DesignerTransaction Classe

Definizione

Fornisce un metodo per raggruppare una serie di azioni della fase di progettazione per migliorare le prestazioni e consentire l'annullamento della maggior parte dei tipi di modifiche.Provides a way to group a series of design-time actions to improve performance and enable most types of changes to be undone.

public ref class DesignerTransaction abstract : IDisposable
public abstract class DesignerTransaction : IDisposable
type DesignerTransaction = class
    interface IDisposable
Public MustInherit Class DesignerTransaction
Implements IDisposable
Ereditarietà
DesignerTransaction
Implementazioni

Esempi

Nel programma di esempio di codice seguente viene illustrato come DesignerTransaction creare un oggetto da una finestra di progettazione.The following code example program demonstrates how to create a DesignerTransaction from a designer. Per eseguire questo esempio, compilare il codice sorgente in una libreria di classi.To run this sample, compile the source code into a class library. È necessario aggiungere un riferimento all'assembly System. Design.You must add a reference to the System.Design assembly. In un nuovo progetto, aggiungere un riferimento alla DLL compilata e aggiungere il componente nella libreria alla casella degli strumenti.In a new project, add a reference to the compiled DLL and add the component in the library to the Toolbox.

In Visual Studio è disponibile un supporto completo per questa funzionalità.There is extensive support for this feature in Visual Studio.

Vedere anche procedura dettagliata: Popolamento automatico della casella degli strumenti concomponenti personalizzati.Also see Walkthrough: Automatically Populating the Toolbox with Custom Components.

La finestra di progettazione può facoltativamente visualizzare le notifiche sugli eventi di transazione della finestra di progettazione.The designer can optionally display notifications about designer transaction events. Se si aggiunge un'istanza di DTComponent a un form in modalità progettazione, viene visualizzata una finestra di messaggio in cui viene chiesto se si desidera ricevere notifiche degli eventi delle transazioni di progettazione.If you add an instance of the DTComponent to a form while in design mode, a message box appears asking whether you would like to receive designer transaction event notifications. È possibile impostare queste notifiche tramite il menu di scelta rapida visualizzato quando si fa clic con il pulsante destro del DTComponentmouse su un'istanza del.You may toggle these notifications using the shortcut menu that appears when you right-click an instance of the DTComponent. Le transazioni vengono create quando si modificano i valori usando il Finestra Proprietà.Transactions are created when you change values using the Properties window. È inoltre possibile fare in maniera che la finestra di progettazione esegua una transazione facendo clic su Esegui transazione di esempio dal menu di scelta rapida per il componente.You can also have the designer perform a transaction by clicking Perform Example Transaction on the shortcut menu for the component.

#using <system.dll>
#using <system.design.dll>
#using <system.windows.forms.dll>

using namespace System;
using namespace System::ComponentModel;
using namespace System::ComponentModel::Design;
using namespace System::Windows::Forms;
using namespace System::Windows::Forms::Design;

/*
This sample demonstrates how to perform a series of actions in a designer
transaction, how to change values of properties of a component from a
designer, and how to complete transactions without being interrupted
by other activities.

To run this sample, add this code to a class library project and compile.
Create a new Windows Forms project or load a form in the designer. Add a
reference to the class library that was compiled in the first step.
Right-click the Toolbox in design mode and click Customize Toolbox.
Browse to the class library that was compiled in the first step and
select OK until the DTComponent item appears in the Toolbox.  Add an
instance of this component to the form.

When the component is created and added to the component tray for your
design project, the Initialize method of the designer is called.
This method displays a message box informing you that designer transaction
event handlers will be registered unless you click Cancel. When you set
properties in the properties window, each change will be encapsulated in
a designer transaction, allowing the change to be undone later.

