string restoreSql = "use master;";
    restoreSql += "restore database @dbname from disk = @path;";
                string pai = "use master;ALTER DATABASE Wy SET OFFLINE WITH ROLLBACK IMMEDIATE;ALTER DATABASE Wy SET ONLINE WITH ROLLBACK IMMEDIATE";
                SqlConnection conn = new SqlConnection(ConnStr);
                SqlCommand com1 = new SqlCommand(pai, conn);

    SqlCommand myCommand = new SqlCommand(restoreSql, new SqlConnection(ConnStr));

    myCommand.Parameters.Add("@dbname", SqlDbType.Char);
    myCommand.Parameters["@dbname"].Value = dbname;
    myCommand.Parameters.Add("@path", SqlDbType.Char);
    myCommand.Parameters["@path"].Value = path;

    try
    {
                    conn.Open();
                    com1.ExecuteNonQuery();
                    conn.Close();
                    myCommand.Connection.Open();
     myCommand.ExecuteNonQuery();
                    infoLabel.Text = "恢复成功！<br>已经把备份"+path+"恢复到数据库";

    }
    catch(Exception ex)
    {
                    infoLabel.Text = "恢复失败！<br>出错信息如下：<br>" + ex.ToString();
    }
    finally
    {
     myCommand.Connection.Close();

    }
   }