Yesterday I started my first DLL project which is for ArabicMessageBox that will allow arabic programmers to display there message in totally Arabic message.My project contain one Form only, and the basic code that I use is:
Public Overridable Function Show(ByVal APrompt As String) As MsgBoxResult
mLoad(APrompt, MsgBoxStyle.OkOnly, "")
Me.ShowDialog()
[code]....
I placed this checkbox named owner on my form. When i build the project i got the error as
Quote: 'owner' conflicts with property 'owner' in the base class 'Form' and should be declared 'Shadows'
[Code]...
Warning1property 'Events' shadows an overloadable member declared in the base class 'MarshalByValueComponent'. If you want to overload the base method, this method must be declared 'Overloads'.
<Global.System.Diagnostics.DebuggerNonUserCodeAttribute(), _
Global.System.ComponentModel.Browsable(false), _
Global.System.ComponentModel.DesignerSerializationVisibility(Global.System.ComponentModel.De
[code].....
I am converting an application from vb.net 2003 to 2005. I got the following warning and need help how to resolve it. withEvents variable 'PreviousPage' conflicts with property 'PreviousPage' in the base class 'Page' and should be declared 'Shadows'
View 1 RepliesWhat does this error mean? I havent modified anything in the designer code, but its giving me an error? WithEvents variable 'Move' conflicts with event 'Move' in the base class 'Control' and should be declared 'Shadows'. The error relates to Friend WithEvents Move As System.Windows.Forms.DataGridViewCheckBoxColumn
View 1 RepliesIn 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]....
how variables declared with protected access in a base class are used to implement inheritance.
View 1 RepliesBackground:I have a base class and several inherited derived classes. The derived classes don't always need to have the same properties. If any properties are shared among the derived classes, those properties would live at the base class level ('Contents', for example).Similarly, GoodDocument below has 'GoodThings' but would not want/need to have 'BadThings'.I want to treat instances of both 'GoodDocument' and 'BadDocument' as type 'Document'
public mustinherit class Document
public property Contents as string
public sub new()...
[code]....
In re-engineering a windows forms application, I find that a lot of code-behind in the various form classes is duplicative and I'm trying to centralize as many procedures as possible into a base class which can be inherited and used by the subclassed forms.
This process seems to be going well and is making the code in my subclasses much simpler and hopefully easier to maintain, but I'm not sure where to draw the line between leaving code in the subclasses and engineering for generic resusability and moving it to the base class.
Specifically, in some subclasses I have code which manipulates variables and objects specific to the subclass, and although I could move the code-behind into the base class, the base class code references specific objects which are needed to compile. For example, each subclass manipulates a databound datagridview and form detail controls which allows the user to select between multi-record and detailed single-record views of a datatable.
In Visual Basic 2008 do I need to declare dummy data objects in the base class so that the base class will compile? Or is there a way to indicate that the data objects will be provided by the subclass?
when we have a method of a derived class implementing a method of an interface which is already implemented in the base class, the compiler throws a warning (by default). when i see a warning i will try to erase it and the only way to erase this warning is to mess with the settings of the compiler hence i hope that there is a way to declare "how" a method implements an interface's method. by this i meant that we should be able to declare overridable, overrides and shadows for the implements keyword. hence if we declare overridable-implement for a method of a base class implementing an interface's method, the compiler should give no warnings when we override this implementation (re-implementing in a derived class). Similarly, if the method of the base class implementing an itnerface's method was not declared as ovveridable-implement, the derived class should be able to Shadow the implementation example code which flags unnecessary warning:
[Code]...
I have put this code in the global form Inherits System.Windows.Forms.Form. And then in the form that will inherit this from the global Inherits MenuStrip. "MenuStrip" is what the global form is called. But keep getting this error: Error1Base class 'MenuStrip' specified for class 'Lesson2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types.
View 5 RepliesI want to be able have the class autofire a function when it is first declared. In my example it would be to load from a file all the constant variables for use in the program.
