C# - Multi-level Interface Inheritance With .NET And COM Interop
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
ADVERTISEMENT
Jun 18, 2010
Let's say I have 2 interfaces defined like so:
public interface ISkuItem
{
public string SKU { get; set; }
}
[Code]....
VB.NET explicitly requires you to add Implements IInterfaceName.PropertyName after each property that gets implemented whereas C# simply uses regions to indicate which properties and methods belong to the interface.
Interestingly in VB.NET, on the SKU property, I can specify either Implements ISkuItem.SKU or Implements ICartItem.SKU. Although the template built by VS defaults to ISkuItem, I can also specify ICartItem if I want. Oddly, because C# only uses regions to block out inherited properties, it seems that I can't explicitly specify the implementing interface of SKU in C# like I can in VB.NET.
My question is: Is there any importance behind being able to specify one interface or another to implement properites in VB.NET, and if so, is there a way to mimic this functionality in C#? Furthermore, what is the effect of specifying one interface over another when implementing properites?
View 3 Replies
Apr 19, 2012
I've got a form with a listbox on it.In a second form I inherit the complete first form. But when I try to use that listbox in the second form with e.g.Index = LstWoodshop.FindString (Order(0))(where LstWoodshop is that inherited Listbox) I get the error message:'LstWood shop' is not declared. It may be inaccessible due to its protection level.What or where can I change this setting so that this listbox on form 1 is also available/accessible on form 2?
View 5 Replies
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
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
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
Apr 6, 2010
In my first application I need to create a multi-level "IF" statement and I am a little lost on how to proceed. The idea is to do figure out an estimate on costs based on the quantity of products being sold. I can do this in Excel, but the VB code escapes me.
So I'll show you in psuedo code what I want to do.
IF comboBoxA = 1 and comboBoxB = 1 then
value X
IF comboBoxA = 2 and comboBoxB = 1 then
value X
If comboBoxA > 3 and comboBoxB > 1 then
(comboxBoxA * costA) + (comboBoxB * costB) = Value X
I have another IF statement that will work off the calculations here. Haven't figured this one out yet, but I haven't gotten there yet in my form.
If Value X > Y Amount then
Offer product Z as a better idea
View 6 Replies
Dec 18, 2009
I want to make multi level side strip with some data as shown in figure below:
The first column could be labels (names) read from an array or a variable and the second column could be a value to that label read from a variable or array. The value of the last column will be assinged to the label or in the first column. for example:
Column1 (level1) Column2 (Level2) Column3 (Level3)
Area1 => Value => 5
8
Importance => 9
[Code].....
View 3 Replies
Aug 13, 2011
I can create a Custom UserControl with simple properties (Integer, String, etc) and have those properties show up in the Property Panel. I can also create a Custom UserControl with properties like Size, Rectangle, etc and the properties will show up as an expandable item in the Property Panel (click on the '+' and the Size expands to Width & Height).
Is it possible to create properties with my own custom structure? e.g. Property 'Message' expands to Text, ForeColor, BackColor, Blink etc. I have tried creating a property that references a simple class or structure with containing the properties representing my custom structure but in the Property Panel the property is greyed out and cannot be expanded or modified.
View 1 Replies
Oct 25, 2010
The first list box contains the project name. Based on whatever is selected in the Projects list box, the 2nd list box is generated with Custodian names associated with that project. I am having problems generating the 3rd list box. This holds the data sources associated with whatever is selected in the 2nd list box (Custodians)
View 1 Replies
Aug 25, 2009
With the following code I only can add until second level node... If wan to add more level in child node?? I want to add child node to "UOM" node??
TreeView1.Nodes.Add("Maintenance", "Maintenance")
TreeView1.Nodes("Maintenance").Nodes.Add("2", "Item Group")
TreeView1.Nodes("Maintenance").Nodes.Add("3", "UOM")
View 4 Replies
Jul 30, 2009
I'm using an interop COM assembly in my 1.1 VB.NET code, and when I try to set a property of a class, I get an InvalidCastException with the message "QueryInterface for Interface ¦ failed."
View 1 Replies
Apr 18, 2011
Is it possible to get the MouseWheel event from an Interoped ActiveX Control?
I have a DXF Viewer (with measure) control I wrote in VB6 that is quite frankly... Huge. It would take an inordinate amount of time to rewrite the whole thing and supporting tools in VB.NET. The MouseWheel event is used to Zoom in and Out. The control has a MouseWheel_Input() method to accept MouseWheel data from the host.
I added all the VB6 Mouse events, the Enabled Property, and The ActiveControl Property in VB6. Recompiled and registered the control on my VB.NET development machine. Added the control to my new VB.NET project and verified it has a focus method.
View 1 Replies
Feb 22, 2012
I've got this code
Public Class Form1
Dim m_listener As HttpListener = Nothing
Dim m_asyncCount As Integer = 0
[code].....
View 8 Replies
Feb 27, 2009
Ive been working on creating a side scroller game, and the back color of my pictureboxes needs to go. when transparent, it shows through the program and onto whatever is active in your Windows os(usually Visual studios).
I am trying to rip pixel color off of the background image picturebox( the level), and replace parts of the character picture box that show transparency with the level art. there may be poor logic in my code?