When you right-click the component, the shortcut menu for the component
is displayed. The designer constructs this menu according to whether
designer transaction notifications are enabled, and offers the option
of enabling or disabling the notifications, depending on the current
mode. The shortcut menu also presents a Perform Example Transaction
item, which will set the values of the component's StringProperty and
CountProperty properties. You can undo the last designer transaction using
the Undo command provided by the Visual Studio development environment.
*/

private ref class DTDesigner: public ComponentDesigner
{
private:
   bool notification_mode;
   int count;
   void LinkDTNotifications( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      if (  !notification_mode )
      {
         IDesignerHost^ host = dynamic_cast<IDesignerHost^>(GetService( IDesignerHost::typeid ));
         if ( host != nullptr )
         {
            notification_mode = true;
            host->TransactionOpened += gcnew EventHandler( this, &DTDesigner::OnDesignerTransactionOpened );
            host->TransactionClosed += gcnew DesignerTransactionCloseEventHandler( this, &DTDesigner::OnDesignerTransactionClosed );
         }
      }
   }

   void UnlinkDTNotifications( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      if ( notification_mode )
      {
         IDesignerHost^ host = dynamic_cast<IDesignerHost^>(GetService( IDesignerHost::typeid ));
         if ( host != nullptr )
         {
            notification_mode = false;
            host->TransactionOpened -= gcnew EventHandler( this, &DTDesigner::OnDesignerTransactionOpened );
            host->TransactionClosed -= gcnew DesignerTransactionCloseEventHandler( this, &DTDesigner::OnDesignerTransactionClosed );
         }
      }
   }

   void OnDesignerTransactionOpened( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      MessageBox::Show( "A Designer Transaction was started. (TransactionOpened)" );
   }

   void OnDesignerTransactionClosed( Object^ /*sender*/, DesignerTransactionCloseEventArgs^ /*e*/ )
   {
      MessageBox::Show( "A Designer Transaction was completed. (TransactionClosed)" );
   }

   void DoTransaction( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      IDesignerHost^ host = static_cast<IDesignerHost^>(GetService( IDesignerHost::typeid ));
      DesignerTransaction^ t = host->CreateTransaction( "Change Text and Size" );
      
      /* The code within the using statement is considered to be a single transaction.
              When the user selects Undo, the system will undo everything executed in this code block.
              */
      if ( notification_mode )
            MessageBox::Show( "Entering a Designer-Initiated Designer Transaction" );

      // The .NET Framework automatically associates the TypeDescriptor with the correct component
      PropertyDescriptor^ someText = TypeDescriptor::GetProperties( Component )[ "StringProperty" ];
      someText->SetValue( Component, "This text was set by the designer for this component." );
      PropertyDescriptor^ anInteger = TypeDescriptor::GetProperties( Component )[ "CountProperty" ];
      anInteger->SetValue( Component, count );
      count++;

      // Complete the designer transaction.
      t->Commit();
      if ( notification_mode )
            MessageBox::Show( "Designer-Initiated Designer Transaction Completed" );
   }

public:
   property DesignerVerbCollection^ Verbs 
   {
      // The Verbs property is overridden from ComponentDesigner
      virtual DesignerVerbCollection^ get() override
      {
         DesignerVerbCollection^ dvc = gcnew DesignerVerbCollection;
         dvc->Add( gcnew DesignerVerb( "Perform Example Transaction",gcnew EventHandler( this, &DTDesigner::DoTransaction ) ) );
         if ( notification_mode )
                  dvc->Add( gcnew DesignerVerb( "End Designer Transaction Notifications",
                     gcnew EventHandler( this, &DTDesigner::UnlinkDTNotifications ) ) );
         else
                  dvc->Add( gcnew DesignerVerb( "Show Designer Transaction Notifications",
                     gcnew EventHandler( this, &DTDesigner::LinkDTNotifications ) ) );

         return dvc;
      }
   }
   virtual void Initialize( IComponent^ component ) override
   {
      ComponentDesigner::Initialize( component );
      notification_mode = false;
      count = 10;
      IDesignerHost^ host = dynamic_cast<IDesignerHost^>(GetService( IDesignerHost::typeid ));
      if ( host == nullptr )
      {
         MessageBox::Show( "The IDesignerHost service interface could not be obtained." );
         return;
      }

      if ( MessageBox::Show( "Press the Yes button to display notification message boxes for the designer transaction opened and closed notifications.", "Link DesignerTransaction Notifications?", MessageBoxButtons::YesNo, MessageBoxIcon::Question, MessageBoxDefaultButton::Button1, MessageBoxOptions::RightAlign ) == DialogResult::Yes )
      {
         host->TransactionOpened += gcnew EventHandler( this, &DTDesigner::OnDesignerTransactionOpened );
         host->TransactionClosed += gcnew DesignerTransactionCloseEventHandler( this, &DTDesigner::OnDesignerTransactionClosed );
         notification_mode = true;
      }
   }

public:
   ~DTDesigner()
   {
      UnlinkDTNotifications( this, gcnew EventArgs );
   }
};

