ItemPolicy.IsSurrogate 屬性

發行項
08/12/2011

取得值，這個值表示原則是否為代理原則。

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

語法

'宣告
Public Overridable ReadOnly Property IsSurrogate As Boolean
    Get

public virtual bool IsSurrogate { get; }

public:
virtual property bool IsSurrogate {
    bool get ();
}

abstract IsSurrogate : bool
override IsSurrogate : bool

function get IsSurrogate () : boolean

屬性值

型別：System.Boolean
如果原則為代理原則，則為 true，否則為 false。

備註

代理原則可提供另外一組項目集合，這個集合可用來找出功能提供者的位置。代理原則通常是由控制項容器使用，這些容器可提供額外的工作和裝飾項給它們的子系。在這個案例中，容器會提供代理原則，其中 GetSurrogateItems 方法會傳回所提供之項目的父代。

範例

下列程式碼範例示範，如何透過實作 IsSurrogate 屬性和 GetSurrogateItems 方法，以建立自訂代理原則 (Surrogate Policy)。如需完整的程式碼清單，請參閱 HOW TO：建立 Surrogate 原則。

' The DockPanelPolicy class implements a surrogate policy that
' provides container semantics for a selected item. By using 
' this policy, the DemoDockPanel container control offers 
' additional tasks and adorners on its children. 
Class DockPanelPolicy
    Inherits PrimarySelectionPolicy

    Public Overrides ReadOnly Property IsSurrogate() As Boolean 
        Get
            Return True
        End Get
    End Property

    Public Overrides Function GetSurrogateItems( _
        ByVal item As Microsoft.Windows.Design.Model.ModelItem) _
        As System.Collections.Generic.IEnumerable( _
        Of Microsoft.Windows.Design.Model.ModelItem)

        Dim parent As ModelItem = item.Parent

        Dim e As New System.Collections.Generic.List(Of ModelItem)

        If (parent IsNot Nothing) Then

            e.Add(parent)

        End If

        Return e

    End Function

End Class

// The DockPanelPolicy class implements a surrogate policy that
// provides container semantics for a selected item. By using 
// this policy, the DemoDockPanel container control offers 
// additional tasks and adorners on its children. 
class DockPanelPolicy : PrimarySelectionPolicy 
{
    public override bool IsSurrogate 
    {
        get 
        { 
            return true;
        }
    }

    public override IEnumerable<ModelItem> GetSurrogateItems(ModelItem item) 
    {
        ModelItem parent = item.Parent;

        if (parent != null)
        {
            yield return parent;
        }
    }
}