This Menu class represents the submenus of either
a MainMenu, ContextMenu, or
other MenuItem object. You can add it to the
MenuItems property of any of these classes to
create such a submenu.
You can control the appearance of the item with a number of different
properties. You can set the Text for the menu
item, and it can be Enabled, and made
Visible. The BarBreak and
Break properties cause the menu item to start a
new column in the menu, with and without a dividing line,
respectively. Checked determines whether a check
mark appears next to item text, and RadioCheck
determines whether the check mark appears as a radio button instead
of a checkmark. Note that you have to handle the mutual exclusion
yourself. You can set a Shortcut key to associate
with the item, and ShowShortcut determines whether
the key is displayed to the right of the text. You can also find out
which Mnemonic character is acting as an Alt key
shortcut.
To support MDI applications, you can mark an item as the
MdiListItem. The system will automatically create
and maintain a child menu for this object with a list of the MDI
windows owned by the parent Form.
Also for the benefit of MDI and similar applications,
Menu objects allow the merging of their items to
meld together menus from disparate sources. To control this, you can
specify the MergeOrder of a particular item. This
is essentially a numeric priority for the item when merging two
submenus with the same name. A low number will appear higher in the
menu than a higher number. It is best to think of these as numeric
groups where the same numbers will be bundled together in the final
menu.
In addition to the MergeOrder, you can specify the
MergeType. This allows you to specify whether the
system will Add() the item to the existing
collection (this is the default), Remove() the
item when merging (i.e., it will not appear in the final menu),
Replace any existing items at the same position in
the merged menu, or MergeItems: interleave the
items with the existing items, adding and replacing as appropriate.
Note that the settings on both parties in the merge affect the end
results. It is best to play with these options until you get a feel
for how menu merging works in practice.
To determine when items are being manipulated, you can bind to the
Click, Popup (a child menu is
about to appear), and Select (the item has been
highlighted) events. You can programmatically raise these events with
the PerformClick() and PerformSelect() methods.
Note that MenuItem objects also support
OwnerDraw. See
MeasureItemEventArgs and
DrawItemEventArgs for more information on owner
draw facilities.
public class MenuItem : Menu {
// Public Constructors
public MenuItem();
public MenuItem(MenuMerge mergeType, int mergeOrder, Shortcut shortcut, string text, EventHandler onClick,
EventHandler onPopup, EventHandler onSelect, MenuItem[ ] items);
public MenuItem(string text);
public MenuItem(string text, EventHandler onClick);
public MenuItem(string text, EventHandler onClick, Shortcut shortcut);
public MenuItem(string text, MenuItem[ ] items);
// Public Instance Properties
public bool BarBreak{set; get; }
public bool Break{set; get; }
public bool Checked{set; get; }
public bool DefaultItem{set; get; }
public bool Enabled{set; get; }
public int Index{set; get; }
public override bool IsParent{get; }
// overrides Menu
public bool MdiList{set; get; }
public int MergeOrder{set; get; }
public MenuMerge MergeType{set; get; }
public char Mnemonic{get; }
public bool OwnerDraw{set; get; }
public Menu Parent{get; }
public bool RadioCheck{set; get; }
public Shortcut Shortcut{set; get; }
public bool ShowShortcut{set; get; }
public string Text{set; get; }
public bool Visible{set; get; }
// Protected Instance Properties
protected int MenuID{get; }
// Public Instance Methods
public virtual MenuItem CloneMenu();
public virtual MenuItem MergeMenu();
public void MergeMenu(MenuItem itemSrc);
public void PerformClick();
public virtual void PerformSelect();
public override string ToString(); // overrides Menu
// Protected Instance Methods
protected void CloneMenu(MenuItem itemSrc);
protected override void Dispose(bool disposing); // overrides Menu
protected virtual void OnClick(EventArgs e);
protected virtual void OnDrawItem(DrawItemEventArgs e);
protected virtual void OnInitMenuPopup(EventArgs e);
protected virtual void OnMeasureItem(MeasureItemEventArgs e);
protected virtual void OnPopup(EventArgs e);
protected virtual void OnSelect(EventArgs e);
// Events
public event EventHandler Click;
public event DrawItemEventHandler DrawItem;
public event MeasureItemEventHandler MeasureItem;
public event EventHandler Popup;
public event EventHandler Select;
}
System.MarshalByRefObject