Heres my code:
Dim newImage As Bitmap = New Bitmap(PictureBox1.Image)
Dim backImage As Bitmap = New Bitmap(PictureBox2.Image)
Dim ximg As Bitmap = New Bitmap(PictureBox3.Image)
[code]....
not the best idea, but all i get is one color for all the level pixels placed in the new image, which is odd. any poor logic you see in this code that could allow the newImage.setPixel not to be 1 color? when i breakpoint, it is recieving different colors from the backimage.getpixel, but only putting one shade on for setpixel somehow. im not going for an accurate color read from the background yet, just wondering why im getting 1 pixel color for the whole picturebox background when being changed.
View 1 Replies
Dec 14, 2009
May i know how to change my below login code to support for multi access level login? So that i can differentiate between manager and normal employees login so that i can enable or disable certain features for different department? I have the below code that can serve as a basic login.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'login code can work
conn.Open()[code]......
View 5 Replies
May 10, 2009
I have been trying to use vb2008 to automatically update CustomDocumentProperties fields that I have set up within a pro-forma document. I can load the Word application and word document without problems.I want to update the CustomDocumentProperties fields with data read from a dB. To do this I am assuming that I need to iterate through the CustomDocumentProperties fields within the word document and when one is "found" that matches the data I wish to merge then assign the dB value to the field.The problem is that I am getting an exception error when I try to reference the document customdocumentproperties
"Error : Unable to cast the COM object of type 'System._ComObject' to interface type 'Microsoft.Office.Interop.Word.CustomProperties'. ...... "
my code looks like;
Dim WordApp As Word._Application
Dim odoc As Word._Document
Dim BContinue As Boolean = True
[code].....
View 2 Replies
Apr 1, 2012
I am creating an Excel add-in written in VB.NET. I would like to bind KeyDown and KeyUp events to the spreadsheet to record when the user presses and releases the arrow keys while navigating the spreadsheetIdeally, these events would be built into Excel alongside the native SheetActivate and SheetSelectionChange events, for example. Alas, they are not.
View 1 Replies
Jan 6, 2010
In Visual Basic 2008, there's two different ways that I know of to accomplish the same thing:The Dim on the member level:
Dim counter1 as integer = 0
Dim counter2 as integer = 180
Public Sub SampleSub1()
[code].....
View 1 Replies
Mar 18, 2011
I have created a simple program which uses a two tier structure of SQL Tables.At the top level, one record holds the date of the activities and linked to it using its primary key as a foreign key, three subordinate tables hold time stamped records.The issue I have been unable to solve is that before adding any of the lower level records for a given date, a newly added top level record must be saved to the database.Doing this manually is simple - but can I rely on my users to remember to do this before they start plugging in the lower level data?I thought not, so I am looking to save the top level automatically.I've failed miserably but I refuse to believe that it's not possible.
View 14 Replies
Feb 12, 2011
I have multiple level of For Each and in each level, i have a Linq that is the 'In' criteria as in:
[Code]....
It will go inside each for (because the value is not nothing), however, it will only loop (next) in the very inner 'For Each t In tFor'. After it is finish inner loops, the outer Fors' or Next will not execute... even thought there are more than one values in that 'In'... like 'sFor' or 'fFor'. i've noticed while debuging, while break at the for (for example 'sFor', before stepping in), i get the error message:
"Enumeration yielded no results" when i expand the result for that variable and it will not step into it. but if i do not expand the result, it will step in. It seem that some how, once an element is accessed for that 'In' collection, it breaks (meaning does not loop for the rest of the elements) the next for that collection is this a bug or am i missing something in Linq? BTW: i believe it has something to do with the SqlDataReader in the Linq. I'm working with IAsyncResult.
View 5 Replies
Feb 10, 2010
I'm adding multi-threading facilities for the first time. I have a function that is wrapped to be run in a separated thread. This function retrieves data (text) from a combobox and it works for sure without multi-threading.
When I call it as multi-threaded, I get the following error when I try to retrieve the data from the cmobobox: Cross-thread operation not valid: Control 'cmb1stBL' accessed from a thread other than the thread it was created on.
It looks like a restriction of thread-safety... I assume that the child thread cannot read from his parent, to make sure that he doesn't change his parent data. So how can I read the data from the combobox? Should I read the comoboxbox data before calling the child thread?
View 4 Replies
May 14, 2011
I have a need to build an app that will access about 10 websites and pass data to them, etc.I've read about something called multi-threading when searching Google. I've also seen people say that they use multiple browsers.Which route is better to use? I figure if you have to do some sort of multi-threading that you would access a single browser?
View 2 Replies
Aug 29, 2011
i want to write a small app which enables the user to burn some files on cd/dvd. Something like:
- Make an export from related DB Tables with informations
- Collect customers informations
- zip everything
-burn on cd (its a settlement related tool)
View 4 Replies
Nov 10, 2009
U0161 import a Platinum level Advisor .jar to use with this Platinum level product key.How I can get this and import it to continue my completion of setup of mysql download?From where I can download that file?To enable this application, please provide a MySQL Enterprise Product Key or your MySQL Enterprise credentials.
View 1 Replies
May 14, 2011
i have one project with multiples web services so i created various singleton class thinking in
performance. now i think create one singleton class and that have the instances of my webservices
[code...]
View 1 Replies
May 14, 2011
I have a need to build an app that will access about 10 websites and pass data to them, etc.I've read about something called multi-threading when searching Google. I've also seen people say that they use multiple browsers.Which route is better to use? I figure if you have to do some sort of multi-threading that you would access a single browser?Not sure which way I should approach this app.
View 2 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
