Cómo sincronizar datos de forma asincrónica (mediante programación)
En este tema aprenderá a sincronizar una suscripción de forma asincrónica mediante la clase SqlCeReplication. La sincronización de datos asincrónica permite que su aplicación realice otras acciones mientras tiene lugar la sincronización. Para obtener más información sobre cómo usar el espacio de nombres SqlServerCe, consulte la documentación de referencia sobre el espacio de nombres SqlServerCe.
Para iniciar una sincronización de datos asincrónica
Inicialice un objeto SqlCeReplication. Debe declarar el objeto fuera de cualquier método para que sea accesible.
private SqlCeReplication repl;En el mismo método que inicia la sincronización, cree una instancia del objeto SqlCeReplication y, a continuación, establezca las propiedades necesarias para realizar la sincronización con un publicador.
this.repl = new SqlCeReplication(); repl.InternetUrl = "https://www.adventure-works.com/sqlmobile/sqlcesa35.dll"; repl.InternetLogin = "MyInternetLogin"; repl.InternetPassword = "<password>"; repl.Publisher = "MyPublisher"; repl.PublisherDatabase = "MyPublisherDatabase"; repl.PublisherLogin = "MyPublisherLogin"; repl.PublisherPassword = "<password>"; repl.Publication = "MyPublication"; repl.Subscriber = "MySubscriber"; repl.SubscriberConnectionString = "Data Source=MyDatabase.sdf";Llame al método BeginSynchronize. Esta acción devolverá un objeto IAsyncResult. Cuando se llama al método BeginSynchronize, se debe enviar un controlador de eventos AsyncCallback y el objeto SqlCeReplication. El evento AsyncCallback se desencadena cuando se completa la sincronización. También puede enviar controladores de eventos para los eventos OnStartTableUpload, OnStartTableDownload y OnSynchronization.
IAsyncResult ar = repl.BeginSynchronize (new syncCallback(this.SyncCompletedCallback), new OnStartTableUpload(this.OnStartTableUploadCallback), new OnStartTableDownload(this.OnStartTableDownloadCallback), new OnSynchronization(this.OnSynchronizationCallback), repl);
Para controlar eventos de sincronización:
El único evento obligatorio es AsyncCallback, que toma a IAsyncResult como su único parámetro.
public void SyncCompletedCallback(IAsyncResult ar) { ... }Los controladores de eventos OnStartTableUpload y OnStartTableDownload toman a IAsyncResult y al nombre de tabla (como una cadena) como parámetros.
public void OnStartTableUploadCallback(IAsyncResult ar, string tableName) { ... } public void OnStartTableDownloadCallback(IAsyncResult ar,string tableName) { ... }El controlador de eventos OnSynchronization toma a IAsyncResult y a un entero que representa el porcentaje de sincronización completada como parámetros.
public void OnSynchronizationCallback(IAsyncResult ar, int percentComplete) { ... }
Para finalizar una sincronización de datos asincrónica
En el controlador de eventos AsyncCallback, use los objetos enviados SqlCeReplication y IAsyncResult para llamar al método EndSynchronize.
SqlCeReplication repl = (SqlCeReplication)ar.AsyncState; repl.EndSynchronize(ar);
Ejemplo
En el ejemplo siguiente se muestra cómo implementar la sincronización de datos de forma asincrónica. En este ejemplo, la aplicación usa SyncStatus para actualizar la interfaz de usuario durante la sincronización a fin de que el usuario conozca el progreso de la misma. La interfaz de usuario se actualiza siempre que se desencadena un evento de sincronización y siempre que se carga y descarga una tabla. Una vez se ha completado la sincronización, la aplicación obtiene la hora de la última sincronización llevada a cabo correctamente desde la tabla __sysMergeSubscriptions y muestra los resultados.
