Usage Of Interfaces To Implement Multiple Inheritance?
Dec 15, 2011Can any one explain the usage of interfaces to implement multiple inheritance in VB.NET.
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Implement Without Multiple Inheritance?
Sep 1, 2011I have a library of graphical controls used to display values from a remote device. The controls are typically graphical objects such as a digital meter, analog meter, vertical bar, etc. I first create these controls with a value property. The control will display the value property, e.g. the meter needle will move to the position representing the value.
The next thing I do is to create a new control that inherits the previous discussed control. The new control adds properties that allows the value to be set from values retreived through a communication component. My code that does this is 99% the same for all of the controls. Since I already inherit the graphical control, I can not inherit the class that retreives the values from the communication component.
[Code]....
Oop - Inheritance And Interfaces ?
Jul 14, 2011Has someone a hint what I'm doing wrong in VB.Net?
Module Module1
Interface ISearch(Of T As ISearchResult)
Function ids() As List(Of T)
End Interface
[CODE]...
The third cast isn't working. Why? did I miss a oop lesson?
A To Z Usage Of Interfaces In .NET?
Dec 30, 2011In this discussion let us discuss every usage of interfaces in .NET. Any real time examples and difficulties in using interfaces can also be discussed here.
View 6 RepliesHow To Use / Implement .NET Controls/interfaces
Aug 25, 2011I am a VB programmer of some 13 years. I started briefly with VB5 back in the mid-to-late 1990s, but then quickly moved to VB6 which I did for several years on PCs and HPCs (CE 1.x devices).I have done .NET 2002, 2003, 2005, and 2008 each for stints, intermingled with VB6 coding, at various jobs. But, I never got formally trained on VB.NET. In fact, I taught myself VB5/6 too. I have a degree in Computer Science and Mathematics, but the university CS program only had Unix systems. I basically learned everything I know on the fly from various Microsoft Press and other company's books (and the MS website/MSDN CDs too) while doing projects.I was wondering what everyone would suggest to really learn the .NET workings and why they are setup like that for Windows client/server applications. It doesn't have to be technical and brain-numbing.I have recently run into things dealing with MSFlexGrid vs DataGridView and how they link/work with database sources that confounds me. And, I am assuming there's just something I don't know about how/why VB.NET works the way it does...and I want to learn it to become a better developer.I want kind of that fun book that's easy to read, is thorough in that it teaches you a wide range of how to use/implement .NET controls/interfaces, and will fill in the gaps in my knowledge and experience.
View 1 RepliesSpecify The Interfaces An Argument Must Implement?
Nov 3, 2010I have an interface called IBaselineControl. Now I'm trying to write a procedure which requires, as an argument, a Control which implements the IBaselineControl interface. However, I don't know the syntax for this. VB.Net allows us to require multiple interface implementations along with class inheritance when writing constraints for generic types. The syntax used there suggests that something like this might work:Public Sub Test(X As {Control, IBaselineControl})Unfortunately, that syntax doesn't work and I'm unable to find any syntax which does.
View 6 RepliesRedeclare Things To Implement Interfaces?
Nov 26, 2009I have an interface IMyInterface and this interface implements a method MyMethod.I have an object MyObjectBase. This object contains a(the same) method MyMethod.1) If now I do MyObject Inherits MyObjectBase Implements IMyInterface need I to redefine? (shadow, override) MyMethod in the MyObject class?
View 2 RepliesCreate An Implement Interfaces In The Data Access Layer?
Jan 15, 2010I typically dont create interfaces unless i have to, however in my current application i have to create interfaces in the Data access layer. I'm a in a minor confusion that hwo do i create those interfaces more how to implement them: the following code might make things clear:I have the following class and interface in the data access namespace
[code="vb"]Imports ConsoleApplication8.BusinessLayerImports ConsoleApplication8.DataAccessLayerImports System.DataImports System
Namespace DataAccessLayer
Public Class CountryGateway Implements ICountryGateway
[code]....
1. Is this way implement the interface in the data access layer? (in this case the class CountryGateway access the database.)
2. I have been told that we should create interfaces than abstract classes espcially in the data access layer, is there a particular reason for this?
