Reading CSV or Tab delimited files from C#

Read data from a CSV files or Tab delimited file is very common especially in the era of big data where you get a large flat file exported, transformed and then reloaded. I am often shocked to see that people write their own algorithm for this when a very powerful module already exists and is free.

CSVhelper is available on GitHub and in its post basic usage you create a class file in your solution with the field name matching the fields in your Comma Separated file.  Then you simply do this:

• Create a class to store your data
  
     class myRecord { public string Id { get; set;} public string Name {get; set;} }

• Write code to open your file stream
• Reference the CsvHelper dll
• place a using statement for the CsvHelper at the top of your module
  
using CsvHelper;
• Use code similar to this where myFileStream is the stream you opened and myRecord is your class to fill with the data:
  
    using (var csv = new CsvReader(myFileStream))  {
       var recordList = csv.GetRecords().ToList();
   }

• Voila, the variable recordList is a list that contains an instance of myRecord per row in your file.

Now this will read a comma-separated file but what if your file is tab delimited.  Well that is just as simply create a configuration object and assign delimiter:

      CsvConfiguration config = new CsvConfiguration();
      config.Delimiter = "\t";

Now pass this configuration object into your call:

           using (var csv = new CsvReader(myFileStream, config))
          {
              var recordList = csv.GetRecords().ToList();
          }

This same library can be used to write to a CSV to Tab Delimited file. You would make a call something like this:

            // Write the file

            using (var swFlat = new StreamWriter(connectionString))

            {

                using (var csvwriteFlat = new CsvWriter(swFlat))

                {

                    if (recordList != null) csvwriteFlat.WriteRecords(recordList);

                }

            }