// Associate the DTDesigner with this component

[DesignerAttribute(DTDesigner::typeid)]
public ref class DTComponent: public System::ComponentModel::Component
{
private:
   String^ m_String;
   int m_Count;
   void InitializeComponent()
   {
      m_String = "Initial Value";
      m_Count = 0;
   }

public:
   property String^ StringProperty 
   {
      String^ get()
      {
         return m_String;
      }

      void set( String^ value )
      {
         m_String = value;
      }
   }

   property int CountProperty 
   {
      int get()
      {
         return m_Count;
      }

      void set( int value )
      {
         m_Count = value;
      }
   }
};
using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Windows.Forms;
using System.Windows.Forms.Design;

/*
    This sample demonstrates how to perform a series of actions in a designer 
    transaction, how to change values of properties of a component from a 
    designer, and how to complete transactions without being interrupted 
    by other activities.

    To run this sample, add this code to a class library project and compile. 
    Create a new Windows Forms project or load a form in the designer. Add a 
    reference to the class library that was compiled in the first step.
    Right-click the Toolbox in design mode and click Customize Toolbox.  
    Browse to the class library that was compiled in the first step and 
    select OK until the DTComponent item appears in the Toolbox.  Add an 
    instance of this component to the form.  
    
    When the component is created and added to the component tray for your
    design project, the Initialize method of the designer is called. 
    This method displays a message box informing you that designer transaction
    event handlers will be registered unless you click Cancel. When you set 
    properties in the properties window, each change will be encapsulated in 
    a designer transaction, allowing the change to be undone later.  
    
    When you right-click the component,	the shortcut menu for the component 
    is displayed. The designer constructs this menu according to whether 
    designer transaction notifications are enabled, and offers the option
    of enabling or disabling the notifications, depending on the current 
    mode. The shortcut menu also presents a Perform Example Transaction 
    item, which will set the values of the component's StringProperty and 
    CountProperty properties. You can undo the last designer transaction using 
    the Undo command provided by the Visual Studio development environment.
*/

namespace DesignerTransactionSample
{
    // Associate the DTDesigner with this component
    [DesignerAttribute(typeof(DTDesigner))]
    public class DTComponent : System.ComponentModel.Component
    {
        private string m_String;
    private int m_Count;
            
    public string StringProperty
    {
        get
            { return m_String; }
        set
        { m_String = value; }
    }
            
    public int CountProperty
    {
        get
        { return m_Count; }
        set
        { m_Count = value; }
    }

    private void InitializeComponent()
    {
        m_String = "Initial Value";
        m_Count = 0;
    }
    }
    
    internal class DTDesigner : ComponentDesigner
    {
    private bool notification_mode = false;
    private int count = 10;
        
    // The Verbs property is overridden from ComponentDesigner
    public override DesignerVerbCollection Verbs
    {
        get
        {				
            DesignerVerbCollection dvc = new DesignerVerbCollection();				
        dvc.Add( new DesignerVerb("Perform Example Transaction", new EventHandler(this.DoTransaction)) );
        if(notification_mode)
            dvc.Add(new DesignerVerb("End Designer Transaction Notifications", new EventHandler(this.UnlinkDTNotifications)));
        else
            dvc.Add(new DesignerVerb("Show Designer Transaction Notifications", new EventHandler(this.LinkDTNotifications)));				return dvc;
        }
    }
        
        public override void Initialize(System.ComponentModel.IComponent component)
        {
            base.Initialize(component);

            IDesignerHost host = (IDesignerHost)GetService(typeof(IDesignerHost));			
            if(host == null)
            {
                MessageBox.Show("The IDesignerHost service interface could not be obtained.");
                return;
            }

            if( MessageBox.Show("Press the Yes button to display notification message boxes for the designer transaction opened and closed notifications.","Link DesignerTransaction Notifications?", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1, MessageBoxOptions.RightAlign) == DialogResult.Yes )
            {							
            host.TransactionOpened += new EventHandler(OnDesignerTransactionOpened);
                host.TransactionClosed += new DesignerTransactionCloseEventHandler(OnDesignerTransactionClosed);
                notification_mode = true;
            }
        }
        
