DesignerTransaction 類別

定義

public ref class DesignerTransaction abstract : IDisposable

public abstract class DesignerTransaction : IDisposable

type DesignerTransaction = class
    interface IDisposable

Public MustInherit Class DesignerTransaction
Implements IDisposable

繼承

Object

DesignerTransaction

實作

IDisposable

範例

以下範例程式示範如何從設計器建立 。DesignerTransaction 要執行這個範例，請將原始碼編譯成類別函式庫。 你必須在 System.Design 組件中加入參考。 在新專案中，新增已編譯 DLL 的參考，並將函式庫中的元件加入 工具箱。

Visual Studio 對此功能有廣泛的支援。

另請參閱 攻略：自動填充工具箱自訂元件。

設計器可選擇性地顯示有關設計者交易事件的通知。 如果你在設計模式下將 的實例 DTComponent 加入表單，會出現一個訊息框詢問你是否想要接收設計師交易事件通知。 你可以透過右鍵點擊 DTComponent. 交易是在你使用 屬性視窗 更改值時產生的。 你也可以讓設計師在元件的快捷鍵選單中點擊 「執行範例交易 」來執行交易。

#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)
            {
            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

備註

交易可以追蹤那些日後可以被撤銷的行動。 交易過程中所做的變更可以透過取消交易來逆轉，該交易會自動嘗試將每個變更的屬性設為變更前的值來逆轉。 交易也能透過延後顯示更新直到交易完成來提升操作效能。

當交易進行中時，部分元件會透過監聽 TransactionOpening and TransactionClosed 事件來延遲處理直到交易完成。 例如，屬性視窗 在交易開啟後，直到交易結束前不會更新顯示。

若要使用交易進行可逆或多重操作，請設計者為每個操作或一系列操作建立 DesignerTransaction 一個應可逆的交易。 請小心不要在交易之外執行可能阻止一連串復原事件成功完成的操作。

你可以透過呼叫 的方法CreateTransactionIDesignerHost來獲得 新 DesignerTransaction 。 務必從主動IDesignerHost者取得每個DesignerTransaction機制，才能正確整合到設計者的交易處理機制，而不是直接建立新的DesignerTransaction。

要在交易中執行動作，必須先建立交易。 接著你必須在每次變更或一組變更發生前呼叫該 OnComponentChanging 方法，以及每次變更或一組變更發生後的方法 OnComponentChanged 。 最後，透過呼叫 Commit 該方法完成並結束交易。

執行交易時，請完成以下步驟：

1. 呼叫 CreateTransaction 以獲得 DesignerTransaction 可用來控制交易的 。

2. 在一個 try 區塊內，對於你想用一個動作追蹤 DesignerTransaction，呼叫該 OnComponentChanging 方法，進行變更，然後呼叫 OnComponentChanged 該方法來表示變更已完成。

3. 要完成交易，請在區finally塊內呼叫Commit。

在 C# 中，你可以使用 using 陳述句代替 try/finally 區塊，例如以下範例。

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

若要取消並嘗試回滾交易，請呼叫該 Cancel 方法。 當 Cancel 方法被呼叫時，追蹤的 DesignerTransaction 動作會被反轉，以嘗試回滾變更。 要撤銷先前交易中發生的操作，必須使用開發環境提供的復原指令。

另請參閱

• IDesignerHost
• IComponentChangeService
• PropertyDescriptor