I have a project in Visual Basic 2008 where there is a Main Class and couple of classes inside the Main Class. I want to be able to share variables/objects within the Main Class and SubClasses while those vars/object are instanced.
Ex:
Code:
Public Class clsMain
Public t as New clsSub1
[Code].....
So, can i make var1 be in separate instances per clsMain in the memory while being able to access the var1 in clsSub1?
I've heard bad things about overusing regions but when adding enums to my classes I put them into a #region "Enums" at the end of the class, and do the same with structures and even subclasses.
Is there a better/standard way to go about grouping such elements on classes?
(Note: this is tagged C#/VB but maybe the same situation exists for other languages, like Java)
I am a VB6 programmer learning VB.Net and am having trouble with the following concept.
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I have a problem with inherited classes. Have a look at the following VB.NET 2.0 / VS 2005 code:
MustInherit Class templateclass
Public Shared x As String
End Class
Class child1
[code]....
The templateclass has a shared variable x which is of course inherited by the child classes. But I wonder that all child classes share only one x! Until now I thought that shared variables are only shared among the instances of a class, not among all childs. This is very annoying because I have a base class which I need in two slightly different versions and they should not "share the shared" variables. And because the classes have a lot of shared variables, shadowing each in the childs would be very..
Consider the following extension method:
<Extension()> _
Public Function Satisfies(Of T)(ByVal subject As T, ByVal specification As ISpecification(Of T)) As Boolean
Return specification.IsSatisfiedBy(subject)
End Function
This works as expected if subject is the exact class being operated on by the specification. However, if the specification is examining the super-class of T, this extension will not work unless subject is explicitly cast to the super-class. Is there a way I can avoid this? So far, the best I've been able to come up with is:
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Since I (apparently) can't get this to work exactly as I'd like in VB.NET due to limitations in the language itself, is my second attempt the safest/most efficient way to do this?
I'm want to serialize a list(of Animal) of objects with different subclasses of type "their own type" but getting nowhere as exceptions doesn't give out any useful information. I've set up the serializer method which which serializes individual sublass objects if I declare them with their own type but not if I declared them as a derived (Animal).
Code is below:
Public Sub XMLPersistAnimalList(ByVal filePath As String)
Dim serializer As New XMLSerialization(m_animalList, filePath)
serializer.Serialize(Of List(Of Animal))(filePath, m_animalList) '------doesn't work!
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Let's say I have the following class structure (simplified from my real-world problem):
Public Class PC_People_Container
Private _people_list As New List(Of PL_Person)
Public Sub New()[code].....
If I were to serialize this, I'd get the default assigned node names in my XML. That means my root is named PC_People_Container and each person in the list is marked up as PL_Person. I know I can change the root node using <XmlRoot(ElementName :="PeopleContainer")>. The trouble is doing that for the subclasses. I can't use the <XmlRoot> tag on PL_Person class because there can't be two root elements, and IntelliSense throws a fit when I try to use the <XmlElement> tag on a class like I would on a property. Is it even possible to control what those subclasses are named when they're serialized as child nodes?
I searched around the web for some tutorials and code examples, but couldn't find anything up to date. For example if i wanted to hit the "+" button on the windows calculator using an application i made what would be the best route to do so?
View 3 RepliesI am lookin for source from where i can learn to change control properties at runtime using VB.NET. Actually I havent started working on the project so I cant mention exactly what I need.
View 4 RepliesI 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.
I am trying to have a ComboBox on my form, be able to change the selected item in a Listbox/Combobox on a website, through a webbrowser control.
For instance, here is the HTML coding I am trying to interact with on the webpage:
<select name="day">
<option>1</option><option>2</option><option>3</option><option>4</option><option>5</option><option>6</option><option>7</option><option>8</option>
[Code].....
I want to be able to make Internet Explorer navigate to the "about:blank" page every time its user navigates to a wesite that is blocked by the HOSTS file. Does anyone know the code that I can use to do this?
View 18 RepliesWhat classes has vb.net got to work with video files...like mpg or mp4i wanna write some code to be able to save a specific video frame to a jpg image.
View 1 RepliesI have a MDI parent on which i launch a child form
Dim NewMDIChild As New Frm_addOT
'Set the Parent Form of the Child window.
NewMDIChild.MdiParent = Me
'Display the new form.
NewMDIChild.Show()
His child form contains several comboboxes which hold data from a dbase(sql)
When new data is entered in the cmb it checks the database and if it isn't in there it launches another window
FRM_OTlistaddklant.Visible = True
and copy's the newly entered text in a textbox.
FRM_OTlistaddklant.TB_klantnaam.Text = OTaddklant_naam
then i can give in the details etc.
now, when this is done and the users presses a button "Add"
the information is written to sql(which works perfect)
than i have a public sub on the Frm_addOT which should refill the combobox and
also set the backcolor to a specific color.
and the last two things will not work. Actually when i try to change the backcolor on Frm_addot it triggers the event backcolorchanged and says it has changed but it is not visible.
