Dispose Method - Why Class Destructor Not Being Called
Jun 22, 2011
I have a class that has a destructor and a Dispose method (I also inherit IDisposable). Why is it that the only time my destructor gets called is when I call GC.Collect()?
I've noticed in that in C++ when you create a class you can have constructors and destructors.I've found that in VB you can have a constructor using:
Public sub new()
To initiate member variables.But I am confusted about destructors.Are they placed within the body of the class definition?How are they used in inherited class?
How do I force the Visual Studio compiler to generate an error when a required method is not being called in the constructor of a child class? Like when you edit the form designer code, the compiler complains when InitializeComponent()isn't the first call in the constructor of a form. Is this even possible in VB.NET?
I have a large problem with inheritance in vb.net. The problem is the following:
I have 2 forms => frmBase and frmChild
In frmBase i want to create a method Called StartWorking() and i want frmChild to inherit this method.
But here is the tricky thing: when frmChild.StartWorking is called i would like the following => without calling MyBase.StartWorking()
I want frmBase.StartWorking() to be executed first and after a test in frmBase.StartWorking if blnValue is true then frmChild.StartWorking has to be activated. if blnValue is false that frmChild.StartWorking cannot be activated.
If I have a class that inherits another class in which there are objects that are disposed in the dispose() procedure, do I use mybase.dispose? ex Class A inherits Class B. [code]
When is it appropriate to apply the dispose method to controls?For example in a form that has five group boxes, once the first group box is used to gather user entries and is no longer needed, is it worth it to apply the dispose method to the first group box? Is it needed for local variables, for example a StringBuilder used within a private function which is only used while the function is executing?
I was experimenting with ways to get rid of some memory leaks within my application the other day when I realized that I know virtually nothing about cleaning up my resources. I did some research, and hoped that just calling the .dispose() would solve all of my problems. We have a table in our database that contains about 65,000 records. Obviously when I fill my dataset from the dataadapter, the memory usage can get pretty high. When I called the dispose method on the dataset, I was surprised to find out that NONE of the memory got released.
I have Overloaded the Dispose method of System.Windows.Forms.Form Class in which I have written some extra code which I need to execute when object of Form Disposes. But when I create the object of Form in 'Using' statement, the 'End Using, statement do not execute my overloaded Dispose method. What should I do?
Consider a MyForm class that contains a shadowed implementation of Show(). It also contains a CreateForm() method, which accepts an instance of the form and calls the shadowed sub:
Is there any sense to set custom object to null(Nothing in VB.NET) in the Dispose() method?Could this prevent memory leaks or it's useless?!Let's consider two examples:
public class Foo : IDisposable { private Bar bar; // standard custom .NET object public Foo(Bar bar) {
I have 2 question, hope somebody give me an explanation: 1. Should a local variable call dispose method and set to nothing? 2. If some method have an arguments which it is a ByVal argument, it means a method create a new object? But If it is a ByRef argument, it means a method don't create a new object?
From my understanding, .Net will pool SqlConnection objects where the Connection String is the same by default. Will the connection still be pooled if I call the Dispose method? This question is asked under the context of an ASP .Net application that at times makes many hits to the database in a single PageLoad event. I want the connections to be pooled, but would like confirmation that Closing and Disposing of the connection once the data operation is complete does not interfere with .Net's handling of the connection pool.
I know this is working as when the item is clicked I get a javascript popup so I would assume the problem is not here.
Now my Javascript:
function DeleteTicket(ticketID) { var answer = confirm("Do you really want to delete this task?")
[Code].....
EDIT: Could anything in the web.config file be preventing page methods from executing? I have just noticed this happening with a completely seperate web method and have checked the integers being passed into the javascript with an alert() and they are all valid
I have a class which i realized will not always correctly instantiate and as a quick fix, i figured i'd subclass it and shadow a few methods so that the program can continue to run without exploding. When i run the software, calls to the methods resolve to the base's implementations and not the subclass. I'm using VB.NET with .NET 2.0. Here is an example of what i'm trying to do[code]....
When I put a breakpoint in a method I'm calling from a lambda expression, the breakpoint is never hit. When I move the method call outside the lambda, the breakpoint hits.
For example:
Function IncrementAll(ByVal items As IEnumerable(Of Integer)) As IEnumerable(Of Integer) Return items.Select(Function(i) Increment(i)) End Function
[Code]....
If I call IncrementAll, the breakpoint in Increment does not get hit. Is there a way to make VS 2008 stop on these breakpoints? I hate the thought of rewriting all my LINQ into loops just for debugging.
I am trying to use the AAA syntax in Rhino Mocks with VB.Net to validate that a method was called only one time. I can't seem to get it right. With this code, if the repository is called twice, it returns nothing on the second call, and the test passes. I would have expected the test to fail when VerifyAllExpectations was called.
<TestMethod()> Public Sub GetDataCallsRepositoryOneTime() Dim repository As IDataRepository = MockRepository.GenerateMock(Of IDataRepository)()
I create a UserControl (TableWithFilter.xaml) with a dependency property (source). The UserControl is a Table with a source property for the different items. I created the XAML and set the source property via the XAML Binding. So far so good.
But if the value of the dependency property is changed, the defined callback method is not called. Therefore I cannot update the entries in my table. Has anyone an idea why the callback method is not called?
Here is the definition of my property in the class "TableWithFilter":
Public Shared ReadOnly SourceProperty As DependencyProperty = _ DependencyProperty.Register("Source", GetType(List(Of TableViewItem)), GetType(TableWithFilter), _
[Code]....
If the attribute "ContentList" is changed I expet that the "ChangeSource" method in the TableWithFilder class is called. But this is not the case. After I changed the ContentList attribute, I Raise the following Event:
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("ContentList"))
I have a set of nested classes built inside a main class called MainClass. This is a class library project, the end-user will be using the MainClass by referencing.
I want to add a user login functionality at the creation point of the class. So that if the login fails, the entire class is inaccessible to the user. I have the following code
I'm trying to work out whether every Class in an Inheritance chain needs an explicit Dispose(disposing As Boolean) method or, if a given Class has neither managed nor unmanaged resources to dispose of, it can be skipped for that Class - even if a latterClass does require a Dispose method to dispose of mananaged or unmnaged resources?
Here's two examples: Public Class BaseClass Inherits Component 'Component has already implemented IDisposable
I'm trying to write a method that is called from a variety of forms at load. So with a Form1 load event I would call the following:
Dim testpoint As New Point(10, 20) DrawVerticalStringFromBottomUp("Hello", testpoint, Me) The DrawVerticalSTringFromBottomUp Method is as follows:
[Code]....
When I call the code at a form's load event, nothing happens. When I call it from a button click after the form has loaded it works! I know this should be called from the paint method, but that doesn't suit my purposes.
I have a base class called PageBase and then a derived class TestPage that inherits from PageBase. In PageBase I have overridden the OnInit() and when it is called and I inspect the value of 'Me', it is of the type of the derived class and not the base class. My question is how does inheritance really work? For instance, when instantiating TestPage does an instance of PageBase get created too?