Initialize A New Instance Of A Class, But Pass It To Other Forms Too For A Wizard Based App?
Dec 20, 2011
As an ameture developer, I've never really used classes. However, I've been reading about using classes and automatic properties. I have therefore created a class which looks similar to this:
Public Class Quote
Property QuoteNum as integer
Property AccNum as String
Property Price as Decimal
End Class
The stumbling part for me comes in the way of letting form2 know which class form1 has initialized. There are in this example 3 forms to this wizard. If someone starts another wizard whilst half way through the first wizard we need to keep the variables seperate hence using the class. I think I'm along the right track, but maybe confusing myself a little.
[Code]...
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Jan 13, 2011
I have an application that reads another processes memory.I initially had multiple scanning threads for the various areas I needed to read.This was processor intensive so I decided to go with the observer pattern.All was well except that I am having a weird behavior.Here is what is happening.I have 2 radars (overlay and mapped)Both have a watcher class that attaches to the memory scanner and is notified on a new list of mobs.so I open radar 1 (mapped) it attaches it's watcher to the scanner and waits for mob list update notifications
Open radar 2 (overlay). same thing happens and another watcher is attached.all is well and good so far.Now there are properies on the mobs in the list, one of which is IsFilteredOut.This property is set in the radar code after it receives the list. Now the weird behavior is that no matter what I do, the second radar to be opened changes all the properties of the mobs in the list of both radars.It is as if I am passing the list by ref, but I am not.I actually create a new instance of the moblist class every time I pass the list.Here is the notify code. As you can see I create a new instance of the moblist class each pass.
Private Sub NotifyMobListUpdated(ByVal Mobs As List(Of MobData))
If Mobs IsNot Nothing Then
For Each w As Watcher In _watchers[code].....
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May 26, 2009
You know how everyone says "C++ is like C with classes"?How similar is it to .NET classes? instance a class, based on other classes, add new properties, override existing properties, etc?Are the variables strongly-typed and declared before they are used? Or is it a Duck-Typing language like Python?
Also, does it have its own Garbage Collector that disposes of objects when the pointer exits their scope,or do you have to manually clear and get rid of them when you finish with them? What's the difference between native C++, and the "managed C++" in Visual Studio? Because I'd prefer to use native code if its not too much harder. for the sake of all that is good and holy, don't use ACCESS, EXCEL, or a TEXT FILE as a database. If you want your program to use a "local database", without any of the hassle of setting up a MS SQL or MySQL server, just click this link: >>> SQLite <<< Seriously. This is for your own good.
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Sep 3, 2010
how to pass string between forms instance throw the instance it self not any other form
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Oct 20, 2010
The "named pipe" seems rediculous to pass data between processes (exe's). Is it possible to run a single instance of a VB.NET Class Libary (dll) such that two programs can access the same memory resident dll, thereby passing data via functions and or subs?When I try to make the class library as single instance, the "Enable Application Framework" is greyed out, and thus the option to "Make Application Single Instance" is also greyed out.When I try to call the dll from two processes, I simply just create two instances, so storing data in a module doesn't work
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Aug 29, 2011
I don't know how to do this and I've googled this to death.
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Jun 25, 2011
i have a class called car and within that class i have a few vairables
Public Class car
Public Property Name As String
Public Property ID As Byte
[Code].....
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Aug 11, 2011
The following code:
CodeVariableDeclarationStatement variableDeclaration = new CodeVariableDeclarationStatement(
// Type of the variable to declare.
typeof(string),
// Name of the variable to declare.
"TestString");
Produces the following VB.Net Statement:
Dim TestString As String
What change would I need to make for it to look like this:
Dim TestString As New StringBuilder()
I'm interested in how to get that NEW keyword to appear.
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May 8, 2012
I have created a class (pasted below in case I did something wrong) for which I want to create an instance that is usable across forms/modules. I can create an instance of the class in a single form/module no problem via DIM User as New User but how do I go about create a public instance accessible from all parts of my program?
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Jan 5, 2011
After debugging a particularly tricky issue in VB.NET involving the order in which instance variables are initialized, I discovered that there is a breaking discrepancy between the behavior that I expected from C# and the actual behavior in VB.NET.Nota bene: This question concerns a slight discrepancy in the behaviors of VB.NET and C#. If you're a language bigot that is unable to provide an answer other than "that's why you should use C#, noob", there is nothing for you to see here; kindly move along.Specifically, I expected the behavior outlined by the C# Language Specification (emphasis added):
When an instance constructor has no constructor initializer, or it has a constructor initializer of the form base(...), that constructor implicitly performs the initializations specified by the variable-initializers of the instance fields declared in its class. This corresponds to a sequence of assignments that are executed immediately upon entry to the constructor and before the implicit invocation of the direct base class constructor. The variable initializers are executed in the textual order in which they appear in the class declaration.
Contrast that with the portion of the VB.NET Language Specification concerning Instance Constructors, which says (emphasis added): When a constructor's first statement is of the form MyBase.New(...), the constructor implicitly performs the initializations specified by the variable initializers of the instance variables declared in the type. This corresponds to a sequence of assignments that are executed immediately after invoking the direct base type constructor. Such ordering ensures that all base instance variables are initialized by their variable initializers before any statements that have access to the instance are executed.
