I have a public interface. i have class that implements the interface, how do i make the implementation of interface members internal or private in the implementation class? If i declare an interface internal, how to implement that in an public class?
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I know that the MenuItem class contains an internal class named MenuItemData, which contains itself an internal member named onDrawItem. Given a MenuItem, I want to retrieve the object corresponding to the member onDrawItem. But all I manage to do is to get the FieldInfo, not the object itself.
Here is my code:
Dim obj As Object
Dim fi As FieldInfo
Dim item as System.Windows.Forms.MenuItem
Dim mType As System.Type
[Code] .....
When reaching the last line, I get an error saying something like that (it's traduced):
The field 'onDrawItem' défined in type 'System.Windows.Forms.MenuItem+MenuItemData' is not a field of the target object of type 'System.Windows.Forms.MenuItem. I don't know what object to pass to the GetValue function on the last line. My goal is to remove the base eventHandler of the menuItem, named DrawItem. See this post and the function RemoveClickEventin the accepted answer for a better understanding.
I need to implement the IBindableComponent to the the following code:
Public Class InfragisticsToolStripBindableButton
Inherits Infragistics.Win.UltraWinToolbars.ButtonTool
Implements IBindableComponent
[CODE]...
1 problem: Warning: event 'Disposed' conflicts with property 'Disposed' in the base class 'DisposableObject' and should be declared 'Shadows'
2 problem: Error: Class 'InfragisticsToolStripBindableButton' must implement 'Property Site As ISite' for interface 'System.ComponentModel.IComponent'. Implementing property must have matching 'ReadOnly' or 'WriteOnly' specifiers.
Why should I implement "IComponent" if I implement "IBindableComponent"?
3 problem: How should I override "Dispose", if it's already implemented in the base class, but is not virtual apparently.
I need to implement the IBindableComponent to the the following code:
Public Class InfragisticsToolStripBindableButton
Inherits Infragistics.Win.UltraWinToolbars.ButtonTool
Implements IBindableComponent
[code].....
What is the diference of using interfaces like ...I have an interface
Public Interface IProDataSource
Function read() As Integer
End Interface[co]....de
The only difference I have notice is that if the method is declare private it will be visible using the first approach only.
I have been reading about design patterns and application architecture and im told that I should program to an interface instead of implementation. This i understand. So I figured I would start with something small. Never programmed with an interface before. So I want to create an encryption program that will allow the user to select which method to encrypt it with, AES, DPAPI, etc. I started designing the Interface but I am unsure if I am doing this right. [Code] Also, when it comes to the DPAPI implementation, how is the client supposed to supply the Protection Scope? I didn't think this should be in the interface as it only applys to the DPAPI.
View 1 RepliesThis may seem like an obvious answer, but I can't seem to find an answer. I have this code in VB.NET[code]...
The problem with this is that in C#, it would seem you have to name the function the same as the interface function you are implementing. How can I call this method EncryptionVB instead of Encryption, but still implement the Encryption property?
How to implement explicit interface implementation in VB.NET?
View 3 RepliesIs there any way to include some kind of auto-generated comments as part of implementing an interface? Studio automatically fills the headers for the methods, can I auto-fill some sort of code comments at that same time? (to help remember what each interface method is supposed to do without looking at external documentation.) For example, if I could get the interface's XML Intellisense markup headers to copy from the interface down to the implementation's level.
View 3 RepliesI am reading a book (ASP.NET 3.5 Enterprise Application Development with Visual Studio 2008: Problem Design Solution, WROX)The source code is written in C#, but I am a VB guy, so I am giving it a try. Somewhere in the 2nd chapter, there is a Linq to Sql file used that is generated by drag&dropping the DB tables from the Database Explorer. Because some tables have the same type of fields, there is an interface generated called IENTBaseEntity. The writer says its a good practice to implement this interface in another partial class (not the designer.vb file!). The reason for this is that when the LinqToSql file is modified (and regenerated) the changes wont be lost.
In C# this solution is easy to do (i think), but in VB.Net I get an error, because the concerning properties in the LinqToSql file do not append the 'Implement IENTBaseEntity.Property' line. When I press [Enter] after the interface implementation line, VS generates other properties like this
Partial Public Class ENTUserAccount
Implements IENTBaseEntity '--->This line results in the error
' This is not the way it should be
Public Property InsertDate1() As Date Implements IENTBaseEntity.InsertDate
Get
End Get
[code]....
