LibCSV4Net

Library for reading and writing tabular (CSV) files.

NuGet package

Goal

The goal is to have library, which does not depend on third party components is fast and simple to use.

History

This library started its life as port of Python CSV module. At the time I was searching for .Net library which could handle third party legacy CSV format. I didn't succeeded, so I created this library. It was tested with some huge data imports/exports.

API

CSVReader class is responsible for reading and parsing tabular data. (CSVReader example)
CSVWriter class is responsible for writing tabular data to stream. (CSVWriter example)
CSVAdapter class is advanced csv reader/writer that supports read/write of all records and transformations. (CSVAdapter example)
Dialect class defines rules for CSV parsing and generation options.

CSVReader class

CSVReader class is responsible for reading and parsing tabular data. Parsing is controlled by set of rules defined in Dialect. Exposes the following operations:

Next() - reads and parses next record (returns true on success)
Current - return current record as array of strings
Headers - return headers as array of strings

CSVWriter class

CSVWriter class is responsible for writing tabular data to stream.

CSVAdapter class

CSVAdapter class is advanced csv reader/writer that supports read/write of all records and transformations.

Dialect class

Dialect class defines rules for CSV parsing and generation options.

Example

CSVAdapter example

// Define your custom Data transfer object
public class Dto
{
	public string Title { get; set; }
	public DateTime CreatedOn { get; set; }
	public decimal Total { get; set; }
	public string Description { get; set; }
}

// Define dialect
var dialect = new Dialect
{
	DoubleQuote = true,
	Delimiter = ';',
	Quote = '"',
	Escape = '\0',
	SkipInitialSpace = false,
	LineTerminator = "\r\n",
	Quoting = QuoteStyle.QuoteMinimal,
	Strict = false,
	HasHeader = false
};

// Define transformer from your custom type to tabular data.
public class ExportTransformer : IDataTransformer
{
	public object TransformTuple(object[] tuple, string[] aliases)
	{
		throw new System.NotImplementedException();
	}

	public IEnumerable TransformResult(IEnumerable result)
	{
		throw new System.NotImplementedException();
	}

	public object[] TransformRow(object tuple)
	{
		var data = tuple as Dto;
		if (data == null)
		{
			throw new CsvException("Row is empty!");
		}

		var row = new string[4];
		row[0] = data.Title;
		row[1] = data.CreatedOn.ToString(CultureInfo.InvariantCulture);
		row[2] = data.Total.ToString(CultureInfo.InvariantCulture);
		row[3] = data.Description;
		return row;
	}
}

// Now we will write all data to csv file.
var data = new[]
{
	new Dto { Title = "Title1", CreatedOn = DateTime.Now, Total = 1000.00M, Description = "Description1" },
	new Dto { Title = "Title2", CreatedOn = DateTime.Now, Total = 2000.00M, Description = "Description2" },
};

var headers = new[] { "Tile", "CreatedOn", "Total", "Description" };
using (var writer = new StreamWriter(@"C:\test.csv"))
{
	using (var adapter = new CSVAdapter(dialect, writer, headers))
	{
		adapter.WriteAll(data, new ExportTransformer());
	}
}

CSVReader example

string input = "Header#1;Header#2;Header#3\r\n1;2;3\r\n4;5;6";

var dialect = new Dialect
{
	DoubleQuote = true,
	Delimiter = ';',
	Quote = '\'',
	Escape = '\\',
	SkipInitialSpace = true,
	LineTerminator = "\r\n",
	Quoting = QuoteStyle.QuoteNone,
	Strict = true,
	HasHeader = true
};

using (var reader = new CSVReader(dialect, new StringReader(input)))
{
	reader.Open();

	foreach (var item in reader.Headers)
	{
		Console.Write(item + "| ");
	}
	Console.WriteLine();

	while (reader.Next())
	{
		var record = reader.Current;
		if (record != null && record.Length > 0)
		{
			foreach (var item in record)
			{
				Console.Write(item + "| ");
			}
			Console.WriteLine();
		}
	}
}

CSVWriter example

var dialect = new Dialect
{
	DoubleQuote = true,
	Delimiter = ';',
	Quote = '\'',
	Escape = '\\',
	SkipInitialSpace = true,
	LineTerminator = "\r\n",
	Quoting = QuoteStyle.QuoteNone,
	Strict = true,
	HasHeader = false
};

object[] data = new[]
{
	new object[] { 123, 123.45, 10M, "This is string", new DateTime(2010, 9, 3, 0, 0, 0), null },
	new object[] { 456, 456.78, 11M, "This is string too", new DateTime(2012, 04, 04, 0, 0, 0), null }
};

using (var memoryStream = new MemoryStream())
{
	using (TextWriter textWriter = new StreamWriter(memoryStream))
	{
		using (CSVWriter writer = new CSVWriter(dialect, textWriter))
		{
			foreach (object[] row in data)
			{
				writer.WriteRow(row);
			}
		}
	}

	Encoding encoding = Encoding.ASCII;
	Console.Write(encoding.GetString(memoryStream.ToArray()));
}

Changes

See CHANGES.md for details.

License

This is free software, and you are welcome to redistribute it under certain conditions; see LICENSE.txt for details.

Author contact

Darius Kucinskas d.kucinskas@gmail.com, http://blog-of-darius.blogspot.com/

Accpeted one or more pull request from

ssharunas ssharunas[at]yahoo[dot]co[dot]uk
emmorts (Tomas Stropus) stropust[at]gmail[dot]com
gedbac (Gediminas Backevicius) gediminas.backevicius[at]gmail[dot]com

gedbac/LibCSV4Net