StateManagedCollection 클래스

정의

public ref class StateManagedCollection abstract : System::Collections::IList, System::Web::UI::IStateManager

public abstract class StateManagedCollection : System.Collections.IList, System.Web.UI.IStateManager

type StateManagedCollection = class
    interface IList
    interface ICollection
    interface IEnumerable
    interface IStateManager

Public MustInherit Class StateManagedCollection
Implements IList, IStateManager

상속

Object

StateManagedCollection

파생

System.Web.UI.WebControls.DataControlFieldCollection

System.Web.UI.WebControls.DataPagerFieldCollection

System.Web.UI.WebControls.Expressions.DataSourceExpressionCollection

System.Web.UI.WebControls.HotSpotCollection

System.Web.UI.WebControls.MenuItemBindingCollection

자세히…

구현

ICollection IEnumerable IList IStateManager

예제

다음 코드 예제에서는 강력한 형식의 컬렉션 클래스 StateManagedCollection 를 파생하여 개체를 포함하는 IStateManager 방법을 보여 줍니다. 이 예제에서는 CycleCollection 추상 Cycle 클래스의 인스턴스를 포함하도록 파생됩니다. 이 인스턴스는 개체일 BicycleTricycle 수 있습니다. 클래스는 Cycle 뷰 상태에 속성의 값을 저장하기 때문에 인터페이스를 IStateManager 구현 CycleColor 합니다.

namespace Samples.AspNet.CS.Controls {

    using System;
    using System.Security.Permissions;
    using System.Collections;
    using System.ComponentModel;
    using System.Drawing;           
    using System.Web;
    using System.Web.UI;            
    //////////////////////////////////////////////////////////////
    //
    // 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 abstract Cycle class represents bicycles and tricycles.
    //
    //////////////////////////////////////////////////////////////
    public abstract class Cycle : IStateManager {

        protected internal Cycle(int numWheels) : this(numWheels, "Red"){ }
        
        protected internal Cycle(int numWheels, String color) {    
            numberOfWheels = numWheels;
            CycleColor = color;
        }
        
        private int numberOfWheels = 0;
        public int NumberOfWheels {
            get { return numberOfWheels; }
        }
        
        public string CycleColor {
            get { 
                object o = ViewState["Color"];
                return (null == o) ? String.Empty : o.ToString() ;
            }
            set {
                ViewState["Color"] = value;            
            }        
        }

        internal void SetDirty() {
            ViewState.SetDirty(true);
        }
        
        // Because Cycle does not derive from Control, it does not 
        // have access to an inherited view state StateBag object.
        private StateBag viewState;
        private StateBag ViewState {
            get {
                if (viewState == null) {
                    viewState = new StateBag(false);
                    if (isTrackingViewState) {
                        ((IStateManager)viewState).TrackViewState();
                    }
                }
                return viewState;
            }
        }

        // The IStateManager implementation.
        private bool isTrackingViewState;
        bool IStateManager.IsTrackingViewState {
            get {
                return isTrackingViewState;
            }
        }

        void IStateManager.LoadViewState(object savedState) {
            object[] cycleState = (object[]) savedState;
            
            // In SaveViewState, an array of one element is created.
            // Therefore, if the array passed to LoadViewState has 
            // more than one element, it is invalid.
            if (cycleState.Length != 1) {
                throw new ArgumentException("Invalid Cycle View State");
            }
            
            // Call LoadViewState on the StateBag object.
            ((IStateManager)ViewState).LoadViewState(cycleState[0]);
        }

        // Save the view state by calling the StateBag's SaveViewState
        // method.
        object IStateManager.SaveViewState() {
            object[] cycleState = new object[1];

            if (viewState != null) {
                cycleState[0] = ((IStateManager)viewState).SaveViewState();
            }
            return cycleState;
        }

        // Begin tracking view state. Check the private variable, because 
        // if the view state has not been accessed or set, then it is not  
        // being used and there is no reason to store any view state.
        void IStateManager.TrackViewState() {
            isTrackingViewState = true;
            if (viewState != null) {
                ((IStateManager)viewState).TrackViewState();
            }
        }        
    }

    public sealed class Bicycle : Cycle {
    
        // Create a red Cycle with two wheels.
        public Bicycle() : base(2) {}    
    }
    
    public sealed class Tricycle : Cycle {
    
        // Create a red Cycle with three wheels.
        public Tricycle() : base(3) {}
    }
}

Imports System.Security.Permissions
Imports System.Collections
Imports System.ComponentModel
Imports System.Drawing
Imports System.Web
Imports System.Web.UI
 
Namespace Samples.AspNet.VB.Controls
    '////////////////////////////////////////////////////////////
    '
    ' 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
    '////////////////////////////////////////////////////////////
    '
    ' The abstract Cycle class represents bicycles and tricycles.
    '
    '////////////////////////////////////////////////////////////

    MustInherit Public Class Cycle
        Implements IStateManager


        Friend Protected Sub New(ByVal numWheels As Integer) 
            MyClass.New(numWheels, "Red")