Private Sub ActivateMe(ByVal active As Boolean) Implements IGraphicControl .ActivateMe compiles.How is possible in VB.NET? A private method can be an interface implementation. VB.NET... a lot of compliments to this language and IDE..
View 6 RepliesI have a WPF VB.NET project in Visual Studio 2008. For some reason, Visual Studio thinks that it needs to add anImports MS.Internal.Xaml.Builtinsto every auto-generated XAML partial class (= the nameOfXamlFile.g.vb files), resulting in the following warning:warning BC40056: Namespace or type specified in the Imports 'MS.Internal.Xaml.Builtins' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.I can remove the Imports line, but, since this is an auto-generated file, it reappears every time that the project is rebuilt.
View 1 RepliesI have a C# interface defined as so:
public interface IMenuSecurityService
{
void SetSecurityFlags(List<MenuItem> items);
}
I need to implement this interface in a VB.Net class. When I implement the SetSecurityFlags method with the items parameter passed ByVal, it compiles.
Public Sub SetSecurityFlags(ByVal items As List(Of L1.Common.Model.MenuItem)) Implements IMenuSecurityService.SetSecurityFlags
' do some work
End Sub
When I try to implement it with the items parameter passed ByRef, I get the following compiler error: Class 'UserRights' must implement 'Sub SetSecurityFlags(items As System.Collections.Generic.List(Of Model.MenuItem))' for interface
Public Sub SetSecurityFlags(ByRef items As List(Of L1.Common.Model.MenuItem)) Implements IMenuSecurityService.SetSecurityFlags
' do some work
End Sub
I can't seem to figure this one out. Does VB.Net not support this or am I doing something wrong?
In Visual Studio, when you right-click a method call, you go to the implementation of that method inside a class except if you access this method through an interface: in that case you go to the interface method not to the actual implementation.Is there a way / tips (key shortcut or anything) to access this actual implementation ? Otherwise you are stuck to add some comment just to remember where you did implement it that's really not productive and error prone !
Update: interesting answers but I'm not really satisfied because all are cumbersome. I will give a precise example:
IInterface iInterface = someObject;
iInterface.someMethod();
In the code below, when I use the same interface with O in the Class declaration line and the Inherits line, I then get a compiler error when I access the interfaces Year member in both the properties. It says " 'Year' is not a member of 'IRegionYear'." I get the same thing if I use the same class with each Of.
I don't get this error when the interface or class entered for both Of clauses are different.
Interface IRegionYear
ReadOnly Property Year() As Integer
End Interface
MustInherit Class RegionYears(Of IRegionYear)
[Code] ......
in VB.NET you implement an interface like this...
Sub SomeInterfaceMember()
Implements ISomeInterface.SomeInterfaceMember
End Sub
while in C# you do it explicitly like this (which can only be called via the interface)...
void ISomeInterface.SomeInterfaceMember(){}
or more simply, implicitly like this...void SomeInterfaceMember(){} // Note the name matches the interface member However, regarding VB, I can also do this...
Sub SomeRandomMemberName()
Implements ISomeInterface.SomeInterfaceMember
End Sub
In other words, the method that handles the implementation can have a completely different name than the interface's member name.I'm just wondering if there's something similar to this in C#. (Yes, I know I can simply do an explicit interface, then access it via another 'wrapper' member with a different name that simply delegates to it, but in VB.NET?
I am creating an xlsx reader / writer for my application (based on OpenXML SDK 2.0). I want to read xlsx files and store the data contained in each row in a DTO/PONO. Further I want to read the xlsx file and then modify it and save it.Now my problem is not with the OpenXML SDK, I can do what I need to do.My problem is on how to structure my components. Specifically I have problems with the polymorphism at the lowest level of a Spreadsheet, the cell.A cell in Excel/OpenXML can have different types of data associated with it. Like a Time, Date, Number, Text or Formula. These different type need to be handled differently when read/written from/to a spreadsheet.I decided to have a common interface for all subtypes like TextCell, NumberCell, DateCell etc.Now when I read the cell from the spreadsheet the Method/Factory can decide which type of cell to create.
