StateManagedCollection.GetKnownTypes 方法

定義

命名空間:

System.Web.UI

組件:

System.Web.dll

在衍生類別中覆寫時，取得 StateManagedCollection 集合可以包含之 IStateManager 類型的陣列。

protected:
 virtual cli::array <Type ^> ^ GetKnownTypes();

protected virtual Type[] GetKnownTypes ();

abstract member GetKnownTypes : unit -> Type[]
override this.GetKnownTypes : unit -> Type[]

Protected Overridable Function GetKnownTypes () As Type()

傳回

Type[]

已排序 Type 物件的陣列，識別集合可以包含之 IStateManager 物件的類型。 預設實作會傳回 null。

範例

下列程式碼範例示範強型別 StateManagedCollection 類別如何實作 GetKnownTypes 方法。 的實作 GetKnownTypes 會 CycleCollection 傳 Type 回已知型別的陣列，包括 Bicycle 和 Tricycle 型別。 此程式碼範例是提供給 類別之較大範例的 StateManagedCollection 一部分。

//////////////////////////////////////////////////////////////
//
// The strongly typed CycleCollection class is a collection
// that contains Cycle class instances, which implement the
// IStateManager interface.
//
//////////////////////////////////////////////////////////////
[AspNetHostingPermission(SecurityAction.Demand, 
    Level=AspNetHostingPermissionLevel.Minimal)]
public sealed class CycleCollection : StateManagedCollection {
    
    private static readonly Type[] _typesOfCycles 
        = new Type[] { typeof(Bicycle), typeof(Tricycle) };

    protected override object CreateKnownType(int index) {
        switch(index) {
            case 0:
                return new Bicycle();
            case 1:
                return new Tricycle();                    
            default:
                throw new ArgumentOutOfRangeException("Unknown Type");
        }            
    }

    protected override Type[] GetKnownTypes() {
        return _typesOfCycles;
    }

    protected override void SetDirtyObject(object o) {
        ((Cycle)o).SetDirty();
    }
}

'////////////////////////////////////////////////////////////
'
' The strongly typed CycleCollection class is a collection
' that contains Cycle class instances, which implement the
' IStateManager interface.
'
'////////////////////////////////////////////////////////////
<AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
               Public NotInheritable Class CycleCollection
    Inherits StateManagedCollection

    Private Shared _typesOfCycles() As Type = _
        {GetType(Bicycle), GetType(Tricycle)}

    Protected Overrides Function CreateKnownType(ByVal index As Integer) As Object
        Select Case index
            Case 0
                Return New Bicycle()
            Case 1
                Return New Tricycle()
            Case Else
                Throw New ArgumentOutOfRangeException("Unknown Type")
        End Select

    End Function


    Protected Overrides Function GetKnownTypes() As Type()
        Return _typesOfCycles

    End Function


    Protected Overrides Sub SetDirtyObject(ByVal o As Object)
        CType(o, Cycle).SetDirty()

    End Sub
End Class

備註

方法 GetKnownTypes 在方法的 IStateManager.SaveViewState 實作中，由 集合在內部 StateManagedCollection 呼叫。 衍生集合會覆寫 方法， GetKnownTypes 以傳回物件陣列 Type ，這些物件代表集合可以包含的類型。

另請參閱

• CreateKnownType(Int32)