By default, the data is transferred in binary mode without any processing. However, when transferring text data between platforms which use different end-of-line sequences (Windows use <CR><LF>, Unix uses <LF>), it's essential to have the sequences automatically converted by setting the transfer mode to ASCII.
In a multi-file transfer, to determine whether a file should be transferred in ASCII or Binary mode, Ultimate FTP uses the AsciiFileSearchConditions property to check against the processing file. If a file matches that criteria, the file will be transferred in ASCII mode; otherwise, binary mode is used.
client.AsciiFileSearchConditions = new SearchCondition[] { new NameSearchCondition("*.txt") }; // Upload TXT files. // TXT will be transferred in ASCII mode, all other files will be transferred in Binary mode client.Upload(@"c:\data\*.txt", "/data");