Dispose Of Each Child Control Before Disposing Of Parent Control?

May 22, 2010

I am using Visual Basic .Net 2005 professional.From what I understand, I should be disposing of any object that is an unmanaged resource. I understand the best way to tell if a resource is unmanaged is if it has a Dispose method. ie: If I type a dot after my object, intellisense shows .Dispose() as one of the options. If it does, it's an unmanaged resource. Is that correct? In that case, pretty much every control is an unmanaged resource: buttons, forms, panels, etc.In the application I am working on I use an MDIparent container form, which contains MDI children forms, which themselves contain Panels, Menus, Groupboxes, etc, which in turn contain Buttons, Textboxes, Labels, Dropdowns, etc.Do I have to dispose of each button, textbox, label and dropdown within a panel before disposing of the panel?

Do I have to dispose of each panel, menu, and groupbox before disposing of the MDI child form?.Or can I just call the Dispose() method of the MDIchild form and the GarbageCollector will take care of all the controls and resources within the form?Watching the "mem usage" in Windows Task Manager seems to be an unreliable way to detect if I have a memory leak. The numbers just keep climbing and falling (mostly climbing) erratically and without any activity performed on the application. Is there some (relatively) easy way to detect leaks?

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Get Reference To Parent Control From Child Control?

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I have a UserControl named DataGridViewFilterAndSorter that I built using a SplitContainer. In each Panel of the SplitContainer contains a FlowLayoutPanel and in each FlowLayoutPanel contains a LinkLabel.

I have a procedure that accepts a reference to one of the FlowLayoutPanels in the UserControl. I want to get a reference to the UserControl (DataGridViewFilterAndSorter) using the FlowLayoutPanel reference. Currently, I have to use this[code]...

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I would like to know if there is some simple code to release a child control from it's parent control, without having to name the parent control. In pseudocode, I'm looking for something like this:

[Code]...

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I looked at the Dispose() method in System.Data.SqlClient.SqlTransaction (using a decompiler):

[Code]....

Why does everyone say in forums that it is Rolling back in the dispose? Where does it rollback?

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Moving Child Control Within Bounds Of Parent

Nov 27, 2009

I need a solution to move a child control with in the bounds of a parent control means I had a panel with 300*300 pixels and I had to move a textbox within the panel how?

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Parent!ControlName.Property

I don't know what the ! is supposed to mean, but I get an error here: Class 'System.Windows.Forms.Control' cannot be indexed because it has no default property.

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I try to access the MainContentBlock control from the aspx, but unable to do so. In the aspx file I have registered both controls:

[Code]...

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[Code]...

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2003 Control On Child Form To Create Event On Parent Form?

Oct 28, 2010

Here is the pertinent part of my code:

Public Class Form1
Inherits System.Windows.Forms.Form
Private Sub MenuItem3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

[code].....

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Resize Parent Control From Child's Resize Event?

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I'm starting work updating an UI for one of my company's applications and I'm running into a sticky issue. The parent control contains several panels, each of which can be turned on or off depending on user input.

The final panel in the user control contains another user control which gets resizes according to a toggle switch. Essentially, it "opens" up more information.

While the child control (ChildControl) is docked to Fill inside the parent control (ParentControl), when I add height to ChildControl I can't get ParentControl's height to get updated as well. Currently I'm handling the ChildControl.Layout event in ParentControl but I can't seem to reach that code. To resize ChildControl, I'm calling Me.Height += 200 in ChildControl.vb.

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VS 2010 Changing Control Parent Property Changes Control Location Position?

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I'm trying to make a program with transparent labels over pictureboxes and when I set the label Parent to the PictureBox the position of the label changes.

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Order Of Creation Or Adding To The Parent Control Determines Whether Or Not A Control's Dock Property Supersedes Another's

Jun 17, 2010

i frequently have troubles with the dock property. it seems that either the order of creation or adding to the parent control determines whether or not a control's dock property supersedes another's. e.g. a control with the dockstyle fill will overlap with another docked control on the same parent. does anyone know what the rules are to determine how docking will behave; particularly in dynamically created GUIs?

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Bind Property Of User Control To One Of The Parent Control's Fields?

Dec 30, 2011

If I need access to the value of a user control's property BEFORE PreRender, would I need to base the custom control off of one of the preexisting data controls (repeater, listview,etc.)?One of my user controls features a gridview control that is configured based on the user control's properties on which it resides. Several of the key properties alter the SQL Statement for the underlying recordsource. I'm now in a situation where the property that sets the WHERE statement for the SQL Statement needs to tied to a value in the user control's parent FormView. Think of the formview as displaying a customer detail record. The user control takes the customer's account number and then displays data from a related table such as Customer Contact Names. Since the gridview is created before the control's prerender event, working within the prerender event doesn't seem efficient.

