Interface Implementation In Partial Class?
Jul 16, 2009
I 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]....
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Jul 5, 2010
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] ......
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Feb 28, 2011
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.
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Apr 21, 2011
I have extended an Entity Framework 4 entity class with a calculated property in a partial class. This member is not available on the client to which the entities are exposed via WCF RIA Services.when using C# appears to be changing the extension of the partial class file from .cs to .shared.cs. I tried this with my VB.Net solution (.vb to .shared.vb) and got a long list of errors. I believe what happened is that the partial class lost its association with the entity on the client - it inherited from object rather than EntityObject.
My best guess is that this is related to the way that VB.Net handles namespaces.Each project has a 'Root Namespace' which is prepended to anything that is defined within a code file. C# has a 'Default Namespace'which is the namespace into which new types are placed by default - via a namespace statement within the file.The partial class is probably having the client namespace prepended to it which puts it into a different namespace than the entity with which it is associated on the server.Is there any means of extending an entity in such a way that those extensions are available on the client via WCF RIA Services and VB.Net?
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Jan 19, 2011
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.
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Feb 8, 2011
I need to implement the IBindableComponent to the the following code:
Public Class InfragisticsToolStripBindableButton
Inherits Infragistics.Win.UltraWinToolbars.ButtonTool
Implements IBindableComponent
[code].....
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May 21, 2010
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.
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Dec 25, 2009
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.
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Sep 11, 2010
This 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?
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Oct 16, 2009
How to implement explicit interface implementation in VB.NET?
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Jul 14, 2010
Is 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.
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Oct 27, 2009
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..
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Jan 9, 2010
I 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?
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Jan 11, 2011
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();
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Sep 12, 2009
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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Apr 20, 2009
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]...
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Jan 17, 2009
I have an interface class (IUser) which is the interface of class User. Now, i want to put these into an IList but am confused as to how i should declare the IList:Dim userList As IList(Of IUser) = New List(Of IUser) Dim userList As IList(Of User) = New List(Of User) Dim userList As IList(Of IUser) = New List(Of User) Dim userList As IList(Of User) = New List(Of IUser) when instantiating should you always use its implementation; and when using it as a type use its interface?
And when im creating a new user should i use: Dim myUser as IUser = new User?
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Mar 29, 2009
When you create a new asp.net page in VS 2008 and choose code behind, it also creates the typical aspx.vb or aspx.cs file to go along with it.
At the top of those files, VS names the 'Partial Class' name the file structure and/or name of the aspx file.
The question: Is there a best practice for this? Can I just use a single class name for all the pages in my application or perhaps a single directory instead of having to give each one a unique name?
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Nov 30, 2010
I would like to create a partial class for my form. I have a lot of events, and it gets messy, so I would like to break up sections into their own files. The problem: When I create a partial class of my form, say:
Partial Public Class Form1
End Class
Visual Studio decides I need another form for this partial class.
1. How do I create a partial class for a form?
2. If I cant do that, how can I break up all the events in my form into different files?
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Apr 21, 2010
How do I insert the partial class to be correct?
Imports System.Data
Imports System.Data.SqlClient
Partial Class
[code]....
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Apr 10, 2009
I am currently working on a project of "interpreting" C# into VB. The project involves adding images to a database, retrieving images from the database and presenting them in thumbnails. Right now I have the following Public Class with the Variable that needs to be assigned:
VB:
Imports System.Data
Imports System.Drawing
Imports System.IO
[code]....
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Aug 5, 2009
I have a textbox which is bounded to the typed dataset. If the user in the textbox &hit keydown, it should allow only numeric values with 2 decimal points and also it should not allow more than one "."(dot). I found many but all thats are using textbox event
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Sep 29, 2011
I am testing custom data validation with partial classes. It is a Windows Form Entity Framework application .In the partial class file (time.vb) the code is:[code]What is wrong with my code? How can I handle the exception message in the main form (thrwon by the OnDataFundChanging event)?
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Sep 9, 2011
I am trying to write some unit tests on a class that looks like this, using Moq [code] the parameterized constructor is private or internal one of the two methods relies on the result of the other.I want to check that when GetThisOrThat is called with a value, it actually calls GetThis. But I also want to mock GetThis so that it returns a specific well-known value.To me this is an example of Partial Mocking, where we create a Mock based on a class, passing the parameters for the constructor. The problem here is that there is no public constructor, and therefore, Moq can not call it..I tried using the Accessors generated by Visual Studio for MSTest, and use those accessors for the mocking, and this is what I came up with [code]
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Oct 7, 2011
I have recently come across some code that has the following. First there is a Interface with the following function Function Validate() As Boolean. That interface is then implemented in the an 'ABSTRACT' class like this.
Public MustOverride Overloads Function Validate() As Boolean Implements IBusinessEntity.Validate
Question 1: Why use Overloads in the Abstract class implementation.
Question 2: The Abstract class is then inherited into a class (TestClass). In TestClass the Validate function is implemented as follows Public Overloads Overrides Function Validate() As Boolean. I understand the Overrides keyword is to insure that this is the version of the Validate that you want called and not the Abstract class version but why again use the keyword Overloads?
From what I understand you can overload a constructor of a class by simply changing the constructor signature. Also, you overload Methods and Properties of a class by using the Keyword Overloads. But why do it when your implementing an Interface method, or an Abstract Class method that's inherited.
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Nov 12, 2010
I am trying to implement transactions across multiple TableAdapters in VB.NET (using Visual Studio 2010) by extending the partial class as described in the following examples:
http://blah.winsmarts.com/2006/06/18/the-definitive-tableadapters--transactions-blog-post.aspx
madprops.org/blog/typed-datasets-and-sqltransaction/
stackoverflow.com/questions/2342289/net-tableadapter-to-dataadapter
However, when I attempt to expose any of the private fields created by the designer they are underlined in the editor with the following error:
'_adapter' is not declared. It may be inaccessible due to its protection
level.
Searching this site as well as google has not revealed anything useful, but perhpas I'm searching the wrong keywords.
Here is the code in MyDataset.vb
Partial Public Class MyTableAdapter
Public Property MyTransaction() As SqlTransaction
Get
[code]....
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May 31, 2012
I am using Linq to Sql that generated a data contract for a table. I have a date field in that table which is a non-nullable field. I need to override the auto generated property of the date field to return a specific value, something like [code]Is it possible to override an autogenerated property in the designer.vb file using a partial class? I dont want to create a new property as it is currently being accessed in n number of places and I dont want to change it in every place.
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Mar 18, 2010
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]...
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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.
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Jan 27, 2010
I am instantiating a form object in my code behind the dataset just to access some form level variables and to occasionally set a label in the navigator bar. Recently in the b2 Team version of VS2010 there are some strange errors thrown in the immediate window and then I'm tossed out of debug mode and back into the IDE. This code has been operating for some time in this project without this behavior. A team member has just reproduced the behavior in his development machine also.The error that starts the shutdown of the debug instance is this: Control accessed from a thread other than the thread it was created on.
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