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???Dispose dynamic menu items
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Microsoft Dot NET Framework Forms
???Dispose dynamic menu items
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???Dispose dynamic menu items |
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#1 |
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Guest
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Hi People
I have a WinForm program. The UI contains a ToolStripDropdownButton, which is associate a list of menu items of ToolStripMenuItem, created dynamically. Upon different scenarios of user operations, the DropdowButton need to clean up all its menuitems, and create new ones. Here the codes: //////////////////// Void CreateForEmail() { .... button.DropDownItems.Clear(); .... button.DropDownItems.Add("To:", null, HandleOutlookToClick); button.DropDownItems.Add("CC:", null, HandleOutlookCCClick); } Void CreateForPhone() { .... button.DropDownItems.Clear(); .... button.DropDownItems.Add("Phone", null, HandlePhoneClick); } Void CreateForNone() { button.DropDownItems.Clear(); } //////////////////////// So far so good, just work as I expect. Later on, I found out that " button.DropDownItems.Clear();" does not dispose the menu items at all, when I decided to add shortcutkeys to menu items. The above codes were changed in order to have shortCutKeys: //////////////////// Void CreateForEmail() { .... button.DropDownItems.Clear(); .... button.DropDownItems.Add("To:", null, HandleOutlookToClick) ..ShortcutKeys = Keys.F9;; button.DropDownItems.Add("CC:", null, HandleOutlookCCClick); } Void CreateForPhone() { .... button.DropDownItems.Clear(); .... button.DropDownItems.Add("Phone", null, HandlePhoneClick) .ShortcutKeys = Keys.F9;; } Void CreateForNone() { button.DropDownItems.Clear(); } //////////////////////// After CreateForNone is called, and I press F9, either HandleOutlookToClick or HandlePhoneClick will be called, depending which one was last called. Obviously, those menu items are still in the program accepting keyboard shortcut, though they are not invisible. So I replace "button.DropDownItems.Clear();" with the following //////////////// private void ClearButtonDropdown() { for (int i = Button.DropDownItems.Count - 1; i >= 0; i--) { ToolStripMenuItem m = Button.DropDownItems[i] as ToolStripMenuItem; Button.DropDownItems.Remove(m); m.Dispose(); } Button.DropDownItems.Clear(); // even GC.Collect() will not have effect. } /////////////// However, strange things remain the same. Obviously someone is still holding references to those menu items, stopping GC from disposing those items. Can you point out how to dispose these menu items? Cheers Andy |
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#2 |
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Guest
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On 10/01/2007 in message
<1168400437.072054.298070@k58g2000hse.googlegroups.com> Andy Lotus wrote: >However, strange things remain the same. >Obviously someone is still holding references to those menu items, >stopping GC from disposing those items. > >Can you point out how to dispose these menu items? This is a function to remove items from a List - it is in C# but the principle is the same: public void Remove(ContainerListViewItem item) { item.MouseDown -= new MouseEventHandler(OnMouseDown); List.Remove(item); } As you can see it removes the event handler so allowing the object to be disposed. I haven't done BASIC for years so I don't know if you have the '-=' operator though? -- Jeff Gaines |
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