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Does Dispose(disposing As Boolean) Need Implementing For Every Class In A Chain

May 9, 2012

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

[code]....

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Jun 30, 2010

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Aug 19, 2009

I am still messing around with Cntrl/Copy and Paste from a menustrip. Paste is working fine. The copy is working to a certain extent. It will copy the complete text field from one control to another. how do I determine what is the selected text only. My code below:

Private Sub CopyToolStripMenuItem_Click(ByVal sender As Object, ByVal e As EventArgs) Handles CopyToolStripMenuItem.Click
Dim activeChild As Form = Me.ActiveMdiChild ' Determine the active child form.
Dim activeControl As Control = activeChild.ActiveControl

[code]....

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Nov 30, 2009

i need a solution to drag and drop a child control with in the bounds of a parent control means i had a panel with 300*300 pixels and i had to drag and drop a textbox within the panel how

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Error: 'Protected Overrides Sub Dispose(disposing As Boolean)' Has Multiple Definition

May 12, 2009

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)

[Code]....

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VS 2008 Child Control In Another Child Control?

Oct 24, 2009

In my form I hace a Groupbox1, within Groupbox1 have a Groupbox2, within Groupbox2 have a Textbox1..how to call the Texbox1 from another form? When I use Dim newControl As Control = Form1.Controls(Textbox1.Name) I get nothing value?if I use Form1.Controls(Groupbox1.Name) it can get the Groupbox1

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User-control's Dispose ?

Mar 17, 2009

I have a very strange probem:Step1: I have a form A with a button on it. In the button's click event, run this code:

CODE:

There is a button too. In it's click event, run this code:

CODE:

Step3: On the FormC, there is a user-control, doublechosebox, it's set up in the FormC's class declaration, and destroyed in the FormC's formclosing event:

CODE:

ClassStep4: In the user-control DoubleChoseBox, there is a listbox, and bound it to a dataset.Now repeat the problem:S1. Just click the bnOnFormA, it will create the FormB, then click the bnOnFormB, it will create the FormC, with the doublechosebox. Close the FormC, and close the FormB.S2. Click the bnOnFormA again, it will create the FormB again. Close the FormB. 3. Do S2 AGAIN and AGAIN.4. After many times, it will report an error: said that not reffering to an object's instance, in the Doublechosebox's listbox_SelectedIndexChanged event!

My question is:In the formC's formclosing event, I really do the Me.DoubleChosebox1.Dispose(). So I think user-conrol is disposed already. Why still there is error arised from it?The Doublechosebox is inside the FormC's Class, every time when I click the bnOnFormB, it use showdialog to show the formC, it mean's not to create a new one, but still use the same formC? If so, the doublechosebox is disposed during the formclosing, maybe this the problem?

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Feb 18, 2011

Im working with MDI parent/child objects. when closing the child objects i need the child to check to see if it is the last child object before closing. i couldn't find anything on google, maybe im searching for the wrong thing.

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Jun 13, 2011

I have a control that invoke as : Using frmAssemblies As New MaintainMenuItems.bundleDGV(Me, MaintainMenuItems.bundleDGV.formState.pricingEdits, APSite.xrefID)

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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?

[Code]...

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VS 2005 Disposing A MDI Child Form?

May 27, 2010

Quote:

Dim MyForm As Form
MyForm = New Form1()
With MyForm

[Code].....

i use these code to dispose a MDI Child form, but it automatically close the form.. What should I do?

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.net - Parent/Child Relationships Failing When Getting Data From Parent Class With Multiple Forms Open?

Jun 24, 2009

I have a main form, and some sub forms, and each sub form can have some sub forms. When I have multiple sub forms open, and I try to get data from the parent form, it returns the data from the wrong parent form.For example I have two instances of Mainform.subform running. If I do something like this in a child form of one instance of the subform. It returns data from the other subform.

dim l = Mainform.subform.listofdata

Edit:I am using visual Studio 2008. Winforms, form designed using designer. In my mainform I am doing this

Protected Friend frmMain as Mainform
frmmain = new mainform

In frmMain I am doing this

Protected Friend frmsub as new Subform'
frmsub = new subform

[code]....

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Creating DataRelation With Parent And Child Tables And Generating Xml With Subnodes For Child Table?

May 21, 2012

Dim obj_DataTable As New System.Data.DataTable("Category")
Dim obj_DataSet As New DataSet()
'Declaring the array of DataColum to hold the Primary Key Columns

[code].....

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Bind Child/Parent Instead Of Parent/Child?

Apr 28, 2009

Applications_Type is a lookup table for Applications.What I am trying to do is provide a drop down list of applications and a label that displays the selected application type.[code]...

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