Forms :: Any Way To Implement Inheritance Concepts?
Jul 4, 2009I m new to vb.net need some ideas about how to implement inheritance concepts in vb.net
View 1 RepliesHow Variables Declared With Protected Access In A Base Class Are Used To Implement Inheritance
Jul 29, 2010how variables declared with protected access in a base class are used to implement inheritance.
View 1 RepliesMultiple Interfaces With .NET?
Aug 6, 2009Im building a game with VB.NET I designed the core of the game in form1 window But now I need menus. How can I implement this without having 5 or so windows that I show() and hide() ? Doing that slows it down a lot and uses lots of memory. I tried tabs, but I don't want the tabs to appear, just switch. Whats the best way to implement multiple interfaces?
View 1 RepliesUsing The Same Event For Multiple Interfaces
Oct 17, 2011how to do something that seems that it should be simple.
I tried it on a larger project I'm working on and got an error, so I reduced it to the simplest possible that I could find:
Public Interface IF1
Event WakeUp(ByVal TheObject As Object)
End Interface
[Code]....
Interfaces - Implementing Interface For Multiple Class
Oct 21, 2009I'm dealing a problem in implementing interface for multiple class.
Assuming I have a class named Class Unu .
I created an interface called Test for those 2 classes.
The first class Unu has 2 data members(i=12 and j=12.17). When you run the program it stores the result on screen 24.17
The second class called Doi has 2 data members(a=20 and b=32.17).
What I want now is to do the same thing for data members a and b so that it stores on screen 20+32.17=52.17
My problem is that I want to be displayed also the result for the 2 data members for the second class on my screen. I implemented the interface on class Doi but I cannot see why he isn't displaying me the second result 52.17.
What I must add to my code to do that?
Here's the full code:
CODE:
.net Multiple Inheritance In An Interface?
Apr 15, 2011I'm facing a problem regarding multiple inheritance in VB.net:As far as I know VB.net does not support multiple inheritance in general but you can reach a kind of multiple inheritance by working with interfaces (using "Implements" instead of "Inherits"):
Public Class ClassName
Implements BaseInterface1, BaseInterface2
End Class
That works fine for classes but I'd like to have an interface inheriting some base interfaces. Something like that:
[Code]...
Get Around Lack Of Multiple Inheritance?
Nov 5, 2009get around lack of multiple inheritance
View 2 RepliesGetting Around Lack Of Multiple Inheritance?
Aug 24, 2010I am currently working on a framework for applications developed by my company, my boss wants to have a switchboard and a MenuStrip, where the entries and their actions are controlled by a database.
Now I've dealt with all the code to get them working. But the problem that I am facing is that I have duplicated code because each of the classes have the code that deals with ensuring the user has the right privileges and the code to deal with when a user clicks on an item.
Normally I would move this code out into a class and then have each of the classes inherit from the class, but because the switchboard already inherits from the Form class and the customised MenuStrip inherits from the MenuStrip class.After doing some Googling the only answer I have been able to find it using an interface for the functionality, which is obviously not exactly what I want.
Anyway I was just wondering whether any one had any suggestions on what I could do to deal with this problem, as I would like to avoid having duplicate code as much as possible.
VS 2010 How To Get Around Lack Of Multiple Inheritance
Aug 31, 2010I have a class, GControl. It's pretty much a Control class clone with some improvements. It doesn't inherit from Control, because that would be a huge mess, and it needs to stay that way. However, to add a GControl to a Form in the first place, it needs to inherit from Control. So, I created a new class, called GForm, that inherits from Control and draws GControls in the OnPaint method. However, it should also inherit GControl, because it needs (1) to be able to be a GControl's Parent and (2) to be able to have a GControlCollection property. The way I've made the GControlCollection is so that it must be created with a GControl as its parent. I could change how GControlCollection works, but not the Parent property. Does anyone know a way to get around that?
Here's what the property looks like:
CODE:
And a few methods (like Invalidate()) need to be called on the control's parent.
