string fileName = "";
            string sourceFile = @"F:\Test文件夾\CSV";
            string bakFilePath = @"F:\Test文件夾\CSV\bak";

//匹配.csv的文件路徑地址集合
            string[] FullfillfilesList = Directory.GetFiles(sourceFile, "*.csv", 0);
            if (FullfillfilesList.Length > 0)
            {
                foreach (string Fullfillfiles in FullfillfilesList)
                {
                    //每一個文件名稱
                    fileName = Fullfillfiles.Substring(Fullfillfiles.LastIndexOf('\\') + 1);
                    //移動到Bak文件夾
                    ExecutionResult res = MoveFileToBak(sourceFile + "/" + fileName, bakFilePath, fileName);
                }
            }

public static ExecutionResult MoveFileToBak(string sourceFile, string bakFilePath, string bakFileName)
        {
            ExecutionResult result;
            FileInfo tempFileInfo;
            FileInfo tempBakFileInfo;
            DirectoryInfo tempDirectoryInfo;

            result = new ExecutionResult();
            tempFileInfo = new FileInfo(sourceFile);
            tempDirectoryInfo = new DirectoryInfo(bakFilePath);
            tempBakFileInfo = new FileInfo(bakFilePath + "\\" + bakFileName);
            try
            {
                if (!tempDirectoryInfo.Exists)
                    tempDirectoryInfo.Create();
                if (tempBakFileInfo.Exists)
                    tempBakFileInfo.Delete();
                //move file to bak
                tempFileInfo.MoveTo(bakFilePath + "\\" + bakFileName);

                result.Status = true;
                result.Message = "Move File To Bak OK";
                result.Anything = "SEND OK";
            }
            catch (Exception ex)
            {
                result.Status = false;
                result.Anything = "SEND Fail";
                result.Message = ex.Message;      
            }

            return result;
        }