C#数据库备份、还原

以下是引用片段：

private void 备份数据库ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("确定要备份数据库吗？", "提示框", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
            {
                saveFileDialog1.Filter = "数据库文件|*.bak";
                if (saveFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    string path = saveFileDialog1.FileName;
                    if (File.Exists(path))
                    {
                        File.Delete(path);//注意，这个步骤很重要，如果重复，在备份的数据，就会变成，

                        //你刚开始的数据,所以每次都要先删除．

                    }
                    if (!File.Exists(path))
                    {
                        FileStream fs = File.Create(path);

                        fs.Close();
                    }
                    string backupstr = "backup database StuBody to disk='" + path + "';";
                    SqlConnection sql = new SqlConnection(Stu_add.Sqlstr);
                    SqlCommand sqlc = new SqlCommand(backupstr, sql);
                    try
                    {
                        sql.Open();
                        sqlc.ExecuteNonQuery();
                        MessageBox.Show("备份成功！");
                        sql.Close();

                    }
                    catch (Exception ex)
                    {
                        string stringError = ex.ToString();
                        MessageBox.Show("备份失败！");
                        sql.Close();
                    }
                }

            }
        }

以下是引用片段：

private void 还原数据库ToolStripMenuItem_Click(object sender, EventArgs e)
        {

            if (MessageBox.Show("确定要还原数据库吗？", "提示框", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
            {
                openFileDialog1.Filter = "数据库文件|*.bak";
                if (openFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    string path = openFileDialog1.FileName;
                    SqlConnection sql = new SqlConnection(Stu_add.Sqlstr);
                    string backupstr = "use master ";
                    string s1 = "ALTER DATABASE StuBody SET OFFLINE WITH ROLLBACK IMMEDIATE";
                    string s2 = "Restore Database StuBody From disk='" + path + "' with REPLACE";
                    string s3 = "ALTER DATABASE StuBody SET ONLINE WITH ROLLBACK IMMEDIATE";
                    try
                    {
                        SqlCommand sqlc = new SqlCommand(backupstr, sql);
                        sql.Open();

                        sqlc.ExecuteNonQuery();
                        sqlc = new SqlCommand(s1, sql);
                        sqlc.ExecuteNonQuery();
                        sqlc = new SqlCommand(s2, sql);
                        sqlc.ExecuteNonQuery();
                        sqlc = new SqlCommand(s3, sql);
                        sqlc.ExecuteNonQuery();
                        MessageBox.Show("恢复成功！");
                        sql.Close();
                    }
                    catch (Exception ex)
                    {
                        string stringError = ex.ToString();
                        MessageBox.Show("恢复失败！");
                        sql.Close();
                    }
                }
            }

        }