public class MyForm : Form
{
private string tableName;
private int percentage;
private SyncStatus eventStatus;
private SqlCeReplication repl;
private EventHandler myUserInterfaceUpdateEvent;
internal enum SyncStatus
{
PercentComplete,
BeginUpload,
BeginDownload,
SyncComplete
}
public MyForm()
{
// InitializeComponent();
this.myUserInterfaceUpdateEvent = new EventHandler(MyUserInterfaceUpdateEvent);
}
public void MyUserInterfaceUpdateEvent(object sender, System.EventArgs e)
{
switch (this.eventStatus)
{
case SyncStatus.BeginUpload:
//this.labelStatusValue.Text = "Began uploading table : " + tableName;
break;
case SyncStatus.PercentComplete:
//this.labelStatusValue.Text = "Sync with SQL Server is " + percentage.ToString() + "% complete.";
break;
case SyncStatus.BeginDownload:
//this.labelStatusValue.Text = "Began downloading table : " + tableName;
break;
case SyncStatus.SyncComplete:
//this.labelStatusValue.Text = "Synchronization has completed successfully";
//this.labelLastSyncValue.Text = GetLastSuccessfulSyncTime().ToString();
break;
}
}
public void SyncCompletedCallback(IAsyncResult ar)
{
try
{
SqlCeReplication repl = (SqlCeReplication)ar.AsyncState;
repl.EndSynchronize(ar);
repl.SaveProperties();
this.eventStatus = SyncStatus.SyncComplete;
}
catch (SqlCeException e)
{
MessageBox.Show(e.Message);
}
finally
{
// NOTE: If you want to set Control properties from within this
// method, you must use Control.Invoke method to marshal
// the call to the UI thread; otherwise you might deadlock your
// application; See Control.Invoke documentation for more information
//
this.Invoke(this.myUserInterfaceUpdateEvent);
}
}
public void OnStartTableUploadCallback(IAsyncResult ar, string tableName)
{
this.tableName = tableName;
this.eventStatus = SyncStatus.BeginUpload;
// NOTE: If you want to set Control properties from within this
// method, you must use Control.Invoke method to marshal
// the call to the UI thread; otherwise you might deadlock your
// application; See Control.Invoke documentation for more information
//
this.Invoke(this.myUserInterfaceUpdateEvent);
}
public void OnSynchronizationCallback(IAsyncResult ar, int percentComplete)
{
this.percentage = percentComplete;
this.eventStatus = SyncStatus.PercentComplete;
// NOTE: If you want to set Control properties from within this
// method, you must use Control.Invoke method to marshal
// the call to the UI thread; otherwise you might deadlock your
// application; See Control.Invoke documentation for more information
//
this.Invoke(this.myUserInterfaceUpdateEvent);
}
public void OnStartTableDownloadCallback(IAsyncResult ar, string tableName)
{
this.tableName = tableName;
this.eventStatus = SyncStatus.BeginDownload;
// NOTE: If you want to set Control properties from within this
// method, you must use Control.Invoke method to marshal
// the call to the UI thread; otherwise you might deadlock your
// application; See Control.Invoke documentation for more information
//
this.Invoke(this.myUserInterfaceUpdateEvent);
}
private void ButtonSynchronize_Click(object sender, System.EventArgs e)
{
try
{
this.repl = new SqlCeReplication();
repl.SubscriberConnectionString = "Data Source=Test.sdf";
if (false == File.Exists("Test.sdf"))
{
repl.AddSubscription(AddOption.CreateDatabase);
repl.PublisherSecurityMode = SecurityType.DBAuthentication;
repl.Publisher = "MyPublisher";
repl.PublisherLogin = "PublisherLogin";
repl.PublisherPassword = "<Password>";
repl.PublisherDatabase = "AdventureWorksDW";
repl.Publication = "AdventureWorksDW";
repl.InternetUrl = "https://www.adventure-works.com/sqlmobile/sqlcesa35.dll";
repl.InternetLogin = "MyInternetLogin";
repl.InternetPassword = "<Password";
repl.Subscriber = "MySubscriber";
}
else
{
repl.LoadProperties();
}
IAsyncResult ar = repl.BeginSynchronize(
new AsyncCallback(this.SyncCompletedCallback),
new OnStartTableUpload(this.OnStartTableUploadCallback),
new OnStartTableDownload(this.OnStartTableDownloadCallback),
new OnSynchronization(this.OnSynchronizationCallback),
repl);
}
catch (SqlCeException ex)
{
MessageBox.Show(ex.Message);
}
}
public DateTime GetLastSuccessfulSyncTime()
{
DateTime localDateTime;
SqlCeConnection conn = null;
SqlCeCommand cmd = null;
try
{
conn = new SqlCeConnection("Data Source = Test.sdf");
conn.Open();
cmd = conn.CreateCommand();
cmd.CommandText = "SELECT LastSuccessfulSync FROM __sysMergeSubscriptions " +
"WHERE Publication=@publication";
cmd.Parameters.Add("@publication", SqlDbType.NVarChar, 4000);
cmd.Parameters["@publication"].Value = "AdventureWorksDW";
//Note: LastSuccessfulSync is stored in local time, not UTC time
localDateTime = (DateTime)cmd.ExecuteScalar();
return localDateTime;
}
finally
{
conn.Close();
}
}
}
Public Class MyForm
Inherits Form
Private myUserInterfaceUpdateEvent As EventHandler
Private tableName As String
Private percentage As Integer
Private eventStatus As SyncStatus