        private void LinkDTNotifications(object sender, EventArgs e)
        {
            if(notification_mode == false)
            {
            IDesignerHost host = (IDesignerHost)GetService(typeof(IDesignerHost));							
                if(host != null)
            {
            notification_mode = true;
                   host.TransactionOpened += new EventHandler(OnDesignerTransactionOpened);
                   host.TransactionClosed += new DesignerTransactionCloseEventHandler(OnDesignerTransactionClosed);
            }
        }
        }

        private void UnlinkDTNotifications(object sender, EventArgs e)
        {
        if(notification_mode)
            {
                IDesignerHost host = (IDesignerHost)GetService(typeof(IDesignerHost));							
            if(host != null)
                {				
            notification_mode = false;
                    host.TransactionOpened -= new EventHandler(OnDesignerTransactionOpened);
                    host.TransactionClosed -= new DesignerTransactionCloseEventHandler(OnDesignerTransactionClosed);
                }
            }
        }

        private void OnDesignerTransactionOpened(object sender, EventArgs e)
        {			
        System.Windows.Forms.MessageBox.Show("A Designer Transaction was started. (TransactionOpened)");
        }

        private void OnDesignerTransactionClosed(object sender, DesignerTransactionCloseEventArgs e)
        {			
        System.Windows.Forms.MessageBox.Show("A Designer Transaction was completed. (TransactionClosed)");
        }   

        private void DoTransaction(object sender, EventArgs e) 
        {			
            IDesignerHost host = (IDesignerHost)GetService(typeof(IDesignerHost));			
            DesignerTransaction t = host.CreateTransaction("Change Text and Size");

            /* The code within the using statement is considered to be a single transaction.
           When the user selects Undo, the system will undo everything executed in this code block. */
            using (t)
            {
            if(notification_mode)
                System.Windows.Forms.MessageBox.Show("Entering a Designer-Initiated Designer Transaction");
                
                // The .NET Framework automatically associates the TypeDescriptor with the correct component
            PropertyDescriptor someText = TypeDescriptor.GetProperties(Component)["StringProperty"];
                someText.SetValue(Component, "This text was set by the designer for this component.");

                PropertyDescriptor anInteger = TypeDescriptor.GetProperties(Component)["CountProperty"];
            anInteger.SetValue(Component, count);
            count++;

                // Complete the designer transaction.
            t.Commit();
                
            if(notification_mode)
                System.Windows.Forms.MessageBox.Show("Designer-Initiated Designer Transaction Completed");
            }
        }
        
    protected override void Dispose(bool disposing)
    {
        UnlinkDTNotifications(this, new EventArgs());
        base.Dispose(disposing);
    }
    }
}
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Windows.Forms
Imports System.Windows.Forms.Design

'   This sample demonstrates how to perform a series of actions in a designer 
'   transaction, how to change values of properties of a component from a 
'   designer, and how to complete transactions without being interrupted 
'   by other activities.

'   To run this sample, add this code to a class library project and compile. 
'   Create a new Windows Forms project or load a form in the designer. Add a 
'   reference to the class library that was compiled in the first step.
'   Right-click the Toolbox in design mode and click Customize Toolbox.  
'   Browse to the class library that was compiled in the first step and 
'   select OK until the DTComponent item appears in the Toolbox.  Add an 
'   instance of this component to the form.  

'   When the component is created and added to the component tray for your
'   design project, the Initialize method of the designer is called. 
'   This method displays a message box informing you that designer transaction
'   event handlers are being registered unless you click Cancel. When you set 
'   properties in the properties window, each change will be encapsulated in 
'   a designer transaction, allowing the change to be undone later.  

'   When you right-click the component, the shortcut menu for the component 
'   is displayed. The designer constructs this menu according to whether 
'   designer transaction notifications are enabled, and offers the option
'   of enabling or disabling the notifications, depending on the current 
'   mode. The shortcut menu also presents a Perform Example Transaction 
'   item which will set the values of the component's StringProperty and 
'   CountProperty properties. You can undo the last designer transaction using 
'   the Undo command provided by the Visual Studio development environment.	

