VB.NET中处理COM事件的问题

Question

我从VB.NET调用SQLDMO8.0COM库(使用使用tlbimp生成的PIA )，以便使用百分比完成通知备份数据库：

Dim server As SQLDMO.SQLServer = Nothing
Dim backup As SQLDMO.Backup = Nothing
Dim restore As SQLDMO.Restore = Nothing
Dim backupAbortable As Boolean
Dim restoreAbortable As Boolean
Try
    server = New SQLDMO.SQLServer
    server.LoginSecure = True
    server.Connect(serverName)

    backup = New SQLDMO.Backup
    backup.Action = SQLDMO.SQLDMO_BACKUP_TYPE.SQLDMOBackup_Database
    backup.BackupSetDescription = "test"
    backup.BackupSetName = "test"
    backup.Database = databaseName
    backup.Files = TransactSqlName.Delimit(fileName)
    backup.TruncateLog = SQLDMO.SQLDMO_BACKUP_LOG_TYPE.SQLDMOBackup_Log_Truncate
    backup.PercentCompleteNotification = 1
    AddHandler backup.PercentComplete, AddressOf OnOperationPercentComplete
    AddHandler backup.NextMedia, AddressOf OnOperationNextMedia
    AddHandler backup.Complete, AddressOf OnOperationComplete
    backupAbortable = True
    backup.SQLBackup(server)
    backupAbortable = False

    restore = New SQLDMO.Restore
    restore.Files = backup.Files
    AddHandler restore.PercentComplete, AddressOf OnOperationPercentComplete
    AddHandler restore.NextMedia, AddressOf OnOperationNextMedia
    AddHandler restore.Complete, AddressOf OnOperationComplete
    restoreAbortable = True
    restore.SQLVerify(server)
    restoreAbortable = False

    server.DisConnect()
Catch ex As AbortException
    If backupAbortable Then
        backup.Abort()
    End If
    If restoreAbortable Then
        restore.Abort()
    End If
Finally
    If restore IsNot Nothing Then
        RemoveHandler restore.PercentComplete, AddressOf OnOperationPercentComplete
        RemoveHandler restore.NextMedia, AddressOf OnOperationNextMedia
        RemoveHandler restore.Complete, AddressOf OnOperationComplete
        Marshal.FinalReleaseComObject(restore)
        restore = Nothing
    End If
    If backup IsNot Nothing Then
        RemoveHandler backup.PercentComplete, AddressOf OnOperationPercentComplete
        RemoveHandler backup.NextMedia, AddressOf OnOperationNextMedia
        RemoveHandler backup.Complete, AddressOf OnOperationComplete
        Marshal.FinalReleaseComObject(backup)
        backup = Nothing
    End If
    If server IsNot Nothing Then
        Marshal.FinalReleaseComObject(server)
        server = Nothing
    End If
End Try

除了事件处理程序之外，这很好--只有第一个连接起来的处理程序才会实际执行。我不能肯定地说NextMedia事件，因为它只为磁带备份触发，但是对于另外两个事件，我要么得到完整的事件，要么根据AddHandler语句的顺序得到PercentComplete事件触发，而不是两者同时发生。

可能性：

我所做的一切都是错误的(建议在SQLDMO8.0中welcome!)

• There's一个bug，它实际上只触发events.

• There's中的一个- RCW中的一个bug或影响COM互操作事件的VB.NET编译器。

)

有什么想法吗？

Answer 1

这在VB.NET 2005中是可行的，不确定在1.1左右。

我知道您已经在COM互操作上做了大量的工作，但是您能不能直接使用Info来连接

注意STATS = 10.这意味着每10%发出进度通知。

这只是我一直在做的一个项目的一个片段，我希望你能从中得到你需要的东西。

public sub Backup()
  Dim Conn As SqlClient.SqlConnection
  dim theCommand as SqlClient.SQLCommand
  Conn = New SqlClient.SqlConnection("Data Source=.\MyInstance;Initial Catalog=Master;Integrated Security=SSPI;")
  theCommand = Conn.CreateCommand

  theCommand.CommandText = "BACKUP DATABASE [MyDatabase] TO DISK = '" & mDatabasePath & "\" & Filenames.SQLBackup & "' WITH NOFORMAT, INIT, NAME = 'MyDatabase-Full Database Backup', SKIP, NOREWIND, NOUNLOAD, STATS = 10"

  AddHandler Conn.InfoMessage, AddressOf onSqlInfoMessage
  'make sure the events are fired as they are available, instead of at the end.
  Conn.FireInfoMessageEventOnUserErrors = True

  Conn.Open()

  theCommand.ExecuteNonQuery()
      RemoveHandler Conn.InfoMessage, AddressOf onSqlInfoMessage

  Conn.Close()

end sub 

   Private Sub onSqlInfoMessage(ByVal sender As Object, ByVal args As SqlClient.SqlInfoMessageEventArgs)
        If args.Message.EndsWith("percent processed.") Then
            Dim theMatch As System.Text.RegularExpressions.Match
            theMatch = mRegEx.Match(args.Message)
            debug.print("Progress = " & theMatch.Value.Trim)
        End If
    End Sub