View 4 Replies I realize that this is a very basic question, but it's been a long time since I've played with VB. Why can't I call the Synch() Sub/Function in my CMMS_SCAD_CLASS class from my Main module? I get the following compile-time error:
'Synch' is not a member of 'ConsoleApplication1.CMMS_SCADA_CLASS.'
Main class:
HTML
Module Main
Sub Main()
Dim meterClass As New CMMS_SCADA_CLASS()
[Code]....
I have a base class foo that will be used in multiple child classes of similar but slightly different function:
Public MustInherit Class foo
Public Function bar1() as Something
''// Perfectly OK to change what this method does
[code]....
How do I get the compiler to generate an error when bar2() is overridden by a child class?
I've been creating short test apps repeatedly to try to understand some of the concepts in VB.NET.For the most part it has been illuminating.I read Bucky's .NET knowlegebase tutorial on passing objects as parameters to newly created forms. He shows how to create a new class that inherits from the base form class and define a New() method with parameters Extending the concept I thought about doing the same thing with a form that was created at design-time (In this case Form2).
[Code]...
I knew VB.net is very weird when talking about shadows and overloads, but this this I'm completely baffled.I'm working with a model similar to the following one. Parent class:
Public Class Base
Function F() As String
Return "F() in Base Class"
End Function
[code]....
I'm developing a software that handles very specific regional standards. In one part of the country they have different standards for entering this data than they do in other parts of the country. In fact there are hundreds or thousands of possible configurations that would be best in various regions.
The solution I've come up with is to write a program that can load different control configurations with the supporting code to its main form at runtime. I do not know how to accomplish this. Would I use visual inheritance at runtime? Would I use a plugin system? I just need to potentially allow a power user to design thier own interface or to modify an existing interface to better suit thier needs.
Edit: Is there a way to define the base class of a form at runtime? Could I create user controls in a plugin and pass them in to the host program?
I created an enumeration in a class library... and compiled it into a dll
Public Enum TestEnum
x = 0
End Enum
I then imported this reference to a windows form project as a referenced dll Public Class Form1 Dim mytestenum As TestPublicEnum.TestEnum Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[Code]...
I happen to have these common procedures which I want to be used in my forms and usercontrols, with the form I can put those procedures in the base form which is being inherited but I happen to have a need to use those same procedures in my usercontrols, is there a way that I can have a common base class that I can use both for my form and usercontrol? I haven't used yet a base usercontrol since my usercontrols will not look the same so I have to put those procedures in each one of them and I find it rather cumbersome.
View 8 RepliesWhen I do this
Public Class cInherits : Inherits Panel
I get this: Base class 'System.Windows.Forms.Panel' specified for class 'MenuButton' cannot be different from the base class 'System.Windows.Forms.UserControl' of one of its other partial types.
How do I inherit?
I am making a TabStrip control to hold a number of tabs just like TabControl, but only with the tabs, no page. The control has a "Tabs Collection", which stores a list of "Tab" class. "Tab" is not inherited from Control, but each tab has its events. So when the user add a "Tab" in the "Tabs Collection", each "Tab" instance should have a (Name) identifier, which user can access it in the code, and with WithEvents keyword so users can add event handlers to each "Tab". The expected out come should similar to this:
Friend TabStrip1 As TabStrip
Friend WithEvents t1 As Tab
...
Me.TabStrip1.Tabs.Add(t1)
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I have a database that holds information about a particular job. One of those things is a customerID. CustomerID links to another table containing customer details. I have a combo box attached to a custom object that holds customerID as the valuemember and CustomerName as the displaymember.The JobDetails holds the customerID info. How do I set the default selection in the combobox based on the ValueMember of the combo box?
View 2 RepliesWhen trying to compile my newly created ClassLibrary class 'Validator' that validates entries made into TextBoxs or MaskedTextBoxs, I get the following error:
Warning 1 Namespace or type specified in the Imports 'System.Windows.Forms' 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. C:Users erryDocumentsVisual Studio 2008ProjectsMillerClassLibMillerClassLibValidator.vb 1 9 MillerClassLib.