Namespace DesignerTransactionSample

    ' Associate the DTDesigner with this component
    <DesignerAttribute(GetType(DTDesigner))> _
    Public Class DTComponent
        Inherits System.ComponentModel.Component
        Private m_String As String
        Private m_Count As Integer

        Public Property StringProperty() As String
            Get
                Return m_String
            End Get
            Set(ByVal Value As String)
                m_String = Value
            End Set
        End Property

        Public Property CountProperty() As Integer
            Get
                Return m_Count
            End Get
            Set(ByVal Value As Integer)
                m_Count = Value
            End Set
        End Property

        Private Sub InitializeComponent()
            m_String = "Initial Value"
            m_Count = 0
        End Sub

    End Class

    Friend Class DTDesigner
        Inherits ComponentDesigner

        Private notification_mode As Boolean = False
        Private count As Integer = 10

        ' The Verbs property is overridden from ComponentDesigner
        Public Overrides ReadOnly Property Verbs() As DesignerVerbCollection
            Get
                Dim dvc As New DesignerVerbCollection()
                dvc.Add(New DesignerVerb("Perform Example Transaction", AddressOf Me.DoTransaction))
                If notification_mode Then
                    dvc.Add(New DesignerVerb("End Designer Transaction Notifications", AddressOf Me.UnlinkDTNotifications))
                Else
                    dvc.Add(New DesignerVerb("Show Designer Transaction Notifications", AddressOf Me.LinkDTNotifications))
                End If
                Return dvc
            End Get
        End Property

        Public Overrides Sub Initialize(ByVal component As System.ComponentModel.IComponent)
            MyBase.Initialize(component)

            Dim host As IDesignerHost = CType(GetService(GetType(IDesignerHost)), IDesignerHost)
            If host Is Nothing Then
                MessageBox.Show("The IDesignerHost service interface could not be obtained.")
                Return
            End If

            If MessageBox.Show("Press the Yes button to display notification message boxes for the designer transaction opened and closed notifications.", "Link DesignerTransaction Notifications?", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1, MessageBoxOptions.RightAlign) = DialogResult.Yes Then
                AddHandler host.TransactionOpened, AddressOf OnDesignerTransactionOpened
                AddHandler host.TransactionClosed, AddressOf OnDesignerTransactionClosed
                notification_mode = True
            End If
        End Sub

        Private Sub LinkDTNotifications(ByVal sender As Object, ByVal e As EventArgs)
            If notification_mode = False Then
                Dim host As IDesignerHost = CType(GetService(GetType(IDesignerHost)), IDesignerHost)
                If (host IsNot Nothing) Then
                    notification_mode = True
                    AddHandler host.TransactionOpened, AddressOf OnDesignerTransactionOpened
                    AddHandler host.TransactionClosed, AddressOf OnDesignerTransactionClosed
                End If
            End If
        End Sub

        Private Sub UnlinkDTNotifications(ByVal sender As Object, ByVal e As EventArgs)
            If notification_mode Then
                Dim host As IDesignerHost = CType(GetService(GetType(IDesignerHost)), IDesignerHost)
                If (host IsNot Nothing) Then
                    notification_mode = False
                    RemoveHandler host.TransactionOpened, AddressOf Me.OnDesignerTransactionOpened
                    RemoveHandler host.TransactionClosed, AddressOf Me.OnDesignerTransactionClosed
                End If
            End If
        End Sub

        Private Sub OnDesignerTransactionOpened(ByVal sender As Object, ByVal e As EventArgs)
            System.Windows.Forms.MessageBox.Show("A Designer Transaction was started. (TransactionOpened)")
        End Sub

        Private Sub OnDesignerTransactionClosed(ByVal sender As Object, ByVal e As DesignerTransactionCloseEventArgs)
            System.Windows.Forms.MessageBox.Show("A Designer Transaction was completed. (TransactionClosed)")
        End Sub

        Private Sub DoTransaction(ByVal sender As Object, ByVal e As EventArgs)
            Dim host As IDesignerHost = CType(GetService(GetType(IDesignerHost)), IDesignerHost)
            Dim t As DesignerTransaction = host.CreateTransaction("Change Text and Size")

            ' The code within the using statement is considered to be a single transaction.
            ' When the user selects Undo, the system will undo everything executed in this code block. 
            Try
                If (notification_mode) Then
                    System.Windows.Forms.MessageBox.Show("Entering a Designer-Initiated Designer Transaction")
                End If

