I have been out of VB.Net way too long, I have a custom class in C# that needs to be converted to VB.Net and would like to know the main differences between them. Certain things in C# I cannot seem to do in Vb.Net with classes such as use: public classname or public [classname](DataTable dt) in VB.net
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I know that Structures are value types and classes are reference type, i know that since structures are stored in stack they are faster to use i also understands that structures can not use the Inheritance concept but still in most examples i see i always see that the authors use classes when building something like BBL library, if structures is light-weight compare to classes and i don't need it to be inherited should i use structure instead of class?is there a rule of when to use class and when to use structure ?
View 2 Replieswhat is the difference between these 2 ways to refresh a linq class
1) LinqDB.Refresh
2) LinqDB =
New DataClasses1DataContext
I have got the impression that some time the linqdb.refresh does not work at all
I want to know what are classes , objects , a namespace , subroutines,functions,methods,properties and differemce betweem byval and byref in your words.
View 18 RepliesI already know how to make really basic custom controls where I can pass in new variables to treenodes because of my custom class, but it's not really working out well for me.I figured out how to read the new values & change them while their in the normal treenode because oddly enough once i've passed in an object from my custom treenode class it worked but I want to know a few things.
1.With my custom class, I can't do things like the following.
MsgBox(
New
TreeNode("Today").IsSelected)
If I replace with CustomTreeNode it doesn't work no matter what I do even working with sub/new it always shows a default value instead of what value is, the most I can think of is because sub isn't returning value, but you can't return value in subs, how are you meant to make lines like that work?
2.Also anyways just for sake of having good intellisense & workings is there a way I can make a class of CustomTreeView that's using my CustomTreeNode's so that I can work on things by code in the EXACT same manor I used to given the name is the same but have my new custom values?Currently im stuck passing any changes using the new type & taking it out I type cast over to the custom type again so i can read the values, but I just want was wondering what I need to do to make it work like a real control would.
Anyways is there any way to over-ride the default control or something instead so I can simply add the new variables in there? I want the same functionality of the normal control just with the added variables so I can work with data pertaining to the nodes of each item in the treenode easier.I already used the Tag value to store some information but it's not like that there are 100 different variables to store information & it's not like anyone wants to store lots of values in 1 variable & parse out the one you need, it's possible but if I can create something good here, I want to use whatever I can make instead of taking my time on working on a more painfully difficult to work with, at least later when I might even need even more variables stored pertaining to each of the items.
I'm studying for the MCTS exam 70-536 and have come across the following question:Given the following Visual Basic code sample, which interface must the custom class MyClass implement?
Dim a As MyClass, b As Boolean
a = 42
' Convert using ToBoolean.
b = Convert.ToBoolean(a)
Console.WriteLine("a = {0}, b = {1}", a.ToString, b.ToString)
Before even looking at the possible answers, I can't get past WHY on earth would we be converting the number 42 to a Boolean value?? I tried this and as I suspected it did NOT compile! Is this a trick question or am I missing something? I realized that in order for the code to work, I would need to implement one of the interfaces shown in the multiple choices. STILL, would there EVER be a purpose for this particular conversion?
inherit from two classes in VB.net?We are developing Custom User Controls that inherits from say System.Web.UI.WebControls.Label. We are planning on implementing a bunch of these controls but they will share mostly the same additional properties. We are hopeful about centralising these properties.I have looked into interfaces but it seems they only 'contract' properties you need to implement.
View 2 RepliesI have a custom collection class. The main member of the class is a List(Of T). I did what this article says: [URl] For some reason though I can only foreach my collection once. The second time it tries it goes out of range because the position does not reset after the first foreach. What am I doing wrong?
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I have a Visual Basic .Net 2.0 program. I'm moving the settings from an older settings file, to an app.config program settings file. I'm trying to do this as nicely as possible.
So, I added my setting as shown in this image.
On load I do this:
If My.Settings.databaseConnectionSettings Is Nothing Then
My.Settings.databaseConnectionSettings = New ArrayList()
End If
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So, the question is, how do I get that arraylist of my DatabaseConnectionSettings saved to persistent storage? I want to do this in the cleanest way possible. That is, I don't want to have to convert it to a string or save it to a separate file every-time I want to use it. I would like to be able to use the My.Settings accessor method.
I'm using a DataGrid to display the below custom classes via a BindingSource, I'm trying to figure out a way to save them to a file either by serialization or by some other method. I've tried a lot, but I think it has a hard time serializing because the Account object has the CharacterList object or something. [code]
View 3 RepliesI have several different lists I want to call. They all have the same format for the class:
id, value, description, order.
Instead of creating a bunch a classes to return the all of the many lists, I wanted to use generics and just tell it what kind of list to return. However, I can not figure out how to populate the classes.
Here are 2 examples of function in my calling code. This should indicate the type of list and the stored proc used to get the data:
Public Function getTheEyeColors()
Dim glEyeColors As New GenericList
Return glEyeColors.GetALList(Of EyeColor)("GetAllEyeColors")
End Function
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I have a main application and the setup project for the app in a single solution.I have custom classes to detect in sql server 2005 express is installed. if it is not I have classes to install it and create my database.Now I need to call the above classes from my setup project before it installs my actual application on a client pc.
View 2 RepliesAm in the process of architecting a new windows forms application, and I intend to use Visual Basic 2008 and SQL Server Express 2005. This is my first application in .Net and I really want to observe the best OOD & OOP principles to create an application that is easy to maintain and extend (add new functionality). My issue is in regard to databinding on the UI. From experience, what do you guys recommend to use for databinding? Should I return datasets/datatables from my Business Layer and bind these to UI controls or should I return Business Objects and bind these to UI controls? And what are the pros and cons of each approach?