        End Sub

        Friend Protected Sub New(ByVal numWheels As Integer, ByVal color As String) 
            numOfWheels = numWheels
            CycleColor = color

        End Sub

        Private numOfWheels As Integer = 0    
        Public ReadOnly Property NumberOfWheels() As Integer 
            Get
                Return numOfWheels
            End Get
        End Property 

        Public Property CycleColor() As String 
            Get
                Dim o As Object = ViewState("Color")
                If o Is Nothing Then 
                    Return String.Empty
                Else  
                    Return o.ToString()
                End If            
            End Get
            Set
                ViewState("Color") = value
            End Set
        End Property


        Friend Sub SetDirty() 
            ViewState.SetDirty(True)

        End Sub

        ' Because Cycle does not derive from Control, it does not 
        ' have access to an inherited view state StateBag object.
        Private cycleViewState As StateBag

        Private ReadOnly Property ViewState() As StateBag 
            Get
                If cycleViewState Is Nothing Then
                    cycleViewState = New StateBag(False)
                    If trackingViewState Then
                        CType(cycleViewState, IStateManager).TrackViewState()
                    End If
                End If
                Return cycleViewState
            End Get
        End Property

        ' The IStateManager implementation.
        Private trackingViewState As Boolean

        ReadOnly Property IsTrackingViewState() As Boolean _
            Implements IStateManager.IsTrackingViewState
            Get
                Return trackingViewState
            End Get
        End Property


        Sub LoadViewState(ByVal savedState As Object) _
            Implements IStateManager.LoadViewState
            Dim cycleState As Object() = CType(savedState, Object())

            ' In SaveViewState, an array of one element is created.
            ' Therefore, if the array passed to LoadViewState has 
            ' more than one element, it is invalid.
            If cycleState.Length <> 1 Then
                Throw New ArgumentException("Invalid Cycle View State")
            End If

            ' Call LoadViewState on the StateBag object.
            CType(ViewState, IStateManager).LoadViewState(cycleState(0))

        End Sub


        ' Save the view state by calling the StateBag's SaveViewState
        ' method.
        Function SaveViewState() As Object Implements IStateManager.SaveViewState
            Dim cycleState(0) As Object

            If Not (cycleViewState Is Nothing) Then
                cycleState(0) = _
                CType(cycleViewState, IStateManager).SaveViewState()
            End If
            Return cycleState

        End Function


        ' Begin tracking view state. Check the private variable, because 
        ' if the view state has not been accessed or set, then it is not being 
        ' used and there is no reason to store any view state.
        Sub TrackViewState() Implements IStateManager.TrackViewState
            trackingViewState = True
            If Not (cycleViewState Is Nothing) Then
                CType(cycleViewState, IStateManager).TrackViewState()
            End If

        End Sub
    End Class


    Public NotInheritable Class Bicycle
        Inherits Cycle


        ' Create a red Cycle with two wheels.
        Public Sub New()
            MyBase.New(2)

        End Sub
    End Class

    Public NotInheritable Class Tricycle
        Inherits Cycle


        ' Create a red Cycle with three wheels.
        Public Sub New()
            MyBase.New(3)

        End Sub
    End Class
End Namespace

설명

클래스는 StateManagedCollection 요소를 저장하는 IStateManager 강력한 형식의 모든 컬렉션(예DataControlFieldCollection: , ParameterCollection및 StyleCollectionTreeNodeBindingCollection기타)의 기본 클래스입니다. 컬렉션은 StateManagedCollection 포함된 요소의 상태뿐만 아니라 자체 상태를 관리합니다. 따라서 컬렉션의 상태 및 컬렉션에 현재 포함 된 모든 요소의 상태를 저장 하는 IStateManager.SaveViewState 호출 합니다.

클래스에서 StateManagedCollection 파생할 때 고려해야 할 가장 중요한 메서드는 CreateKnownType, GetKnownTypes, OnValidateSetDirty및 SetDirtyObject. 및 CreateKnownType 메서드는 GetKnownTypes 포함된 요소의 형식에 대한 인덱스 뷰 상태를 저장하는 데 사용됩니다. 정규화된 형식 이름이 아닌 인덱스를 저장하면 성능이 향상됩니다. 이 OnValidate 메서드는 컬렉션의 요소가 조작될 때마다 호출되며 비즈니스 규칙에 따라 요소의 유효성을 검사합니다. 현재 메서드 OnValidate 를 구현하면 개체가 컬렉션에 저장되지 않습니다. 그러나 이 메서드를 재정의 null 하여 파생 형식에서 사용자 고유의 유효성 검사 동작을 정의할 수 있습니다. 이 메서드는 SetDirty 마지막으로 로드된 이후의 상태 변경 내용을 직렬화하는 대신 전체 컬렉션을 직렬화하여 상태를 표시하도록 합니다. 이 SetDirtyObject 메서드는 요소 수준에서 이 동일한 동작을 수행하기 위해 구현할 수 있는 추상 메서드입니다.

추가 정보

• IStateManager
• StateBag