Storing An Object That Implements Multiple Interfaces And Derives From A Certain Base (.net)
Dec 7, 2010In .net, it's possible to use generics so that a function can accept arguments which support one or more interfaces and derive from a base type, even if there does not exist any single type from which all valid argument types derive. For example, one could say: Sub Foo(Of T As {IInterface1, IInterface2, SomeBaseType})(Param as T) And be allowed to pass any derivative of SomeBaseType which implements both IInterface1 and IInterface2. This will work even if SomeBaseType does not support Interface1 and Interface2, and classes which do implement those interfaces don't share any common ancestor that also implements them. This can be very convenient if one won't need to keep the parameter anywhere after the function has exited. Unfortunately, I can't figure out a way to persist the passed-in parameter in such a way that it can later be passed to a similar function, except perhaps by using Reflection. Is there any nice way of doing that?
The closest I've been able to come up with is to define an interface INest (perhaps not the best name-- thus:
Interface INest(Of Out T)
Function Nest() As T
End Interface
And for any interface that will be used in combination with others or with base-class "constraint", define a generic version as illustrated below:
Interface IFun1
' Any members of the interface go here, e.g. ...'
Sub DoFun1()
[CODE]...
A class which will support multiple interfaces should declare itself as implementing the generic ones, with itself as the type argument.
Class test123a
Inherits sampleBase
Implements IFun1(Of test123a), IFun2(Of test123a), IFun3(Of test123a)
End Class
If that is done, one can define a function argument or class variable that supports multiple constraints thusly: Dim SomeField as IFun1(Of IFun2(Of IFun3(Of sampleBase)))
And then assign to it any class derived from sampleBase, which implements those interfaces. SomeField will implement IFun1; SomeField.Nest will implement IFun2; SomeField.Nest.Nest will implement IFun3. Note that there's no requirement that IFun1, IFun2, IFun3, or sampleBase share any common derivation other than the generic interfaces inheriting from INest(Of T). Note also that, no matter how many INest-derived interfaces a class implements, it only needs to define one implementation of INest(Of T).Nest. Not exactly beautiful, but there are two nice things about it: (1) any concrete class which in fact implements the necessary interfaces can be assigned directly to a field declared as above, without a typecast; (2) while fields which chain the types in a different order are not assignment compatible, they may be typecast to each other. Is there any better way to store something in such a way that it's "known" to support multiple interfaces and derive from a certain base type? Given that one can write such code in a type-safe manner, it would seem like the .net 2.0 CLR could probably support such a thing quite nicely if compilers offered a little assistance.
Storing An Object That Implements Multiple Interfaces And Derives From A Certain Base (.net)?
Jan 24, 2012I was looking through some legacy code we have and I noticed something that struck me as particularly odd.Say we have the concrete class TestClass. TestClass implements the interface ITestClass.What sort of behavior should I expect in the following case, then? (I didn't realize this was even possible)
Dim testClass as TestClass = Nothing
Try
testClass = New ITestClass
[code].....
Asp.net - Implement Security Trimming With A Website With Multiple Folders And Multiple Web.config Files?
Jun 18, 2012I have a website that has highly granulised access and hence requires many web.config files. The problem is I would like to trim the menu so that only certain users will have access to certain folders. I have enabled trimming and setup roles in the sitemap, however when I access the page the menu is not show, as I am authorized to view the default page which is not in a subfolder. When I type the url of a page in sub folder's I have access.
How should I handle this:
A site map for each web.config file - don't know how this will work Removing the sub web.config file to only use a single one
Any Real Example Of Using Interface Related To Multiple Inheritance
Dec 18, 2009I m trying to understand Interfaces so that I can implement them in my programs but I m not able to imagine how should i use them.Also give me some eg of using them with multiple inheritance in C#
View 9 RepliesVb 2005 Form Inheritance - Multiple Forms Are Opened?
Nov 7, 2011Several years ago, I created a nifty data entry form that is called from a main menu. Due to recent user requirements, I had to create another form that is very similar to the data entry form. To prevent duplicate coding and testing, I created a class to inherit the existing data entry form. The issue is when I leave the class and return to a sub menu, the class is opening the main menu and the sub menu. How do I only return to the sub menu without the main menu appearing? Here is a snippet of my code. You'll have to scroll down to the very bottom to see the section that is causing issues. BTW, I coded the application in such a way that only one form should be open at a time.
frmMenu (main menu). This is nothing more than a bunch of buttons that allows the user to perform various functions.If user clicks button #1, open the data entry form:
Dim objFrm As New frmDataEntry
bolOkToCloseForm = True
Me.Close() '--- close the menu screen
[code]....