                Dim someText As PropertyDescriptor = TypeDescriptor.GetProperties(Component)("StringProperty")
                someText.SetValue(Component, "This text was set by the designer for this component.")
                Dim anInteger As PropertyDescriptor = TypeDescriptor.GetProperties(Component)("CountProperty")
                anInteger.SetValue(Component, count)
                count = count + 1

                Exit Try
            Finally
                t.Commit()                
            End Try
            If (notification_mode) Then
                System.Windows.Forms.MessageBox.Show("Designer-Initiated Designer Transaction Completed")
            End If
        End Sub

        Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
            UnlinkDTNotifications(Me, New EventArgs())
            MyBase.Dispose(disposing)
        End Sub

    End Class
End Namespace 'DesignerTransactionSample

Commenti

Le transazioni possono tenere traccia delle azioni che possono essere annullate in un secondo momento.Transactions can track actions that can be undone later. Le modifiche apportate durante una transazione possono essere invertite annullando una transazione, che tenta automaticamente di annullare ogni modifica impostando ogni proprietà modificata sul valore precedente alla modifica.Changes made during a transaction can be reversed by canceling a transaction, which automatically attempts to reverse each change by setting each changed property to its pre-change value. Le transazioni possono inoltre migliorare le prestazioni durante una serie di operazioni rinviando gli aggiornamenti alla visualizzazione fino al completamento della transazione.Transactions can also improve performance during a series of operations by deferring updates to the display until the completion of the transaction.

Quando è in corso una transazione, alcuni componenti rinviano l'elaborazione fino a quando la transazione non viene completata TransactionOpening ascoltando gli eventi e TransactionClosed .When a transaction is in progress, some components defer their processing until the transaction has completed by listening to the TransactionOpening and TransactionClosed events. Il Finestra Proprietà, ad esempio, non aggiorna la visualizzazione dopo che una transazione è stata aperta fino a quando la transazione non è stata chiusa.The Properties window, for example, does not update its display after a transaction has opened until the transaction has closed.

Per usare le transazioni per operazioni reversibili o multiple, fare in modo che DesignerTransaction la finestra di progettazione crei un per ogni operazione o serie di operazioni che devono essere reversibili.To use transactions for reversible or multiple operations, have your designer create a DesignerTransaction for each operation or series of operations which should be reversible. Prestare attenzione a non eseguire azioni esterne alle transazioni che potrebbero impedire il corretto completamento di una sequenza di eventi di annullamento.Be careful not to perform actions outside the transactions that might prevent a sequence of undo events from completing successfully.

È possibile ottenere un nuovo DesignerTransaction chiamando il CreateTransaction metodo di un oggetto IDesignerHost.You can obtain a new DesignerTransaction by calling the CreateTransaction method of an IDesignerHost. Assicurarsi di ottenere ognuno DesignerTransaction di essi dall'oggetto attivo IDesignerHost per integrarsi correttamente con il meccanismo di elaborazione delle transazioni di progettazione, anziché creare DesignerTransaction direttamente un nuovo.Be sure to obtain each DesignerTransaction from the active IDesignerHost in order to correctly integrate with the designer transaction processing mechanism, rather than creating a new DesignerTransaction directly.

Per eseguire un'azione all'interno di una transazione, è necessario innanzitutto creare una transazione.To perform an action within a transaction, you must first create a transaction. È quindi necessario chiamare il OnComponentChanging metodo prima che venga eseguita ogni modifica o set di modifiche e OnComponentChanged il metodo dopo ogni modifica o set di modifiche.Then you must call the OnComponentChanging method before each change or set of changes occurs, and the OnComponentChanged method after each change or set of changes occur. Infine, completare e chiudere la transazione chiamando il Commit metodo.Finally, complete and close the transaction by calling the Commit method.

Nota

Quando si apportano modifiche ai valori delle SetValue proprietà, usare PropertyDescriptoril metodo di un oggetto, che chiama i IComponentChangeService metodi di modifica DesignerTransaction dei componenti di e crea un oggetto che rappresenta la modifica automaticamente.When making changes to property values, use the SetValue method of a PropertyDescriptor, which calls the component change methods of the IComponentChangeService and creates a DesignerTransaction representing the change automatically.

Per eseguire una transazione, completare i passaggi seguenti:To perform a transaction, complete the following steps:

  1. Chiamare CreateTransaction per ottenere un DesignerTransaction oggetto che può essere utilizzato per controllare la transazione.Call CreateTransaction to obtain a DesignerTransaction that can be used to control the transaction.

