VS 2008 Inherit ListView - Dispose Of Two Objects When The Form's Disposing Of It's Objects
Feb 7, 2010
I have a user control that inherits the FW ListView and I need to dispose of two objects when the form's disposing of it's objects. Here's what I've concluded already, am I on the right track?
In My application, I have an MDI form. From MDI form I open all forms as child forms. I have implemented IDisposable for all large objects like file stream DB connection etc. In the Form_Disposed event I dispose all unmanaged objects. After the child form is closed, all unmanaged objects are disposed but managed objects (controls and form) are not disposed and still in memory. I find it from .Net Memory Profiler ([URL]).
So I have write code to remove all event handlers of all controls and form. Now, When form closed, dispose is called and all event handlers and controls are disposed, but controls and form are still in memory.
I'm trying to fix all my project warning according to Microsoft code analysis (CA:XXXXX) One of the warning is "CA2000: Dispose objects before losing scope" My Code is:
I misidentified the problem. It is actually like this:[code...]
Code analysis complains about this because ms can be disposed twice. That will only be true if zStrm, which takes the memory stream as an argument to its constructor, disposes of the memory stream when it cleans up. That seems like a totally nutty thing for the disposer to be doing. Does it really do that? Would a class that takes another class as an argument, be so uncivil as to dispose of that argument?
I suppose it would, since the alternative would be that the memory stream might not be disposed at all if it was created in the constructor like this:[code...]
I guess the only real question is whether or not I have to worry about this?
I have a button which opens FormTest. When FormTest opens, it creates an instance of ClassTest and that class instance takes the form instance that called it (FormTest) so that it can perform operations on FormTest from the ClassTest class instance. So i have a form which owns an instance of a class which has a reference to the form.
I can't believe I'm still confused about this but, any way, lets finally nail it:I have a class that overrides OnPaint to do some drawing. To speed things up, I create the pens, brushes etc before hand, in the constructor, so that OnPaint does not need to keep creating and disposing them.
Now, I make sure that I always dispose of such objects, but I have the feeling I don't need to because, despite the fact they implement IDisposable, they're managed objects. I've been vigilant in always using 'using' so that I don't need to go through all my code checking. I just wanted to be clear that I wasn't being a pointless user.As an aside, I did have a strange situation, recently, where I had to replace a using block and manually call dispose! I'll dig that out and create a new question.
I am writing a game editor, and have a lot of different "tool" objects. They all inherit from BTool and have the same constructor. I would like to dynamically populate a toolbox at runtime with buttons that correspond to these tools, and when clicked have them create an instance of that tool and set it as the current tool. Is this possible, and if so will it be better/easier than creating those buttons by hand?
I am implementing IDisposable for a class and while disposing there is a internal list of disposable objects. Should I be disposing those object by looping through them.
public Class MyDisposable Implements IDisposable private _disposbaleObjects as new List(of OtherDisposables)
say you have a sub containing an io.streamwriter. That streamwriter is declared and used only inside that sub (and not as static). Should you still call dispose on that streamwriter or is it disposed automatically as it is no longer in use after that sub, until you call that sub again?
I am getting this error, Not sure why it is happening "Error The SqlParameterCollection only accepts non-null SqlParameter type objects, not Int32 objects."I have tried with all sorts of possibilties, now try to enter default data as dummy data,
Using connection As New SqlConnection connection.ConnectionString = ConfigurationManager.ConnectionStrings("DentalDeviceConnectionString").ConnectionString connection.Open()[code].....
I want to let the user input objects to a richtextbox 1 object on each line, and somehow use Random.Next to select pseudorandomly a few objects, the number 'few' inputted in a textbox.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Using conn As New SqlConnection("Database=Clinic_Management_System;Data Source=.SQLExpress;Integrated Security=True;AttachDBFilename=|DataDirectory|Clinic Management System.mdf") Dim cmdRecord As SqlCommand
long story short, I have created a ListView type control, using UserControls for the parent control and the ListViewItems. Most the of the control is written and works fine, right up to the point where I tried to replicate the 'Control.SelectedItems(0).Index' property and the 'SelectedIndexChanged' event.
Each child object knows its index value, and could pass this value via the SelectedIndexChanged event (assuming this is how it works in a normal ListView control -- user clicks on an item, and that item fires an event updating the selected index value in the parent object).
How does the child object raise an event in the parent object? I have a feeling this could be done with Delegates, but I'm still learning about their usage.
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]
I'm trying to set up a system to resize multiple objects on a form (40+) when the form resizes. I've got it working but it's rather slow, when I resize the form it stutters a lot from looping through the objects to resize them. Is there a better way to do this that would not cause the stuttering effect?
I want to compare two objects to check if all the properites of both the object have same value or not. for this i need to use the reflection to enumarate through all the properties of an object and check the value of the property. To try the code just i have written a Employee Class having Two Properties EmployeeNo and EmployeeName. I am creating an object of the Employee class and need to write a function that can list the values of all the properties in the class.
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 am trying a example codes of animated graphics. I rewrote all the code and I found an error which doesn't happen on the example code(I run the example project)
error: 'Protected Overrides Sub Dispose(disposing As Boolean)' has multiple definitions with identical signatures.
when I double clicked the error, I got this in Form1.Designer.vb:
'Form overrides dispose to clean up the component list. <System.Diagnostics.DebuggerNonUserCode()> _ Protected Overrides Sub Dispose(ByVal disposing As Boolean)
I have a nested class, let's call it class1 and it has class2 inside it; VB.Net eg:[code]
1) How can I define X number of Class2 objects[let's call it: Node(x) array]** with NEW() subroutine called?' this raises error: dim cls2(n) as new class2 end sub.
2) How can I return actual number of Node() array? [code]Outside my class in main project I define cls1 object:[code]Now an array of class2 is created inside cls1.
3) Now,How can I access All of them[node(x) array which is created inside cls1] with all properties and methods available?
I remember I wrote a ProcessManager class with this functionality in .net 2003, nearly 4 years age, I don't have the code now.
I need two seperate lists, which every item is Integer, String, Bitmap - and one which every item is Integer, String String. However I don't know how to do this, or even where to look - I've googled for custom objects and custom object lists. What I'm trying to do is this.Custom Object1 is Integer, String, Bitmap Custom Object2 is Integer, String, String
In one thread I'll be adding items to List1(Of Object1), and processing them, and adding the results to List2(Of Object2), however I need to be able from other threads to look at the list and say only give me the items where Integer = (my thread ID), is this possible? Any help, or even links to information that would be relevant to this request would be helpful?
[Code] I want that once I put something in the BigCollection it stays there, I don't want it to be changeable from outside. I want to be able to clear the SmallCollection but it should not be cleared in the BigCollection. Any Ideas?
I know that there is a method for doing this but I can't find what that would be. In my program I am looking to allow the user to create new elements(with code behind them) by entering a certain keystroke say ctrl+v(doesn't matter) and adds a textbox