更新：2007 年 11 月
获取或设置一个值，该值指示是否将 Items 集合中的菜单项添加到子菜单中。
命名空间： Microsoft.Windows.Design.Interaction
程序集： Microsoft.Windows.Design.Extensibility（在 Microsoft.Windows.Design.Extensibility.dll 中）
语法
声明
Public Property HasDropDown As Boolean
用法
Dim instance As MenuGroup
Dim value As Boolean
value = instance.HasDropDown
instance.HasDropDown = value
public bool HasDropDown { get; set; }
public:
property bool HasDropDown {
bool get ();
void set (bool value);
}
public function get HasDropDown () : boolean
public function set HasDropDown (value : boolean)
属性值
如果要将项集合中的菜单项添加到子菜单中，则为 true；如果要将集合中的项直接添加到当前菜单中，在每端用分隔符来呈现，则为 false。
备注
如果 HasDropDown 等于 true，则将项集合中的菜单项添加到子菜单中。DisplayName 属性设置为 MenuGroup 的菜单项将添加到当前菜单中，菜单项将添加到子菜单中。如果 HasDropDown 等于 false，则将集合中的菜单项直接添加到当前菜单中，并在两端用分隔符来呈现。例如，请考虑一个名为“布局”、具有“左对齐”和“右对齐”菜单项的菜单组。如果 HasDropDown 等于 true，则将向当前菜单中添加一个“布局”菜单，该菜单具有子菜单项“左对齐”和“右对齐”。如果 HasDropDown 等于 false，则将向当前菜单中添加“左对齐”和“右对齐”，在“左对齐”之前和“右对齐”之后各有一个分隔符。
示例
下面的代码示例演示如何设置两个 MenuAction 项并将其分配给 MenuGroup。通过将 HasDropDown 属性设置为 true 可启用飞出行为。有关更多信息，请参见演练：创建 MenuAction。
' The provider's constructor sets up the MenuAction objects
' and the the MenuGroup which holds them.
Public Sub New()
' Set up the MenuAction which sets the control's
' background to Blue.
setBackgroundToBlueMenuAction = New MenuAction("Blue")
setBackgroundToBlueMenuAction.Checkable = True
AddHandler setBackgroundToBlueMenuAction.Execute, AddressOf SetBackgroundToBlue_Execute
' Set up the MenuAction which sets the control's
' background to its default value.
clearBackgroundMenuAction = New MenuAction("Cleared")
clearBackgroundMenuAction.Checkable = True
AddHandler clearBackgroundMenuAction.Execute, AddressOf ClearBackground_Execute
' Set up the MenuGroup which holds the MenuAction items.
Dim backgroundFlyoutGroup As New MenuGroup("SetBackgroundsGroup", "Set Background")
' If HasDropDown is false, the group appears inline,
' instead of as a flyout. Set to true.
backgroundFlyoutGroup.HasDropDown = True
backgroundFlyoutGroup.Items.Add(setBackgroundToBlueMenuAction)
backgroundFlyoutGroup.Items.Add(clearBackgroundMenuAction)
Me.Items.Add(backgroundFlyoutGroup)
' The UpdateItemStatus event is raised immediately before
' this provider shows its tabs, which provides the opportunity
' to set states.
AddHandler UpdateItemStatus, AddressOf CustomContextMenuProvider_UpdateItemStatus
End Sub
// The provider's constructor sets up the MenuAction objects
// and the the MenuGroup which holds them.
public CustomContextMenuProvider()
{
// Set up the MenuAction which sets the control's
// background to Blue.
setBackgroundToBlueMenuAction = new MenuAction("Blue");
setBackgroundToBlueMenuAction.Checkable = true;
setBackgroundToBlueMenuAction.Execute +=
new EventHandler<MenuActionEventArgs>(SetBackgroundToBlue_Execute);
// Set up the MenuAction which sets the control's
// background to its default value.
clearBackgroundMenuAction = new MenuAction("Cleared");
clearBackgroundMenuAction.Checkable = true;
clearBackgroundMenuAction.Execute +=
new EventHandler<MenuActionEventArgs>(ClearBackground_Execute);
// Set up the MenuGroup which holds the MenuAction items.
MenuGroup backgroundFlyoutGroup =
new MenuGroup("SetBackgroundsGroup", "Set Background");
// If HasDropDown is false, the group appears inline,
// instead of as a flyout. Set to true.
backgroundFlyoutGroup.HasDropDown = true;
backgroundFlyoutGroup.Items.Add(setBackgroundToBlueMenuAction);
backgroundFlyoutGroup.Items.Add(clearBackgroundMenuAction);
this.Items.Add(backgroundFlyoutGroup);
// The UpdateItemStatus event is raised immediately before
// this provider shows its tabs, which provides the opportunity
// to set states.
UpdateItemStatus +=
new EventHandler<MenuActionEventArgs>(
CustomContextMenuProvider_UpdateItemStatus);
}
权限
- 对直接调用方的完全信任。此成员不能由部分信任的代码使用。有关更多信息，请参见通过部分受信任的代码使用库。
另请参见
参考
Microsoft.Windows.Design.Interaction 命名空间
PrimarySelectionContextMenuProvider