SQL Server中SMO备份数据库进度条不显示？

有朋友提到一个奇怪的问题，用SMO备份数据库时不显示进度条，也就是进度条事件PercentComplete不触发。

今天试了一下，果然有点奇怪。

代码如下：

 using Microsoft.SqlServer.Management.Smo;
using Microsoft.SqlServer.Management.Common;
private void btnBackup_Click(object sender, EventArgs e)
        {
            btnBackup.Enabled = false;
            Thread tr = new Thread(new ThreadStart(doBackup));
            tr.Priority = ThreadPriority.AboveNormal;
            tr.Start();
            //Thread.Sleep(3000);
        }
        /// <summary>
        /// 备份数据库
        /// </summary>
        public void doBackup()
        {
            pbDemo.Value = 0;
            pbDemo.Maximum = 100;
            pbDemo.Style = ProgressBarStyle.Blocks;
            //pbDemo.Step = 10;
            Server srv = new Server(@"(local)");
            Backup backup = new Backup();
            backup.Action = BackupActionType.Database;
            backup.Database = "btnet";
            backup.Incremental = false;
            backup.Devices.Add(new BackupDeviceItem(@"C:/agronet09.bak", DeviceType.File));
            backup.Initialize = true;
            backup.PercentCompleteNotification = 10;
            backup.PercentComplete += new PercentCompleteEventHandler(backup_PercentComplete);
            //backup.Checksum = true;
            backup.SqlBackup(srv);
        }
        public void backup_PercentComplete(object sender, Microsoft.SqlServer.Management.Smo.PercentCompleteEventArgs e)
        {
            this.Invoke(new displayProgress_delegate(displayProgress), e.Percent);
            //Application.DoEvents();
        }
        public delegate void displayProgress_delegate(int progress);
        public void displayProgress(int progress)
        {
            this.lbProgress.Text = "已完成[" + progress.ToString() + " %]";
            pbDemo.Value = progress;
            btnBackup.Enabled = (progress == 100);
        }

症状如下：结果正确执行，但进度条不显示。

刚开始以为是线程问题，后来发现不是这个原因。

又试了另外一段代码

using Microsoft.SqlServer.Management.Smo;
using Microsoft.SqlServer.Management.Common;
using System.Diagnostics;
  static void Main(string[] args)
        {
            BackupDatabase("ap4//agronet09", "agronet2008", "c://Northind_3.bak");
            Console.WriteLine(Environment.NewLine + "Press any key to continue.");
            Console.ReadKey();
        }
        public static  void BackupDatabase(string serverName, string databaseName, string fileName)
        {
            Console.WriteLine("*** Backing up ***");
            Server server = new Server(serverName);
            Backup backup = new Backup();
            backup.Action = BackupActionType.Database;
            backup.Database = databaseName;
            backup.Incremental = false;
            backup.Initialize = true;
            backup.LogTruncation = BackupTruncateLogType.Truncate;
            BackupDeviceItem backupItemDevice = new BackupDeviceItem(fileName, DeviceType.File);
            backup.Devices.Add(backupItemDevice);
            backup.PercentCompleteNotification = 10;
            backup.PercentComplete += backup_PercentComplete;
            backup.Complete +=backup_Complete;
            backup.SqlBackup(server);
        }
        protected static  void backup_PercentComplete(object sender, PercentCompleteEventArgs e)
        {
            Console.WriteLine(e.Percent + "% processed.");
            //Application.();
            System.Threading.Thread.Sleep(1000);
        }
        protected static  void backup_Complete(object sender, ServerMessageEventArgs e)
        {
            Console.WriteLine(Environment.NewLine + e.ToString());
        }

结果还是不显示。

后来突然想到会不会是文件太小，试了一个200M的数据文件，果然成功显示：

后来经反复实验，发现SQL server 2000约在数据文件加日志文件大于6M左右时显示进度条。

而Sql server 2008 r2大约在3M时显示进度条。可能跟机器也有关系。

注意：SQL server 2008 r2版规定主数据文件必须大于3M，微软真牛！

参考文章：

http://msdn.microsoft.com/zh-cn/magazine/cc163409.aspx

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