I'm trying to start to use the Task class for multi-threading. This is a really simple example so I can work out the ins and outs. As an example, I have the below thread, the thread.sleep is used to represent large amounts of data processing, at the end of which I'd like to update something on the screen. Please advise a good way to achieve the idea of the below code with respect to the text box update.
With the old threading system, I would grab the UI context, and do a .post/.send to it. I'd like to have that ability with the newer task system, but am open to the preferred way of solving this.
As a back ground, the threads I will be replacing were previously constantly running during the app with a do/while that was killed at app close.
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I want to make a usercontrol that I can then use on my project form, and then interact with it. (for example, get the result of a calculation that was made in the user control and then make futher calculations on my form) I basicly know how to make a Usercontrol, by not how to use the information that it derives for further use.
View 3 RepliesI just wondered if it was possable to say load a webpage then press a button on a certan webpage?
View 9 RepliesHere 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 am using VB.NET to automate a web form submission using SHDocVw.InternetExplorer. I have navigated to the form, filled in all of the fields successfully, and clicked the update button. By design the web application then opens a JavaScript SubModal window in the center of the screen. It looks like a "floating iframe" for lack of a better description. [code]I need to find a reliable way (i.e Not SendKeys). to get the HTML source of this popup in order to click a button.
View 1 RepliesI am writing (and teaching myself how to write) an experimental assembly in VB.NET 3.5 that is exposed via COM and then called from some Excel VBA code to initiate an instance of a class that traps some Excel events and then perform some functions on the active workbook in Excel.To initiate the class, a reference to the Excel Application is passed from the VBA (I am using a PIA for Excel in the assembly).I needed to perform a time-consuming operation on the active workbook from my assembly so I decided to use a BackgroundWorker in a WinForm so that I can display a progress dialog for the operation whilst the operation completes in the background.
I would like to know if there are any problems with interacting with Excel via COM using a background worker in this way? Reason for asking is that the main class in the assembly holds the reference to the Excel application object, and this is then passed to the BackgroundWorker so that it can determine the active workbook and then perform some operations on it. I am only accessing the workbook itself (not other objects) through one procedure.
following error as I am unable to find a fix:Description:A problem caused this program to stop interacting with Windows.
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I didn't know where to post this question so I hope I put it in the right forum...I am not new to Visual Basic, however I am definitely not an advanced user. I would like to build an application that would allow me to interact with other programs on my computer. For example, if I were to build an application that could control iTunes, how would I go about this?
Or, I am looking to make an application that would allow me to do little things on my computer like disable my track pad if I have a mouse plugged in. How would I build something that could interact with windows (or iTunes) like that?
I have a windows form that I would like to have search for an html button in the user's browser. I would need the location of the button on the screen.
View 4 RepliesI have a windows form that I would like to have search for an html button in the user's browser. I would need the location of the button on the screen
View 13 RepliesI have a method that is asynchronously called when System.Net.Sockets.NetworkStream.BeginRead completes.
skDelegate = New AsyncCallback(AddressOf skDataReceived)
skStream.BeginRead(skBuffer, 0, 100000, skDelegate, New Object)
In that callback method, I need to interact with the UI thread.
Sub skDataReceived(ByVal result As IAsyncResult)
CType(My.Application.OpenForms.Item("frmMain"), frmMain).refreshStats(d1, d2)
End Sub
This causes an exception after the method completes. (when End Sub is executed)
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If only there were an easier way of traversing ASP.NET controls in the codebehind. This has been the bane of my existence as an interning .NET developer. entifying the proper member of the ListView controls. I've deleted all the presentation code in the markup to make it easier to look, since it isn't relevant anyway. Here's the situation:Markup
<asp:ListView ID="NewProduct" runat="server" DataSourceID="NewProductSDS" DataKeyNames="ID">
<ItemTemplate>
[code].....
I have a windows service application that is meant to interact with SQL server database (INSERT, UPDATE, ETC). The windows service application is also multi-threaded.I created an "App_Data " folder to keep my database and used app.config file for connection information, etc.
After installing and starting the service, nothing happens, the database doesnt get updated, etc.
Has anyone ever written a windows service application that interacts with a database? Kindly advice me on how to overcome this problem..
I m trying to raise Click event of Textbox explictly but I m getting "Derived classes cannot raise base classes" error.[code]....
View 1 RepliesI'm trying to put together a simple GUI for ffmpeg (a command-line video conversion, encoder, decoder etc..), mostly for video encoding/conversion... Now I am able to interact with ffmpeg.exe (the command line app that does all the big conversion work) with the System.Diagnostic.Process class (I know how to start the process with the arguments I need etc..) But the problem is, when I'm converting a moderately long video file it can take several minutes to complete...
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