Private repl As SqlCeReplication
Friend Enum SyncStatus
PercentComplete
BeginUpload
BeginDownload
SyncComplete
End Enum 'SyncStatus
Public Sub New()
' InitializeComponent();
Me.myUserInterfaceUpdateEvent = New EventHandler(AddressOf UserInterfaceUpdateEvent)
End Sub 'New
Public Sub UserInterfaceUpdateEvent(ByVal sender As Object, ByVal e As System.EventArgs)
Select Case Me.eventStatus
Case SyncStatus.BeginUpload
'this.labelStatusValue.Text = "Began uploading table : " & tableName;
Case SyncStatus.PercentComplete
'this.labelStatusValue.Text = "Sync with SQL Server is " & percentage.ToString() & "% complete.";
Case SyncStatus.BeginDownload
'this.labelStatusValue.Text = "Began downloading table : " & tableName;
Case SyncStatus.SyncComplete
'this.labelStatusValue.Text = "Synchronization has completed successfully";
'this.labelLastSyncValue.Text = GetLastSuccessfulSyncTime().ToString();
End Select
End Sub 'UserInterfaceUpdateEvent
Public Sub SyncCompletedCallback(ByVal ar As IAsyncResult)
Try
Dim repl As SqlCeReplication = CType(ar.AsyncState, SqlCeReplication)
repl.EndSynchronize(ar)
repl.SaveProperties()
Me.eventStatus = SyncStatus.SyncComplete
Catch e As SqlCeException
MessageBox.Show(e.Message)
Finally
' NOTE: If you want to set Control properties from within this
' method, you must use Control.Invoke method to marshal
' the call to the UI thread; otherwise you might deadlock your
' application; See Control.Invoke documentation for more information
'
Me.Invoke(Me.myUserInterfaceUpdateEvent)
End Try
End Sub 'SyncCompletedCallback
Public Sub OnStartTableUploadCallback(ByVal ar As IAsyncResult, ByVal tableName As String)
Me.tableName = tableName
Me.eventStatus = SyncStatus.BeginUpload
' NOTE: If you want to set Control properties from within this
' method, you must use Control.Invoke method to marshal
' the call to the UI thread; otherwise you might deadlock your
' application; See Control.Invoke documentation for more information
'
Me.Invoke(Me.myUserInterfaceUpdateEvent)
End Sub 'OnStartTableUploadCallback
Public Sub OnSynchronizationCallback(ByVal ar As IAsyncResult, ByVal percentComplete As Integer)
Me.percentage = percentComplete
Me.eventStatus = SyncStatus.PercentComplete
' NOTE: If you want to set Control properties from within this
' method, you must use Control.Invoke method to marshal
' the call to the UI thread; otherwise you might deadlock your
' application; See Control.Invoke documentation for more information
'
Me.Invoke(Me.myUserInterfaceUpdateEvent)
End Sub 'OnSynchronizationCallback
Public Sub OnStartTableDownloadCallback(ByVal ar As IAsyncResult, ByVal tableName As String)
Me.tableName = tableName
Me.eventStatus = SyncStatus.BeginDownload
' NOTE: If you want to set Control properties from within this
' method, you must use Control.Invoke method to marshal
' the call to the UI thread; otherwise you might deadlock your
' application; See Control.Invoke documentation for more information
'
Me.Invoke(Me.myUserInterfaceUpdateEvent)
End Sub 'OnStartTableDownloadCallback
Private Sub ButtonSynchronize_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Try
Me.repl = New SqlCeReplication()
repl.SubscriberConnectionString = "Data Source=Test.sdf"
If False = File.Exists("Test.sdf") Then
repl.AddSubscription(AddOption.CreateDatabase)
repl.PublisherSecurityMode = SecurityType.DBAuthentication
repl.Publisher = "MyPublisher"
repl.PublisherLogin = "PublisherLogin"
repl.PublisherPassword = "<Password>"
repl.PublisherDatabase = "AdventureWorksDW"
repl.Publication = "AdventureWorksDW"
repl.InternetUrl = "https://www.adventure-works.com/sqlmobile/sqlcesa35.dll"
repl.InternetLogin = "InternetLogin"
repl.InternetPassword = "<Password>"
repl.Subscriber = "MySubscriber"
Else
repl.LoadProperties()
End If
Dim ar As IAsyncResult = repl.BeginSynchronize( _
New AsyncCallback(AddressOf Me.SyncCompletedCallback), _
New OnStartTableUpload(AddressOf Me.OnStartTableUploadCallback), _
New OnStartTableDownload(AddressOf Me.OnStartTableDownloadCallback), _
New OnSynchronization(AddressOf Me.OnSynchronizationCallback), repl)
Catch ex As SqlCeException
MessageBox.Show(ex.Message)
End Try
End Sub 'ButtonSynchronize_Click
Public Function GetLastSuccessfulSyncTime() As DateTime
Dim localDateTime As DateTime
Dim conn As SqlCeConnection = Nothing
Dim cmd As SqlCeCommand = Nothing
Try
conn = New SqlCeConnection("Data Source = Test.sdf")
conn.Open()
cmd = conn.CreateCommand()
cmd.CommandText = "SELECT LastSuccessfulSync FROM __sysMergeSubscriptions " & _
"WHERE Publication=@publication"
cmd.Parameters.Add("@publication", SqlDbType.NVarChar, 4000)
cmd.Parameters("@publication").Value = "AdventureWorksDW"
'Note: LastSuccessfulSync is stored in local time, not UTC time
localDateTime = CType(cmd.ExecuteScalar(), DateTime)
Return localDateTime
Finally
conn.Close()
End Try
End Function 'GetLastSuccessfulSyncTime
End Class 'MyForm