936.495 * 100 = 93650
929.295 * 100 = 92929
NOW..... When i do the above in vb.net 2005 i get the following
961.605 * 100 = 96160
936.495 * 100 = 93650
929.295 * 100 = 92930
How can i get the same output as the VB results. And i have tired it ! Type conversions, math functions, everything i can think of to get the same VB6 output !
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Aug 11, 2010
When i use VB6 i get the following outputs
[Code]...
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Oct 27, 2009
I've asked this question before, and so have many before me, i have done extensive research on the topic and stil no help. Maybe this is some kind of secret info. shared only amongst top programmers. Bt how do you really, trully double buffer a form, aside from setting "Double Bufferd" to true, which doesn't work in most cases, I want to know how do companies lyk Microsoft and Symantec, prevent flashes on big applications such Word and Norton.
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Feb 23, 2010
If I try to display a command line argument that has double quotes around, the double quotes are always stripped off. How can I avoid this?
for example, the argument is "c:xx.txt" and this displays c:xx.txt instead Console.WriteLine((My.Application.CommandLineArgs(4)))
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Mar 25, 2009
I have a CSV file where the values are in double quotes and seperated by a comma. I'm getting incorrect data if I try to seperate the string with my Split function. How do I do it?
Example:[code...]
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Apr 12, 2011
I've been just making random programs trying to get the hang of the new language this time I was making a leap frog game where it switches back and forth beetween frogs every time a button is pressed. It also checks if the frog can land in the text box above the button pressed, if there is another frog there a message box will pop up saying sorry space is filled other wise the frog should land there.
[code]...
The error message says "Conversion from string "frog1" to type 'Double' is not valid." I understand what a double is but I've tried And If and that causes a bunch of errors.My Question is whats wrong with this cod and how can I make a double if statement???PS I did try to make an array to shorten this but thats in a different fourm will post URL later
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Dec 16, 2009
If Class X is within the scope of Class Y, is X a subclass of Y?If Class A is a sub Class of B, then is Class B considered a super class of A?if Class C inherits Class D is Class D a superclass or parent of Class C?if Class E extends Class F then we can consider Class E a child of F?if Class G inherits Class H and is within the scope of Class I then who is the parent of Class G? Classes that inherits Class J and classes that are within Class J are all sub classes of Class J?
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Apr 15, 2010
I have put this code in the global form Inherits System.Windows.Forms.Form. And then in the form that will inherit this from the global Inherits MenuStrip. "MenuStrip" is what the global form is called. But keep getting this error: Error1Base class 'MenuStrip' specified for class 'Lesson2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types.
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Jul 22, 2011
I have a class (see below)
Imports Microsoft.VisualBasic
Imports System.Data.SqlClient
Public Class ClientProfile
#Region "Variables"
[CODE]...
It is in the file ClientProfile I have placed in both App_Code and also App_Code/Models
In my code behind I have the following
[CODE]...
The last word, "ClientProfile" has the scary squiggly red line below it. It is not recognizing my class.Even the Intellisense is not picking up te class. Do I have to register the class file in any way?
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Sep 11, 2009
Dim a as Type=GetType(className) would gimme the type. But I have only the name of the class as string. I want something like GetType("class1") which would return the type.
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May 15, 2009
I can't make difference between public class and private class and friend and protected friend class.
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Jan 21, 2010
I can do this without problem.
Class A
End Class
Class B : Inherit A
End Class
Dim Obj1 As A = New B
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Aug 9, 2011
so I used to mess around with C#, just a little. And someone had helped me make a class for Visual C# that was supposed to do the math parts for "internal structure" - which the program used for a part of its calculations and screen... Basically there were 2 options. Endo-Steel and Standard. The user would use a updownbox to determine weight of the machine and then internal structure was a % of that total. If it was standard then it was 10% of the overall weight, if it was Endo-Steel then it was 50% of standard (so 5% of total weight) rounded to next 0.5 (so .25 was .5, 1.25 was 1.5, 1.75 was 2.0, etc). I have the code for the C# class file for it, but want to make it in VB.
[Code]...
