获取上次打开目录

路径简单保存到csv文件的方式，下次直接获取

public class FolderPathHelper
    {
        public static string GetLastPath(string user, string menu)
        {
            string currentPath = Directory.GetCurrentDirectory() + "\\UserPath\\LastPath.csv";

            if (!File.Exists(currentPath))
            {
                return "";
            }

            var table = OpenCSVFile(currentPath);
            var folder = table.AsEnumerable().FirstOrDefault(row => row["user"].ToString() == user && row["menu"].ToString() == menu)?["folder"].ToString() ?? "";
            return folder;
        }

        public static bool SavePath(string user, string menu, string folder)
        {
            //判断目录是否存在
            string currentPath = Directory.GetCurrentDirectory() + "\\UserPath\\LastPath.csv";
            DataTable table;

            table = OpenCSVFile(currentPath);
            if (table.Rows.Count > 0)
            {
                var rows = table.AsEnumerable().Where(row => row["user"].ToString() == user && row["menu"].ToString() == menu).ToList();
                foreach (var row in rows)
                {
                    table.Rows.Remove(row);
                }
            }           
            table.Rows.Add(user, menu, folder, DateTime.Now.ToString("yyyyMMdd hhmmss"));
            SaveCSV(table, currentPath);
            return true;
        }

        public static void SaveCSV(DataTable dt, string fullPath)//table数据写入csv
        {
            System.IO.FileInfo fi = new System.IO.FileInfo(fullPath);
            if (!fi.Directory.Exists)
            {
                fi.Directory.Create();
            }
            using (System.IO.FileStream fs = new System.IO.FileStream(fullPath, System.IO.FileMode.Create,
                System.IO.FileAccess.Write))
            using(System.IO.StreamWriter sw = new System.IO.StreamWriter(fs, System.Text.Encoding.UTF8))
            {
                for (int i = 0; i < dt.Rows.Count; i++) //写入各行数据
                {
                    var data = new List<string>();
                    for (int j = 0; j < dt.Columns.Count; j++)
                    {
                        var str = dt.Rows[i][j].ToString();
                        //替换英文冒号 英文冒号需要换成两个冒号
                        str = str.Replace("\"", "\"\"");
                        //含逗号 冒号 换行符的需要放到引号中
                        if (str.Contains(',') || str.Contains('"') || str.Contains('\r') || str.Contains('\n'))                        
                        {
                            str = $"\"{str}\"";
                        }
                        data.Add(str);                       
                    }                    
                    sw.WriteLine(string.Join(",",data));
                }
                sw.Close();
                fs.Close();
            }               
        }

        private static DataTable OpenCSVFile(string filepath)
        {
            string strpath = filepath; //csv文件的路径
            var table = new DataTable();
            table.Columns.Add("user");
            table.Columns.Add("menu");
            table.Columns.Add("folder");
            table.Columns.Add("time");

            if (!File.Exists(filepath))
            {
                return table;
            }

            string strline;
            string[] aryline;
            using (StreamReader mysr = new StreamReader(strpath, System.Text.Encoding.Default))
            {
                while ((strline = mysr.ReadLine()) != null)
                {
                    aryline = strline.Split(new char[] { ',' });
                    var row = table.NewRow();
                    for (int i = 0; i < table.Columns.Count; i++)
                    {
                        row[i] = aryline[i];
                    }
                    table.Rows.Add(row);
                }
                return table;
            }
        }
    }