本文数据库的名称为ProjectControl
  public static SqlConnection conn = new SqlConnection("server=(local);uid=sa;pwd=000;database=ProjectControl");
//备份        public bool BackUpDataBase(string databasefile)        {            if (!File.Exists(databasefile))            {            }            //还原的数据库MyDataBase            string sql = "BACKUP DATABASE " + "ProjectControl" + " TO DISK = ‘" + databasefile + ".bak‘ ";            conn.Open();            SqlCommand comm = new SqlCommand(sql, conn);            comm.CommandType = CommandType.Text;            try            {                comm.ExecuteNonQuery();            }            catch (Exception err)            {                string str = err.Message;                MessageBox.Show(str);                conn.Close();                return false;            }            MessageBox.Show("备份成功");            conn.Close();//关闭数据库连接            return true;        }        //还原        public string RestoreDatabase(string backfile)        {            ///杀死原来所有的数据库连接进程            SqlConnection conn = new SqlConnection();            conn.ConnectionString = "Data Source=.;Initial Catalog=master;User ID=sa;pwd =000";            conn.Open();            string sql = "SELECT spid FROM sysprocesses ,sysdatabases WHERE sysprocesses.dbid=sysdatabases.dbid AND sysdatabases.Name=‘" +                          "ProjectControl" + "‘";            SqlCommand cmd1 = new SqlCommand(sql, conn);            SqlDataReader dr;            ArrayList list = new ArrayList();            try            {                dr = cmd1.ExecuteReader();                while (dr.Read())                {                    list.Add(dr.GetInt16(0));                }                dr.Close();            }            catch (SqlException eee)            {                MessageBox.Show(eee.ToString());            }            finally            {                conn.Close();            }            //MessageBox.Show(list.Count.ToString());            for (int i = 0; i < list.Count; i++)            {                conn.Open();                cmd1 = new SqlCommand(string.Format("KILL {0}", list[i].ToString()), conn);                cmd1.ExecuteNonQuery();                conn.Close();                //MessageBox.Show("系统已经清除的数据库线程： " + list[i].ToString() + "\r\n正在还原数据库！");            }            //这里一定要是master数据库，而不能是要还原的数据库，因为这样便变成了有其它进程            //占用了数据库。            string constr = @"Data Source=.;Initial Catalog=master;User ID=sa;pwd =tc0001";            string database = "ProjectControl";            string path = backfile;            string BACKUP = String.Format("RESTORE DATABASE {0} FROM DISK = ‘{1}‘ WITH REPLACE", database, path);            SqlConnection con = new SqlConnection(constr);            SqlCommand cmd = new SqlCommand(BACKUP, con);            con.Open();            try            {                cmd.ExecuteNonQuery();                MessageBox.Show("还原成功,点击退出系统！");                Application.Exit();            }            catch (SqlException ee)            {                //throw(ee);                //MessageBox.Show("还原失败");                MessageBox.Show(ee.ToString());            }            finally            {                con.Close();            }            return "成功与否字符串";        }