Overriding Properties Of A Subclass Of An Inherited Class?
Jun 7, 2012
I am trying to override a property of a subclass of an inherited base class. I've tried to simplify this code as much as possible but am not comfortable enough with my own abilities to simplify anything else without loosing the ability to understand an answer.The property propertyName in the otherClass is currently incorrect. I want to be able to override propertyName in baseClass with the propertyName in otherClass. Is this possible to accomplish?
Public Interface interfaceName
Interface iInterfacePropertyName
Enum enumName
[code].....
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Jun 3, 2009
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?
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Sep 13, 2010
Sorry if the title isn't very clear. This is a VB.NET (2010) question I have a superclass called "Device" which has a number of subclasses that inherit it. Some of those subclasses also have subclasses. In particular, I have a class called "TwinCatIntegerDevice" which inherits "TwinCatDevice" which inherits "Device."The relevant parts of Device look like this:
[Code]...
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Dec 29, 2010
I have a base form class that is providing a new property that looks Like this
Public Class BaseForm
Private _HappyTime As Boolean
Public Property HappyTime() As Boolean
[Code]....
Now when I inherit the BaseForm on a new form, the HappyTime property displays in the properties window as false, and is uneditable.
I've recreated this BaseForm and Inheriting Form in an entirely new soloution and, the HappyTime property is editable and works as expected. For some reason in the existing project (where these changes need to be made) it's not behaving properly.
Environment Information: .Net Framework 3.5, Visual Studio 2010, Win7 x64
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Jul 29, 2009
I created a custom datacolumn class which inherits from DataColumn and has 2 properties. I then successfully added this custom datacolumn to a datatable. When i try to access the properties through the datatable.columns(index).property, the properties i added are not listed. If i go back in the code to where i instantiate the custom datacolumn i can see the properties here, but not after its added to the datatable.
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Dec 3, 2008
Seems like you should be able to Suppress Properties in inherited classes. How do you do it?
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Jun 10, 2011
Suppose I have piece of code like this:
Public Interface ISomething
....
End Interface
[code]....
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Sep 25, 2009
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?
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Sep 17, 2010
I have a main class that has a Sub procedure with no implementation. Any derived class should override and implement this procedure, so I used MustOverride in the base class.
Now, any time this procedure is called, I need to set a specific Boolean variable to True at the beginning of the procedure and set it to False at the end.
Is there a way to avoid writing these two lines of code in procedure implementation of every single derived class? Can I set this value to True in the base class, then run procedure in the derived class and then set the value back in the base class?
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Mar 23, 2009
I am using visual inheritance and was wondering if there is a way to change the properties of inherited controls at design time, preferably in the form designer. If not, then in the designer code. I have my control declared as Public in the base class. I can access it in the child form code, but not in the form designer. Is this just not possible?
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Mar 30, 2009
i created a user control and inherited a textbox.is it possible to remove some of the inherited properties of the user control?like to Multi-Line, PasswordChar etc also at the Form Design, when selecting the user control, there's an arrow on the upper-right which i also want to remove.
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Jul 16, 2009
I've written my code to implement a new property and to set the content to this default text and grey the text whenever the textbox is empty, and to hide it when the user starts typing. This all works fine at runtime.[code]My question is this : If I place an instance of the control on a form, and set the DefaultText via the properties grid, why doesn't my Property Set code run?I'd expect the control on the form to show my new DefaultText in the control, but instead it remains blank. When I run the form it does display correctly, but just not at design time. I place a breakpoint in the DefaultText set property code and it simply doesn't run.
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Jun 2, 2009
I understand that inherited classes can't be converted from base classes. But is there any way to write a conversion sub, so that the base class gets assigned to MyBase, then extra properties are added?[code]...
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Oct 29, 2009
I'm trying to force an inherited class to use a custom attribute. I'm creating a class library where the user who wants to create an item will do so, but be forced to add an attribute (or visual studio will automatically add the default attribute) to their inherited class. Here is what I'm hoping to achieve:
BaseClass.vb:
<CustomAttribute(10)> _
Public Class BaseClass
End Class
MyClass.vb:
[Code]...
