MenuGroup.HasDropDown 屬性

發行項
08/12/2011

取得或設定值，這個值表示是否要將 Items 集合中的功能表項目加入至子功能表。

命名空間： Microsoft.Windows.Design.Interaction
組件： Microsoft.Windows.Design.Interaction (在 Microsoft.Windows.Design.Interaction.dll 中)

語法

'宣告
Public Property HasDropDown As Boolean
    Get
    Set

public bool HasDropDown { get; set; }

public:
property bool HasDropDown {
    bool get ();
    void set (bool value);
}

member HasDropDown : bool with get, set

function get HasDropDown () : boolean
function set HasDropDown (value : boolean)

屬性值

型別：System.Boolean
如果會將項目集合中的功能表項目加入至子功能表，則為 true；如果直接將集合中的項目加入至目前的功能表，並且在每個項目兩端以分隔符號來呈現，則為 false。

備註

如果 HasDropDown 等於 true，則項目集合中的功能表項目都會加入至子功能表。其 DisplayName 屬性設定為 MenuGroup 的功能表項目會加入至目前的功能表，而這個功能表的功能表項目則會加入至子功能表。如果 HasDropDown 等於 false，則集合中的功能表項目都會直接加入至目前的功能表，並且在每個項目兩端以分隔符號來呈現。例如，假設有名為 [Layout] 的功能表群組，其功能表項目為 [Align Left] 和 [Align Right]。如果 HasDropDown 等於 true，則會將 [Layout] 功能表加入至目前的功能表，而其子功能表項目為 [Align Left] 和 [Align Right]。如果 HasDropDown 等於 false，則會將 [Align Left] 和 [Align Right] 加入至目前的功能表，並且 [Align Left] 之前和 [Align Right] 之後都各有一個分隔符號。

範例

下列程式碼範例說明如何設定兩個 MenuAction 項目，並將它們指派給 MenuGroup。 HasDropDown 屬性會設定為 true 以啟用延伸式行為。如需詳細資訊，請參閱逐步解說：建立功能表提供者。

' 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);
}