Como sincronizar dados de forma assíncrona (programaticamente)
Neste tópico, você aprenderá como sincronizar uma assinatura de forma assíncrona usando a classe SqlCeReplication. A sincronização de dados assíncronos permite que o aplicativo execute outras ações durante a sincronização. Para obter mais informações sobre como usar o namespace SqlServerCe, consulte a documentação de referência de namespaces do SqlServerCe.
Para iniciar a sincronização de dados assíncronos
Inicialize um objeto SqlCeReplication. Declare o objeto fora de qualquer método para que ele possa ser acessado.
private SqlCeReplication repl;No método que inicia a sincronização, crie uma instância do objeto SqlCeReplication e defina as propriedades necessárias para a sincronização com um 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";Chame o método BeginSynchronize. Isso retorna um objeto IAsyncResult. Ao chamar BeginSynchronize, passe um manipulador de eventos AsyncCallback e o objeto SqlCeReplication. O evento AsyncCallback será acionado quando a sincronização for concluída. Você também pode passar manipuladores de eventos para os eventos OnStartTableUpload, OnStartTableDownload e OnSynchronization.
IAsyncResult ar = repl.BeginSynchronize (new syncCallback(this.SyncCompletedCallback), new OnStartTableUpload(this.OnStartTableUploadCallback), new OnStartTableDownload(this.OnStartTableDownloadCallback), new OnSynchronization(this.OnSynchronizationCallback), repl);
Para manipular eventos de sincronização:
O único evento necessário somente é AsyncCallback, que leva IAsyncResult como seu único parâmetro.
public void SyncCompletedCallback(IAsyncResult ar) { ... }Os manipuladores de eventos OnStartTableUpload e OnStartTableDownload levam IAsyncResult e o nome da tabela (como uma cadeia de caracteres) como parâmetros.
public void OnStartTableUploadCallback(IAsyncResult ar, string tableName) { ... } public void OnStartTableDownloadCallback(IAsyncResult ar,string tableName) { ... }O manipulador de eventos OnSynchronization leva IAsyncResult e um inteiro que representa a porcentagem da sincronização que foi concluída como parâmetros.
public void OnSynchronizationCallback(IAsyncResult ar, int percentComplete) { ... }
Para encerrar a sincronização de dados assíncronos
No manipulador de eventos AsyncCallback, use o objeto SqlCeReplication passado e o objeto IAsyncResult para chamar o método EndSynchronize.
SqlCeReplication repl = (SqlCeReplication)ar.AsyncState; repl.EndSynchronize(ar);
Exemplo
Este exemplo mostra como implementar a sincronização de dados assíncronos. Neste exemplo, o aplicativo usa o SyncStatus para atualizar a interface do usuário durante a sincronização de forma que o usuário tenha ciência do andamento. A interface do usuário é atualizada sempre que um evento de sincronização é acionado e sempre que uma tabela é carregada e baixada. Quando a sincronização é concluída, o aplicativo obtém a hora da última sincronização bem-sucedida da tabela __sysMergeSubscriptions e exibe os 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
Consulte também
Outros recursos
Sincronização de dados assíncronos
Usando a replicação de mesclagem