The discrepancy here is immediately obvious. C# initializes class-level variables before calling the base constructor. VB.NET does exactly the reverse, apparently preferring to call the base constructor before setting the values of instance fields.If you want to see some code, this related question provides a more concrete example of the divergent behavior. Unfortunately, it does not provide any hints as to how one might coerce VB.NET into following the model established by C#.
I'm less interested in why the designers of the two languages chose such divergent approaches than I am in possible workarounds for the problem. Ultimately, my question is as follows: Is there any way that I can write or structure my code in VB.NET to force instance variables to be initialized before the base type's constructor is called, as is the standard behavior in C#?
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Jan 21, 2010
How to create a data forms with the data forms wizard in VB 2005
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Aug 23, 2011
I was looking on the interweb to see if there were any good examples on how to initialize shared members within a class while still initializing instance variables.[code]How do I initialize both instance and shared members without re-initializing the shared members every time an object is created from a class?
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Jan 27, 2011
I have classes similar the following:
[Code]...
I want the Name property of the Dings class to be initialised at first, I know, I could also create the foo-object (as member of dings) later in the constructor. But I want to have it this way, because in the end there are very much singleton objects instantiated in the Dings-class that I want to be created in only one line.
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Dec 8, 2010
I was looking on the interweb to see if there were any good examples on how to initialize shared members within a class while still initializing instance variables. I did find an expression that might fit to the answer:
[code]...
How do I initialize both instance and shared members without re-initializing the shared members every time an object is created from a class? Thanks!
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Feb 15, 2012
I am building a code behind page that has a public property (MyDTOItem) which is essentially a DTO object (dtDTOItem) Note: In my code the Get and Set are actually real code (I stripped it for the example).The problem I am having is in the Page_Load event. When I set the .Member1 property of the DTO object the Get code runs and not the Set and therefore the DTO ibject property .Member1 never gets assigned. I figured out that if I add code (MyDTOItem = New dtDTOItem) to the Page_Load event then it will set the value correctly. What I am trying to figure out is how to initialize the property object without having to do it explicitly. It has to be an extended property because I have custom Get and Set code.
Public Property MyDTOItem As dtDTOItem
Get
End Get
Set(value As dtDTOItem)
[code]....
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Jun 5, 2006
I am building a code behind page that has a public property (MyDTOItem) which is essentially a DTO object (dtDTOItem) Note: In my code the Get and Set are actually real code (I stripped it for the example).
The problem I am having is in the Page_Load event. When I set the .Member1 property of the DTO object the Get code runs and not the Set and therefore the DTO ibject property .Member1 never gets assigned.
I figured out that if I add code (MyDTOItem = New dtDTOItem) to the Page_Load event then it will set the value correctly. What I am trying to figure out is how to initialize the property object without having to do it explicitly. It has to be an extended property because I have custom Get and Set code.
Public Property MyDTOItem As dtDTOItem
Get
End Get
[code]....
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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?
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Mar 11, 2010
what the results I need in a Windows Form Application.
Requirement:
(1) I need to create class objects with all various methods and properties, etc.
(2) I will create only one instance of the each class
(3) I need to be able to call the methods and properties of the created class objects (1) from any form I create.
(4) I use the class objects to store data so that separate threads can access them..
Question: how I would code this into a WFA? (I have console application code that works but need to convert it into a GUI).
[Code]....
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Jan 18, 2011
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:
[Code]...
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Mar 20, 2011
how can i make wizard on certain form ;for example form have question multi choice when i select on of them show next button when i click on next button show next question and choice.
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Aug 19, 2009
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
How can i fix this ?
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Aug 19, 2009
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
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May 6, 2010
If you run this code you will see that the 500 PictureBoxes that are added ( this is easier to show than adding pixels as a pixel is only a single point ) fall mainly on the diagonal.With regard the RANDOM class, why should this be like this when the bounds of the instances are? >>
p.Location = New Point(x.Next(0, Me.Width + 1
), y.Next(0, Me.Height + 1 ))
as in this code.>>
[code].....-2138214fdeb4
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May 18, 2010
I've createda vb.net class library where I've defined a number of small classes... nothing complicated, just working with strings, sending emails, etc.In another project, I reference the class library and I'm seemingly able to create an instance ofone of tclasses - intellisense shows me all of the plic properties, methods, etc... all looks perfect. No compile errors at all, nothing b gumdropsand lollipops.When I run the app I'm working on that references the class library, it fails at the point where I'm creating an instance of the class and gives me a vague exception, "System.TypeLoadException".
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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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May 20, 2010
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.
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Jun 11, 2012
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?
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Mar 7, 2009
there is a way to turn the following code into a sub so I don't have the same boilerplate show form code in use a thousand times in a program:
Example:
Public InstanceOfFrmGeneric As frmGeneric
If InstanceOfFrmGeneric Is Nothing Then
InstanceOfFrmGeneric = New frmGeneric()
[code]....
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Feb 3, 2011
I am converting an old Vb6 solution to .net 2.0 in vs2010. I've been working in C# for about 3 years now and .net for 5. I don't recall having this problem in C#, but if I want initialize a readonly collection of DerivedControlFoo Is there a clean way to do it besides creating a sub to do it all off somewhere else? I'd love to be able to do it at the class level at the declaration for readability and simplicity.
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Mar 12, 2010
When I do this
Public Class cInherits : Inherits Panel
I get this: Base class 'System.Windows.Forms.Panel' specified for class 'MenuButton' cannot be different from the base class 'System.Windows.Forms.UserControl' of one of its other partial types.
How do I inherit?
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