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Mar 1, 2010
I need to create unit testing project for my current website. The currentw ebsite si written in VB. All unit testing examples are using interface to create mock object. My current VB class does not implment any interface. Can I add interface and implement it to my current class and functions without affecting or changing codes to any pages in my website that call the functions? For examples my current class is like:
[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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May 13, 2011
Example:
Two files - TestClass.vb, myForm.vb
TestClass.vb looks as follows:
Imports System.Threading
Public Class TestClass
Private myClassThread As New Thread(AddressOf StartMyClassThread)
[code]....
The result:Application runs, no errors or exceptions.Displayed is the listbox and the Start button.I press the start button and a msgbox says "Not Invoked" as expected and upon clicking OK to that msgbox "Start Button Pressed" is added to the Output listbox control.Immediately following that the msgbox pops up again and says "Not Invoked". I was expecting "Invoked" as a separate thread is trying to use the Output listbox control.Of course this results in the Output.Items.Add being attempted which results in no visible result as the thread is not allowed to directly update the UI control.
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Aug 18, 2009
I have some classes, BsfciFile and StudyFlashCard. Bsfci is the extension to which I save my set of flashcards in an INI format. I am currently working to transform my code from using Windows API calls to access the INI to using a IniFile class that I found on the internet. I would like the BsfciFile to have a Array of StudyFlashCard objects, but I would like the StudyFlashCard class to use the IniFile class object contained in the BsfciFile class. I can pass the IniFile from the BsfciFile class to the constructor for the StudyFlashCard class, but I want it to modify the same IniFile as the BsfciFile class has later on.
[Code]...
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Nov 18, 2010
I have a class that is stored after serialization and compression.Is there any event built in the class that is fired automatically when a class is deserialized and ready to be used??
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Apr 22, 2012
Base class has one field to hold numeric balance value. With 2 methods that accept arguments for adding and subtracting the new input calculating new balance. Sub class has four fields dates, transaction, memo and amount.I have a deposit form, and withdraw form. Each time one transaction is entered it creates an object with sub class fields, then adds to the account collection. My problem is not understanding how to call the deposit/withdraw method and pass the current transaction amount back to the base class to alculate the new balance. Does anyone have any links to information/tutorials on how to perform something like this? As you can see with my code I have tried various different approaches without any success.
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May 8, 2012
Create a class named Service. Inside the Service class, declare a class variable named Started. The datatype of this variable is Boolean.Public Class Service Dim started as Boolean End Class Create a class named Server. Inside the Server class, declare a dynamic array that can contain elements of the type Service.(Note: For convenience, both the array and the variable Started can be accessible from a client program that creates an instance of Server and Service respectively)
Create a constructor for the Service class. When the constructor is executed, it will set the value of the class variable Started to True. Create two new classes: WebServer and DatabaseEngine. Both of these classes inherit from the class Service. Inside the Service class, declare a Sub procedure (method) named Terminate. This method should display the following text Service stopping in a message box when executed.This method can be overridden in classes that inherit from Service class.
Inside both the WebServer and DatabaseEngine class, override the method Terminate inherited from their base class Service. Both methods should first call the base class Terminate method. The messages Web server stopping and Database engine stopping should also be displayed in a message box when the Terminate method for the WebServer and DatabaseEngine are called respectively. These messages should only be displayed if the Started variable inherited from their base class is not equal to False.
Inside the Server class, declare a method named Shutdown. This method does not return any value. When executed, it will call the Terminate method for each of the Service instances (if any) in the arrServices
array. You should call the Terminate method within a For Each loop that loops through the elements of the arrServices array.
In the Sub Main method, create an instance of the class Server. Set the size of the arrServices array in
your Server instance to contain 2 elements. Create first a WebServer instance and then a DatabaseEngine
instance into this array. Call the Shutdown method from your Server instance.
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Jun 7, 2012
I want to created a nested class that can only be visible to and instantiated from the parent class.But I also want to be able to use an instance of the nested class through a public variable of the parent class.I tried making the nested class private, or making the nested class' constructor private, but it won't compile.Is it possible to do this in .NET?
[Code]...
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