C# 使用SQLDMO备份数据库时不显示进度的问题解决方法

在使用SQLDMO备份数据库的过程中，参考了网上的例子，但是进度条却不显示，每次返回的都是0，解决方法是使用全局变量，每次做个累加就可以了。

        string ServerName = "";
        string UserName = "sa";//暂时锁定，可以根据需要自己设置
        string Password = "sa";
        string DataPath = "E:\\数据库备份\\"; //数据库备份路径
        bool successFlag = false;  //备份是否成功的标志
        int step = 1;  //进度条

        private void Form1_Load(object sender, EventArgs e)
        {
            CheckForIllegalCrossThreadCalls = false;
        }



        //获取数据库列表
        public ArrayList GetDbList(string strServerName, string strUserName, string strPwd)
        {
            string ServerName = strServerName;
            string UserName = strUserName;
            string Password = strPwd;

            ArrayList alDbs = new ArrayList();
            SQLDMO.Application sqlApp = new SQLDMO.ApplicationClass();
            SQLDMO.SQLServer svr = new SQLDMO.SQLServerClass();
            try
            {
                svr.Connect(ServerName, UserName, Password);
                foreach (SQLDMO.Database db in svr.Databases)
                {
                    if (db.Name != null)
                        alDbs.Add(db.Name);
                    L_data.Items.Add(db.Name);
                }
            }
            catch (Exception e)
            {
                MessageBox.Show("连接数据库出错：" + e.Message);
            }
            finally
            {
                svr.DisConnect();
                sqlApp.Quit();
            }
            return alDbs;
        }

        //备份数据
        public bool BackUPDB(string strDbName, string strFileName, ProgressBar pgbMain)
        {
            ProgressBar PBar = pgbMain;
            SQLDMO.SQLServer svr = new SQLDMO.SQLServerClass();
            try
            {
                svr.Connect(ServerName, UserName, Password);
                SQLDMO.Backup bak = new SQLDMO.BackupClass();
                bak.Action = 0;
                bak.Initialize = true;
                SQLDMO.BackupSink_PercentCompleteEventHandler pceh = new SQLDMO.BackupSink_PercentCompleteEventHandler(Step);
                bak.PercentComplete += pceh;
                bak.Files = strFileName;//这里可以写成路径+文件名形式，自己写！
                bak.Database = strDbName;
                bak.SQLBackup(svr);
                L1.Items.Add(DateTime.Now.ToShortDateString() + " 数据库备份完成，位置为：" + strFileName);
                PBar.Value = 0;
                successFlag = true;
                return true;
            }
            catch (Exception err)
            {
                throw (new Exception("备份数据库失败" + err.Message));
                L1.Items.Add(DateTime.Now.ToShortDateString() + " 数据库备份失败！");
            }
            finally
            {
                svr.DisConnect();
            }
        }
        //进度条,precent返回值是0，备份完成会返回10次，所以这里用step来计数，然后乘10给进度条
        private void Step(string message, int percent)
        {
            
            PBar.Value = step*10;  
            step += 1;
        }

        private void btn_load_Click(object sender, EventArgs e)
        {
            //显示数据库
            ServerName = txt_IP.Text.Trim().ToString();
            UserName = txt_user.Text.Trim().ToString();
            Password = txt_pass.Text.Trim().ToString();
            

            if (UserName.Length < 2) 
            {
                MessageBox.Show("请输入正确的数据库用户名");
                return;
            }
            if (Password.Length < 1)
            {
                MessageBox.Show("请输入正确的数据库密码,不支持空密码输入");
                return;
            }
            GetDbList(ServerName, UserName, Password);


            //检查备份路径是否存在
            try
            {
                if (!Directory.Exists(DataPath))
                {
                    DirectoryInfo di = Directory.CreateDirectory(DataPath);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("创建目录失败：{0}", ex.ToString());
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //备份数据库
            string DataName = L_data.SelectedItem.ToString();
            string Filename = DataPath + DataName + "_" + DateTime.Now.ToShortDateString();

            L1.Items.Add(DateTime.Now.ToShortDateString() + " 选择了"+DataName+"进行备份！");
            successFlag = false;
            step = 1;

            Thread t1 = new Thread(() => BackUPDB(DataName, Filename, PBar));
            t1.IsBackground = true;
            t1.Start();
            

            
            
        }