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Jan 12, 2010
Most of our code base is in VB.NET. I'm developing a project in C# that uses a lot of the assemblies from the VB.NET code.There are three relevant classes in VB.NET:
[Code]...
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Nov 3, 2011
I am trying to use a custom colour scheme for painting my menustrips, toolstrips etc. To do this, I am implementing a custom ToolStripProfessionalRenderer.
Normally i would simply set the renderer of each toolstrip etc. to a new instance of a ToolStripProfessionalRenderer instantaniated with a custom ColorTable i.e.
Dim myRenderer As ToolStripProfessionalRenderer = New ToolStripProfessionalRenderer(New MyColorTable)
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Aug 20, 2010
I did this code to see how the method overriding works;the code runs with a warning in the add method of the Class c2:
[Code]...
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Jul 31, 2010
i have a class named fdetails and i do not want any other class to inherit from this classCan i set it to not being inherited by another class. I would like to get the things done in the following 3 languages
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May 23, 2010
i have a class named fdetails and i do not want any other class to inherit from this classCan i set it to not being inherited by another class. I would like to get the things done in the following 3 languages
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Jul 5, 2010
bare with me during this silly example. :-) Let's say I have a class like this:
Public Class Animal
Public iLegs as int32 ' Number of legs
Public bWings as Boolean ' Wings? Yes/No
End Class
And another class that inherits the "Animal" class and adds one more property:
Public Class ScaryAnimal
Inherits Animal
Public iScariness as int32 ' 0-100, how scary is it?
End Class
Now, if I have an instance of "Animal" with some values in it, and I decide I want to cast it to a ScaryAnimal for some reason, how do I do that without having to create a new instance of "ScaryAnimal" and copy each property value?Basically I'm looking for a way to do this, without having to write the lines marked with '*** below:
[Code]...
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Nov 16, 2009
take a look at the following code:
[Code]...
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Nov 23, 2009
I have a copy function that I'd like to override in subclasses to return the type of the subclass. Here are my interfaces:
Public Interface IBase(Of T)
Function Copy() As T
End Interface
[Code]....
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Oct 14, 2011
I have two classes[code]...
How can I modify class1 in a sub in class2?
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May 19, 2010
The program below trhows an error in the line "mTable2 = mTable.Copy". The error is: "Unable to cast object of type 'System.Data.DataTable' to type InherintanceQuestion.InheritedTable". This is because mTables is an instance of the InheritedTable class which inherits a DataTable and mTable is a DataTable. So, is there any way I can create the mTable2 to the mTable.copy to the mTable.
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[code].....
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Jan 11, 2010
I'm having trouble with the definition of an inherited generic class. I have two base classes that are defined like this:[code]
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Feb 13, 2010
Is there a way to hide a method of a base class that has been inherited?Lets say the base class has the properties:
x
y
Height
Width
and the method
sub SpecialInstructions()
Now this class is inherited by some classes that either use the SpecialInstructions method or override it. But one class inherits it but cant make use of the method and therefore wants to hide it. I tried shadowing but it still seems that the method is visible ex
Private Shadows Sub SpecialInstructions()
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Dec 30, 2009
I have a class which inherits a form class, and just recently it's started acting strange. All of the controls on the form are locked, and I don't understand why. I can't edit the properties of any controls, or anything.
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Apr 5, 2011
Below is example code of what I want to do:
Public Class Test
Sub New()
Dim cool As New B
cool.Doit()
[code]....
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Feb 29, 2012
When I transfer my project to a server, I now get this error message. What does it mean and how do I fix it?
Server Error in '/HD' Application.
Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Could not load type 'HD._Default'.
Source Error:
Line 1: <%@ Page Language="vb" AutoEventWireup="false" CodeBehind="Default.aspx.vb" Inherits="HD._Default" %>
Line 2:
[Code]....
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Jul 10, 2009
I am wishing to emulate the auto code generation that happens when you derive from a class, such as Form, and declare the Public Sub New() constructor. When this happens the constructor will auto-generate code like the following:
Public Class MyInheritedForm
Inherits Form
Public Sub New()
[Code].....
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