StateManagedCollection Sınıf

Tanım

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

Devralma

Object

StateManagedCollection

Türetilmiş

System.Web.UI.WebControls.DataControlFieldCollection

System.Web.UI.WebControls.DataPagerFieldCollection

System.Web.UI.WebControls.HotSpotCollection

System.Web.UI.WebControls.MenuItemBindingCollection

System.Web.UI.WebControls.MenuItemStyleCollection

System.Web.UI.WebControls.ParameterCollection

System.Web.UI.WebControls.StyleCollection

System.Web.UI.WebControls.SubMenuStyleCollection

System.Web.UI.WebControls.TreeNodeBindingCollection

System.Web.UI.WebControls.TreeNodeStyleCollection

System.Web.UI.WebControls.Expressions.DataSourceExpressionCollection

Uygulamalar

ICollection IEnumerable IList IStateManager

Örnekler

Aşağıdaki kod örneği, nesneleri içerecek şekilde türü kesin belirlenmiş bir koleksiyon sınıfının nasıl türetileceğini göstermektedir StateManagedCollection IStateManager .The following code example demonstrates how to derive a strongly typed collection class from StateManagedCollection to contain IStateManager objects. Bu örnekte,, ya CycleCollection da nesneler olabilen soyut sınıfın örneklerini içerir Cycle Bicycle Tricycle .In this example, the CycleCollection is derived to contain instances of the abstract Cycle class, which can be either Bicycle or Tricycle objects. CycleSınıfı, IStateManager özelliğin değerini Görünüm durumunda depoladığından arabirimini uygular CycleColor .The Cycle class implements the IStateManager interface because it stores the value of the CycleColor property in view state.

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

Açıklamalar

Sınıfı,,,, StateManagedCollection IStateManager DataControlFieldCollection ParameterCollection StyleCollection TreeNodeBindingCollection ve diğerleri dahil olmak üzere öğeleri depolayan, kesin olarak belirlenmiş tüm koleksiyonlar için temel sınıftır.The StateManagedCollection class is the base class for all strongly typed collections that store IStateManager elements, including DataControlFieldCollection, ParameterCollection, StyleCollection, TreeNodeBindingCollection, and others. StateManagedCollectionKoleksiyon kendi durumunu ve içerdiği öğelerin durumunu yönetir.The StateManagedCollection collection manages its own state as well as the state of the elements it contains. Bu nedenle, koleksiyonun IStateManager.SaveViewState durumunu ve koleksiyonda bulunan tüm öğelerin durumunu kaydeden bir çağrı.Therefore, a call to IStateManager.SaveViewState saves the state of the collection and the state of all the elements currently contained by the collection.

Sınıfından türetmede dikkate alınması gereken en önemli Yöntemler StateManagedCollection ,,, CreateKnownType GetKnownTypes OnValidate SetDirty ve SetDirtyObject .The most important methods to consider when deriving from the StateManagedCollection class are CreateKnownType, GetKnownTypes, OnValidate, SetDirty, and SetDirtyObject. CreateKnownTypeVe GetKnownTypes yöntemleri kapsanan bir öğenin türü için Görünüm durumunda bir dizini depolamak için kullanılır.The CreateKnownType and GetKnownTypes methods are used to store an index in view state for the type of a contained element. Tam nitelikli tür adı yerine bir dizinin depolanması performansı geliştirir.Storing an index rather than a fully qualified type name improves performance. OnValidateYöntemi, koleksiyon öğelerinin her değiştirildiğinde çağrılır ve öğeleri iş kurallarına göre doğrular.The OnValidate method is called whenever elements of the collection are manipulated, and validates the elements according to business rules. Şu anda, OnValidate yönteminin uygulanması null nesnelerin koleksiyonda depolanmasını yasaklamaktadır; ancak, türetilmiş bir tür içinde kendi doğrulama davranışınızı tanımlamak için bu yöntemi geçersiz kılabilirsiniz.Currently, the implementation of the OnValidate method prohibits null objects from being stored in the collection; however, you can override this method to define your own validation behavior in a derived type. SetDirtyYöntemi, son yüklendiği zamandan bu yana yalnızca durum üzerinde yapılan değişiklikleri serileştirmek yerine, tüm koleksiyonu durum görüntüleme olarak Serileştirmeye zorlar.The SetDirty method forces the entire collection to be serialized to view state, rather than just serializing changes made to state since the last time it was loaded. SetDirtyObjectYöntemi, aynı davranışı öğe düzeyinde gerçekleştirmek için uygulayabileceğiniz soyut bir yöntemdir.The SetDirtyObject method is an abstract method you can implement to perform this same behavior at the element level.

Oluşturucular

Özellikler

Yöntemler

Belirtik Arabirim Kullanımları

Uzantı Metotları

Şunlara uygulanır

Ayrıca bkz.

• IStateManager
• StateBag