  2. All'interno try di un blocco, per ogni azione di cui si vuole tenere DesignerTransactiontraccia con un OnComponentChanging oggetto, chiamare il metodo, apportare la modifica o modificare OnComponentChanged , quindi chiamare il metodo per segnalare che la modifica o le modifiche sono state apportate.Within a try block, for each action that you want to track with a DesignerTransaction, call the OnComponentChanging method, make the change or changes, then call the OnComponentChanged method to signal that the change or changes have been made.

  3. Per completare la transazione, chiamare Commit dall'interno di finally un blocco.To complete the transaction, call Commit from within a finally block.

In C#è possibile utilizzare l' using istruzione anziché un try/finally blocco, ad esempio nell'esempio seguente.In C#, you can use the using statement rather than a try/finally block, such as in the following example.

using (host.CreateTransaction() {  
// Insert your code here.  
}  

Per annullare e tentare di eseguire il rollback di una transazione prima di eseguirne il commit Cancel , chiamare il metodo.To cancel and attempt to roll back a transaction before it has been committed, call the Cancel method. Quando viene Cancel richiamato il metodo, le azioni registrate DesignerTransaction da vengono invertite per tentare di eseguire il rollback delle modifiche.When the Cancel method is invoked, the actions tracked by the DesignerTransaction are reversed to attempt to roll back the changes. Per annullare le azioni che si sono verificate come parte delle transazioni precedenti, è necessario utilizzare il comando Annulla fornito dall'ambiente di sviluppo.To undo actions that occurred as part of earlier transactions, you must use the undo command provided by the development environment.

Costruttori

DesignerTransaction()

Inizializza una nuova istanza della classe DesignerTransaction senza descrizione.Initializes a new instance of the DesignerTransaction class with no description.

DesignerTransaction(String)

Inizializza una nuova istanza della classe DesignerTransaction utilizzando la descrizione della transazione specificata.Initializes a new instance of the DesignerTransaction class using the specified transaction description.

Proprietà

Canceled

Ottiene un valore che indica se la transazione è stata annullata.Gets a value indicating whether the transaction was canceled.

Committed

Ottiene un valore che indica se è stato eseguito il commit della transazione.Gets a value indicating whether the transaction was committed.

Description

Ottiene una descrizione relativa alla transazione.Gets a description for the transaction.

Metodi

Cancel()

Annulla la transazione e prova a ripristinare le modifiche apportate dagli eventi della transazione.Cancels the transaction and attempts to roll back the changes made by the events of the transaction.

Commit()

Esegue il commit di questa transazione.Commits this transaction.

Dispose(Boolean)

Rilascia le risorse non gestite usate da DesignerTransaction e, facoltativamente, le risorse gestite.Releases the unmanaged resources used by the DesignerTransaction and optionally releases the managed resources.

Equals(Object)

Determina se l'oggetto specificato è uguale all'oggetto corrente.Determines whether the specified object is equal to the current object.

(Ereditato da Object)
Finalize()

Libera le risorse associate all'oggetto.Releases the resources associated with this object. L'override consente di eseguire il commit della transazione se non è già stato eseguito.This override commits this transaction if it was not already committed.

GetHashCode()

Funge da funzione hash predefinita.Serves as the default hash function.

(Ereditato da Object)
GetType()

Ottiene l'oggetto Type dell'istanza corrente.Gets the Type of the current instance.

(Ereditato da Object)
MemberwiseClone()

Crea una copia superficiale dell'oggetto Object corrente.Creates a shallow copy of the current Object.

(Ereditato da Object)
OnCancel()

Genera l'evento Cancel.Raises the Cancel event.

OnCommit()

Esegue l'operazione effettiva di commit di una transazione.Performs the actual work of committing a transaction.

ToString()

Restituisce una stringa che rappresenta l'oggetto corrente.Returns a string that represents the current object.

(Ereditato da Object)

Implementazioni dell'interfaccia esplicita

IDisposable.Dispose()

Rilascia tutte le risorse usate da DesignerTransaction.Releases all resources used by the DesignerTransaction.

Sicurezza

NamedPermissionSet
per l'accesso completo alle risorse di sistema.for full access to system resources. Valore della richiesta InheritanceDemand:.Demand value: InheritanceDemand. Stato associato:Associated state:

Si applica a

Vedi anche