Usage Of Colon (i.e. : ) For Multiple Statements?
Jul 27, 2010Usage of colon (i.e. : ) for multiple statements?
View 1 RepliesVB Memory Usage - Open The Form That Is Linked To Multiple Tables - It Jumps To 157 Mb?
Aug 1, 2011I have an VB application that I developed in Visual Studio 2008. The back end is SQL. Application stores quite a bit of information and gets updated daily by users. It also connects to AD to get u/p, adds new accounts in AD and adds mailboxes. Users connect to it through Citrix. We noticed big spikes in memory usage. The executable itself is less than 5Mb; if I run it and it opens main form - memory usage jumps to about 19Mb, open a report - it jumps to 80 Mb. If I open the form that is linked to multiple tables - it jumps to 157 Mb. Once users start pulling new information in, update it and connect to AD or Exchange - it could jump to 250 Mb. Also noticed that if user with read only rights has application opened and idle - memory usage constantly changes with a pattern
like 17Mb - 19 Mb - 15 Mb - 17 Mb and so on. This user wasn't even using computer at the time. In general - what could cause such jumps in memory usage? What is the best way to prevent it? On the server we have Windows Server 2003 SE
Implement Multiple Threads In Application
May 12, 2010I need help to implement multiple threads in application.Assume ds.table(0) has 5 and sometime 6 rows rows for i=0 to ds.tables(0).rows.count-1.I have to apply multiple threads, means all five/six rows should start at once using thead and "Process 1" .."Process 4" should also handled by threads.This is hierarchy that I have to apply with threads, how can I do it. It is requested to put piece of code so I can understand better.
View 13 RepliesVS 2008 Implement Multiple BackGroundWorkers?
Mar 24, 2009I am making an application that has a tabbed interface. Each tab uses a UserControl with the controls that I need on it. The user enters some data & clicks a button, which starts a lengthy process. I would like to run that process in a BGW, so that the user can switch to (or open) another tab & process another set of data simultaneously.
View 7 RepliesImplement The AutoComplete Functionality For Multiple Word In A Textbox?
Aug 4, 2010I am using Visual Basic 2010 Express to develop my windows application.
I am developing an application wherein I need a functionality similar to the outlook email address.
In outlook, we are able to enter multiple email addresses in "To" address box. When typing first few chars of an email, the AutoComplete functionality displays the list of possible email addresses. Either we can select from the list or we can continue typing. As and when we type email addresses, the AutoComplete functionality shows the list of possible email addresses for every email address that we type in the textbox (if anything is there). I am trying to implement this functionality in my application
I found there is a AutoComplete functionality for textbox. below is the code
[Code]....
I know that the AutoComplete is only for one word and not for multiple.
But How to implement the AutoComplete functionality for multiple word in a textbox?
Get The Current Number Of Usage Days, Unique Usage Days, Etc In An Evaluation License Using CryptoLicensing Generator?
Jan 25, 2010Get the current number of usage days, unique usage days, etc in an evaluation license using CryptoLicensing Generator.
View 1 RepliesAre Interfaces Used Often
Oct 16, 2009Are Interfaces used often? Need opinions.
View 4 Replies.net - Casting Interfaces And MEF?
Mar 13, 2009I have the following problem with MEF: Interface definition to be used by host:
Public Interface IExecuteDoSomething
Inherits IAddinSettings
Event DataReceived As EventHandler(Of DataReceivedEventArgs)
Function DoSomething() As Boolean
End Interface
[Code]...
Everything seems to work fine until the Button2_Click routine is executed, then an InvalidCastException is thrown with the info:Unable to cast object of type 'System.Collections.Generic.List1[SharedLibrary.IExecuteDoSomething]' to type 'System.Collections.Generic.List1[SharedLibrary.IAddinSettings]'.
How can i solve this problem, because the imported object implements both of the interfaces?