.net Multiple Inheritance In An Interface?
Apr 15, 2011
I'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]...
View 3 Replies
ADVERTISEMENT
Dec 18, 2009
I 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 Replies
Jan 6, 2012
How can I convert following code to VB.NET?
class A
{
public int NumberA { get; set; }
}
[code]....
In VB.NET there is problem with Implements keyword after property declaration. So I need to do something like this:
Class B
Inherits A
Implements IC
[code]....
But there is duplicit misleading property NumberA1.
View 3 Replies
Feb 15, 2010
I've got an interface inheritance issue that has been vexing me for some time. It doesn't seem to make any sense, and I can only conclude that I'm missing something fundamental.
Overview The code below is from part of a fluent interface for our ORM tool. It provides a SQL-like syntax for pulling data from the database. You don't have to completely grok all the interrelations to understand the problem -- the real issue is the EndClause method.
The EndClause Issue There's a method called EndClause that doesn't show up in one expected spot -- IOrderQueryRoot. As far as I know, it should show up because it inherits from two different interfaces that both have a method called EndClause, but when I consume an object that implements IOrderQueryRoot, EndClause does not pop up in intellisense.
There are some more implementation details below.First though, if you look at IOrderQueryRoot (which contains EndClause), you can see that it inherits IHasOrderLogicalOperators, and also IHasOrderFields (which also contains EndClause).
Public Interface IHasOrderLogicalOperators
Function [And]() As IHasOrderFields
Function [AndNot]() As IHasOrderFields
[code]....
At this point, the interface is working fine -- if I were to remove this method, VS would scream that I have to implement both EndClause methods. The problem is one level down, when the "end developer" is trying to actually write code against the interface.
View 1 Replies
Jun 18, 2010
This question is a follow-up to my last question with a reference to COM Interop. Let's say I have the following 2 interfaces and implementing classes:
[Code]...
Interfaces are important in COM interop for exposing properties and methods to IntelliSense in the VB6 IDE (per this article). However, because ICartItem is inherited from ISkuItem, SKU is not explicitly defined in ICartItem and thus is not visible in IntelliSense in VB6 and even throws a compiler error when trying to write to objCartItem.SKU.
I've tried using Shadows and Overloads on the SKU property in ISkuItem, but then the compiler wants me to explicitly implement SKU for both ISkuItem and ICartItem within the CartItem class. I don't think that's what I want. Is there a way (in either VB.NET or C#) to explicitly declare the SKU property in ICartItem without having to declare SKU twice in the CartItem class?
View 2 Replies
Nov 5, 2009
get around lack of multiple inheritance
View 2 Replies
Aug 24, 2010
I 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.
View 2 Replies
Sep 1, 2011
I 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]....
View 5 Replies
Aug 31, 2010
I 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.
View 8 Replies
Dec 15, 2011
Can any one explain the usage of interfaces to implement multiple inheritance in VB.NET.
View 6 Replies
Nov 7, 2011
Several 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]....
View 1 Replies
Sep 10, 2009
I downloaded a .net component that I would like to make consumable by COM clients. This component allows one to create a DXF file (Cad drawing). The problem is that the component is composed of quite a few class files, some inherit another. All the examples I found only show one file no namespaces etc. [Code]
View 1 Replies
Nov 29, 2009
is there a way to create an interface of delegates? Sub dostuff(byval arg1 as dele1)works, problem is that i have 8 delegates, so i will have to give it 8 signatures. that isn't so bad, but the problem is that when there are various combinations of signatures it gets real real bad.
Sub dostuff(byval arg1 as [Delegate])works, but it allows me to accept delegates beyond the 8 that i wanted (it's like declarign arguments with base Object)could i be able to do this:
Sub dostuff(byval arg1 as Idele1to8)
View 1 Replies
Feb 1, 2010
I am trying to set-up a mutiple choice test and I only want the questions to show up on one form and not multiple forms. How do I do this? I want the user to answer the questions and then click a continue button and the next question will appear on the same form.
View 9 Replies
Feb 12, 2009
I'm working on a small app that takes a series of screenshots to analyze a graph. The problem I'm having is that, on my 3-monitor setup, the screenshot works fine on the primary monitor, but when I drag my app to either of the other monitors, the screenshot is black. I've also tried taking screenshots of the other monitors while the app is in the primary monitor by feeding the coordinates into the CopyFromScreen call directly, and that works, but as soon as I drag my app to one of the other monitors, all my screenshots are black. Also, and I'm pretty sure this will be important later, my primary monitor is attached to the on-board video, whereas the other two are attached to a separate video card. Both the on-board and installed cards are ATI Radeons.
Here's the screenshot code I'm using:
Code:
Namespace ScreenShot
'/ Provides functions to capture the screen, in whole or part
Public Class ScreenCapture
[code]....
View 2 Replies
Nov 16, 2010
I have multiple bitmaps(i) in arrays, and I want to know if I can save each of these bitmaps into on animated gif file. I thought about using image.saveadd() but i'm not sure if that will work.
View 2 Replies
Apr 8, 2011
I have a strange problem; on my form there is a TabControl, and every tab contains a DataGridView.I set all DataGridViews Autosize column property to DataGridViewAutoSizeColumnsMode.Fill and then I set for every column the width with FillWeight, using the same set of values for every DataGridView.Although all these DataGridViews should look the same, the one on the first TAB looks different, it looks like I used different FillWeight values.All others DataGridViews on subsequent tabs looks the same, only the one on the first tab looks different..