Following is the first part of code in the class:
Imports
System.Windows.Forms
Public
Class Validator
[code]....
What can I do to resolve this problem? The classes in this class library will be used to validate forms data input in a number of varied projects.
Base class has one field to hold numeric balance value. With 2 methods that accept arguments for adding and subtracting the new input calculating new balance. Sub class has four fields dates, transaction, memo and amount.I have a deposit form, and withdraw form. Each time one transaction is entered it creates an object with sub class fields, then adds to the account collection. My problem is not understanding how to call the deposit/withdraw method and pass the current transaction amount back to the base class to alculate the new balance. Does anyone have any links to information/tutorials on how to perform something like this? As you can see with my code I have tried various different approaches without any success.
[Code]...
Supose a base class
Public Class airplane
Private var_num_seats As Integer
Private var_num_engines As Integer
[code]....
Obviously, I don't wish that the class Glider has the method "start_engines" neither the property "num_engines". Otherwise, other child classes may have. How can I supress these property and method in child class, not just ignoring (if I can)?
I am trying to create a class in VB.NET which inherits a base abstract class and also implements an interface. The interface declares a string property called Description. The base class contains a string property called Description. The main class inherits the base class and implements the interface. The existence of the Description property in the base class fulfills the interface requirements. This works fine in C# but causes issues in VB.NET.
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This is another one of my "I think it's not possible but I need confirmation" questions.I have a base class for a bunch of child classes. Right now, this base class has a few common properties the children use, like Name. The base is an abstract class (MustInherit)Technically, this means that everytime a child class is instantiated, it lugs around, in memory, its own copy of Name. The thing is, Name is going to be a fixed value for all instances of a given child. I.e., Child1.Name will return "child_object1", and Child2.Name will return "child_object2".
View 1 RepliesSuppose I have piece of code like this:
Public Interface ISomething
....
End Interface
[code]....
I suspect I am being very silly here but I have the following setup
Class MustInherit myBaseClass
'some stuff
End Class
Class myInheritedClassA
[code]....
Running this results in the following error
Unhandled Exception: System.InvalidOperationException:
There was an error generating the XML document. --->
System.InvalidOperationException:
[code]....
is there any way of 'Widening' the inherited class to the base class so this would work?
EDIT:regarding XmlInclude(typeof inheritedClass), currently this method could potentially return a number of types of inherited class (i.e myInheritedClassA and myInheritedClassB) is it case of simply having to add each of the inheritedTypes in this tag?
warnings got me thinking about old issues that always goofed me up when I was writing more VB.NET code.One of them was the fact that the compiler didn't warn if you declared a Function but never did an explicit Return statement or assign to the Function name. Running Visual Studio 2008, I just made a small experimental project, and it seems as though the behavior has never been fixed.I created a Visual Basic Console application, with the following code:
Module MainModule
Sub Main()
Dim test As Boolean = TestWarning()[code].....
I also went into the Project Settings and turned On Option Strict and Option Explicit.I also set the Warning Configurations so that "Function/Operator with no return value" was set to Error.I compiled the project and got no warning, and no error on the TestWarning() Function. This seems like a great place to put a warning, because it will default to False, and you may have simply forgotten to do a return. C# will error without a return statement. I thought that VB.NET did the same thing with the "Function/Operator with no return value" configuration. Is this a bug, or is there something I'm missing?
Edit: Further Experimentation
Function TestWarning() As Boolean
If DateTime.Now.DayOfWeek = DayOfWeek.Monday Then
Return False[code].....
If, and nothing in the Else, there is also no Warning/Error. It will simply take the default, even though you likely intended (via programming style) to have an explicit return. In this case, I explicitly returned False (which is the default for Boolean), so it's likely a hidden bug that I should have returned True in the Else.