Now because the cell is an abstract from the real implementation it does not know / does not need to know of what type it is. For writing / modifying the cell I solve this problem by calling .write(ICellWriter) on the cell I want to persist. As the cell itself knows what type of data it contains, it knows which method of ICellWriter it needs to call (static polymorpism).Writing to the xlsx file is no problem. My problem is, how do I get the data out of my cell into my DTO/PONO without resorting to type checking -> If TypeOf variable is ClassX then doesomething End If. As Methods / Properties have to have different Signatures and differentiating by only using a different return type is not allowed.The holder (collection, in this case a row of a table/spreadsheet) of the objects (refering to the cells) does not know the concrete implementations. So for writing a cell I pass it a Cellwriter. This Cellwriter has overloaded methods like Write(num as Integer), Write(text as String), Write(datum as Date). The cell object that gets this passed to it then calls the Write() method with the data type it holds. This works, as no return value is passed back.After some thinking about the problem I came to realize that it's not possible without reflection or knowledge of what type of cell I am expecting. Basically I was trying to recreate a spreadsheet or something with similar functionality and way too abstract/configurable for my needs.
I am comparing an alternative Dispose pattern to VS2005's default implementation. In doing the comparison I have found several uncertainties with the default pattern which have raised a handful of questions related to sub-class implementations and object Finalization.
[Code]...
This is a challenging one that got me stumped while I was coding today. Suppose I am running the Sub Test1() and Test2() and would like to print out the value of the Shadows method of the instance of the object I am passing in to TestCall() (see below - it is clearer) using the following restrictions:
Can't change the contents of Class A, B, and C
Can't change Sub Test1() and Sub Test2()
TestCall() can't have an if, select case etc. statement that tries to figure out the type
[code].....
I read somewhere that interfaces can have member variables.Static final constants only, can use them without qualification in classes that implement the interface. On the other paw, these unqualified names pollute the namespace. You can use them and it is not obvious where they are coming from since the qualification is optional.
View 3 RepliesI have an Interface defined like this:
Public Interface ISegment
''' <value>
''' The offset where the span begins
'''</value>
[code]....
The problem is that when I try to use the interface in another class, it tells me that Offset and Length are not members of ISegment. Clearly they are. Here is the code that uses the interface
Public Sub UpdateSegmentListOnDocumentChange(Of ISegment)(ByVal list As List(Of ISegment), ByVal e As DocumentEventArgs) Implements IDocument.UpdateSegmentListOnDocumentChange
[code]....
Okay this is a bit of a noobish question, but I ran across this today and it somewhat puzzles me WHY it would be this way.
Consider the following structure
Public Class Employee
Implements IPerson
Private _MyManager As Manager
[Code].....
Here is my question: I am wanting to have every person implement the IPerson interface, whether they are an employee, boss, or manager. However, they each have an attribute that refers to their leader (employees have a manager, managers have a boss, etc). Each implementation of their leader could be potentially differnt other than they fact that they implement the IAuthorityFigure interface. I am wanting to have the IPerson interface have a property for the IAuthorityFigure, but it throws a compiler error for me when I implement this b/c the IAuthorityFigure is not the same type as Boss or Manager (even though they implement the interface).
So I've been doing some research on the singleton factory design pattern, and I am wondering if my example implementation is correct (warning I did get carried away creating animals):
[Code]...
Is it possible to have an internal XML dataset within a VB 08 program I ask because we at present have the program load an external XML on startup, but i would prefer this to be internal withing the program to stop other editing the XML file.
View 6 Replieshow do I overcome it? I have created a class and compiled into .dll This code
[Code]...
In Visual Studio 2008, if I do this:
[Code]....
Does anyone here know how to get the above to work WITHOUT warnings being generated?
In the following code i get a warning at line 59:Warning 1: Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated.and.. At line 78 I get this Warning:
Warning 2 Property 'SelectedCustomer' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used.
The program compiles and runs well, but i cant' undesrtand the reason for these warnings. Any Idea ?
1: Public Class Form1
2:
3: 'Form level members
4: Private objCustomers As New ArrayList
[code]....
Cannot appear to be able to get this function to not have the above error.Private Function GetIncidentActions(ByVal FromAgentID As Integer, ByVal ToAgentID As Integer, ByVal incidentAction As Integer, ByVal ActionDate As Date) As String
[Code]...
I'm "cloning" objects in my code. For instance: objClone = objOriginal My question is: Does the assignment operator in VB.NET 1.1 do a member-by-member copy of the objOriginal to objClone or does objClone simply point as a reference to memory referenced by objOriginal?
View 3 Repliesi changed a class variable to shared so i can access it in all instances of the class, but it caused an error. what is causing this, and how can i fix it?
Private
Shared img As Bitmap
Me
.img = bgImage