View 1 Replieswhat is the diff between custom control ,inherited controls adn usercontrol in vb.netadil
View 2 RepliesI Have just been watching a video on throwing Exceptions. Are you supposed to throw System.Exceptions from within your custom classes. to the calling code, Which other way can they communicate. I have read in several places it is bad practice to throw SystemExeptions.
View 3 RepliesI have written multiple programs in the past that deal with cad data. Points, lines, arcs, etc. For each program I ended up creating slightly different versions of some really base classes like a class that defines a point:
<Serializable()> Public Class Point
Public x As Double = 0
Public y As Double = 0
Public z As Double = 0
End Class
My question is how would I use that class in such a way that it could be in a namespace and imported into any future project that I write?
I have two classes, one nested in the other. [code]Neither "Name" or "ID" are unique between operations and records.I wish to construct a dictionary using LINQ = Dictionary(Of String, Of List(Of Integer), whereby the keys are uniqe examples of Names in my collection and the values are the collective set of distinct IDs that are associated with those names.
View 2 RepliesHow can I structure my classes so that the user interfaces though a single class while the supporting classes are hidden from their view? I think its best understood in an example:
Public Class MyInterface
Public Economic as EconomicClass
Public Sub New()
MyBase.New()
[code].....
So you might ask why am I even separating them? It's strictly for others who will be working with this interface. I need to funnel them though a logical structure:
interface.Economic.MyMethod
interface.Currency.MyMethod
etc
This way everything is already handled for them in the background and they only need to run the method they need. I don't know if I can have it both ways in VB.NET.
Here is some example code of what I mean:
vb
Public Class Form1
Private Sub Button1_Click(ByVal sender as Object, e as systemEventArgs) Handles Button1.Click
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I m trying to raise Click event of Textbox explictly but I m getting "Derived classes cannot raise base classes" error.[code]....
View 1 Repliesso far i got
code
For Each item As Reflection.FieldInfo In GetType(NameSpace.ClassWithNestedClasses).GetFields
rtfAppend(item.Name & ":" & Tab & item.GetValue(Me))
Next
For Each item As Reflection.PropertyInfo In GetType(NameSpace.ClassWithNestedClasses).GetProperties()
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which gets me the simple string vars and properties of my top class, but how can i apply this to loop through all sub classes and get there vars and props?
Searching the internet finds no less than 700 different ways and opinions to accomplish what I'm trying to do, and I would just like to know the simplest, most bullet-proof way possible.
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I simply want to extract the string "bar," which is inside <hostName></hostName>I can do this easily enough with simple string functions, but I'd like to do it with one of the .NET XML classes/methods.
I have three classes Employee, Manager and Salesman. Manager and Salesman classes inherits Employee class.
Employee :
Public MustInherit Class Employee
' Field data.
Protected empName As String
Protected empID As Integer
Protected currPay As Single
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Manager :
Public Class Manager
Inherits Employee
[CODE]...
Salesman :
Public Class Salesman
Inherits Employee
[CODE]...
Now I have created a object of salesman and manager using the following code:
Dim objSalesMan as Employee=new Salesman("xyz",1,2000,5000)
Dim objManager as Employee=new Manager("abx",2,5000,"production")
Is this a good programming pratice or should I use:
Dim objSalesMan as new Salesman("xyz",1,2000,5000)
Dim objManager as new Manager("abx",2,5000,"production")
This is what I would like to achieve:To create a custom messagebox, with varying number of buttons with custom .Text descriptions, and other features. I intended to have a property array that would be redim-ed and have values (.Text values) set by the calling class:
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I came across this great article on creating a custom datagridview column which creates a graph-like effect in the cells of a custom datagridview column:[URL]..Does anyone know how you would edit this to format the number in the cell as a percentage? And does anyone know how you would set this up to take 0 values which do not create any graph effects at all.I have been trying to do this but keep getting errors.
View 1 RepliesI was trying to block the closing of a custom combo box popup window in my custom DataGrid. The popup window comes by pressing F4 or ALT+DOWN keys in my datagrid which is getting closed if I press the down arrow for the first time, after showing the first value in the combo box as selected. Next time onwards, if I press the F4 key and down arrow, I can move to any item in the popup window and select the item using keyboard and in that case, the popup window is not getting closed till I press the ENTER key or selection using the Mouse. Is there any specific reason for this behaviour or something is missing in my code part? [code]...
View 1 RepliesI was trying to block the closing of a custom combo box popup window in my custom DataGrid. The popup window comes by pressing F4 or ALT+DOWN keys which is getting closed if I press the down arrow for the first time after showing the first value in the combo box as selected. Next time onwards, if I press the F4 key and down arrow, I can move to any item in the popup window and select the item using keyboard and in that case, the popup window is not getting closed till I press the ENTER key or selection using the Mouse.
View 13 Replieshow to specify a custom icon for display in the toolbox window when you create your own custom control? Something other than the dreaded "gearbox" icon.
View 2 RepliesCookies to be stored in folder and on close delete the cookies The ability to watch youtube vids, view images, and play js/flash games good security, no ads?
View 6 RepliesI'm using custom serialization and when the xml is generated it's putting the class name as the root element
Example:
<MyClassName>
<MyIntendedRootNode>
<ObjectType>
[code]....
I'm invoking the serialization by calling xmlserializer.Serialize(writer,Me) so I'm sure that has something to do with it.I've tried putting XMLRoot onto the class, but I think as vb is compiling this partial class with its aspx page, it's either overwriting this property or ignoring it entirely.I'd like to just tell it to either throw away everything it has and use a different root element.