View 2 Replies
Oct 4, 2009
How to work with multiple combobox. I have several combobox. I it to have same itemlist and set a default value for this.I used to do:
Code:
Dim MyItemToBox(3) as System.Object
For i as integer = 0 to 3
MyItemToBox(i) = "A" & i
Next
[code].....
View 1 Replies
Oct 21, 2009
I'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:
View 6 Replies
Feb 17, 2012
I have a program that is accessing many similar tables using a linq to sql datacontext. Do linq to sql tables implement a common interface? I would like to write methods that could work with any of the similar tables, so it would be great to do something like
Dim myTable as ILinqDataTable
If switch = "TableA" then myTable=myDataContext.TableA Else myTable=myDataContext.TableB
[Code]...
View 1 Replies
Aug 28, 2008
I don't know the best way to use multiple forms in VB, but I have created a problem and I'm not sure where it came from or how to fix it.
Background: I start the program at Sub Main. This is the main function:
Code:
Module modFunctions
Dim frmD As frmDAQ
Dim frmT As frmTrendView
[Code].....
it works, but I don't want to have to change the entire project.
View 1 Replies
Feb 16, 2009
insert images in a combobox. I understood the code, but what I'm asking is how do I add multiple images per line of the combobox?? I mean the way, the smileys are displayed in dropdown grid in Yahoo! messenger or the sort when you click on the smiley button..
I'm using Microsoft Visual Basic 2008 Express Edition with .NET Framework 3.5
View 1 Replies
Jun 8, 2010
How do i amend my Notepad assignment to support MDI interface multiple concurrent files
View 1 Replies
Nov 14, 2008
I need to be able to add (specific) special characters to text boxes. Problem is, there are five of them spread across two forms and three tabpages. What I'd like to do is bring up a form when the user presses something like "F2" while the text boxes are focused, then on that form would be a grid of buttons. When the user pushes a button, the character is added to the box. How do I get this form to reference the box that called it without passing a global variable or calling a public function? I tried Form3.Parent.Name, but that always seems to refer to nothing. Also, once this is done how can I get it to just insert a character where the cursor on the calling box is? It probably shouldn't even be on a form either since that will take the focus when it's called (which I don't want)
View 3 Replies
Oct 20, 2008
The Title says it all Adding Multiple Checkboxes on FormLoad Depending on Amount of Items In Database. [code]
View 4 Replies
Feb 23, 2010
I've drawn a graph where each gridline represents 15 minutes. (Every 4, 1 hour of time)The resolution is 100 dpi per inch. Each column is 12 DPI. (Not very big)Each gridline can have zero to multiple "Lines of data" which must be centered under the associated gridline using a vertical transform. (Each drawtext label represents an event that happened at that point in time)This I can figure out. The problem is that there can be 3 labels at 3:00AM, then another 2 labels at 3:15 AM with more labels as time progresses through the day. If each "label takes up 24 dpi of space, I need to center 120 dpi of data under 12 dpi of space.(Drawing the lines from the gridline to the associated data should not be an issue depending on how the "label is centered)How can I center all 5 labels at runtime. I've considered an array but each time a "label" is added, I would have to recaculate each labels position. Besides that, how can my program recgnize that the data it is coming up to (data is read one line at a time) is a group or how large the group is?
View 17 Replies
Jan 12, 2010
how to create a user interface in a game such as the application XFire using Visual Basic?
View 3 Replies
Oct 19, 2008
I'm working on a design project where I have to use a Graphical User Interface that contains a drag and drop form. It consists of having a window dropped on a wall. Both of them are images to scale. I would like to know what kind of code I would have to use to show the x and y coordinates of one of the points of my window when dragged so when I drop it, I'm dropping in it on the desired coordinate of the wall.
View 2 Replies
May 18, 2012
I was wondering if I could elicit some tips on how to procede with an interface design approach.That is. What is a good way to go about establishing a "work area" where one can have multiple "floating forms" in this area.Can you have a form which occupies the entire windows desk top and the other forms "float" in this space? the "floating" forms would need to interact with each other where pressing buttons etc on them would affect other forms on the "workspace") Or what would be a good way to start accomplishing that? Or is there a better way to get the same effect?
View 4 Replies
Apr 21, 2010
I'm trying to make a .dll that contains a lot of basic functionality that a program can use. Currently i am trying to use interfaces to make a lot of this functionallity independend of the program using it but i hit a snag. The Basic idea is that a programmer will create his own object using the interface discribed in my .DLL file. Then implements those functions as he likes. He can then instanciate a controller (found in the same DLL) and sends his custom object implementing the interface to that Controller. The controller can then be started and will take over all the work. I do not know what type of object is send to the controller and idealy i want to program it in such a fashion that i shouldn't care as long as the object send implements that interface.In code I am trying to achieve the following: (quite simplyfied)
.Dll:
Code:
Public Interface MyInterface '<----Decleration of the interfaceFunction GetData() As Integer
Function SetData(Data As Integer)
end interface
[code]....
this propperly. I know that the second i set the interface adaptor in the Controller VS comes nagging that it can not be converted to a "MyInterface" Class. Obviously i am doing something wrong. I can change the datatype that the controller expects to the "MyController" type but that would completely ruin the whole idea of flexibillity. I am hoping someone sees what i am trying to do and can point out where i made the thinking error.
View 6 Replies
