using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
namespace ReadWriteCsv
{
/// <summary>
/// Class to store one CSV row
/// </summary>
public class CsvRow : List<string>
{
public string LineText { get; set; }
}
/// <summary>
/// Class to write data to a CSV file
/// </summary>
public class CsvFileWriter : StreamWriter
{
public CsvFileWriter(Stream stream)
: base(stream)
{
}
public CsvFileWriter(string filename)
: base(filename)
{
}
/// <summary>
/// Writes a single row to a CSV file.
/// </summary>
/// <param name="row">The row to be written</param>
public void WriteRow(CsvRow row)
{
StringBuilder builder = new StringBuilder();
bool firstColumn = true;
foreach (string value in row)
{
// Add separator if this isn't the first value
if (!firstColumn)
builder.Append(',');
// Implement special handling for values that contain comma or quote
// Enclose in quotes and double up any double quotes
if (value.IndexOfAny(new char[] { '"', ',' }) != -1)
builder.AppendFormat(""{0}"", value.Replace(""", """"));
else
builder.Append(value);
firstColumn = false;
}
row.LineText = builder.ToString();
WriteLine(row.LineText);
}
}
/// <summary>
/// Class to read data from a CSV file
/// </summary>
public class CsvFileReader : StreamReader
{
public CsvFileReader(Stream stream)
: base(stream)
{
}
public CsvFileReader(string filename)
: base(filename)
{
}
/// <summary>
/// Reads a row of data from a CSV file
/// </summary>
/// <param name="row"></param>
/// <returns></returns>
public bool ReadRow(CsvRow row)
{
row.LineText = ReadLine();
if (String.IsNullOrEmpty(row.LineText))
return false;
int pos = 0;
int rows = 0;
while (pos < row.LineText.Length)
{
string value;
// Special handling for quoted field
if (row.LineText[pos] == '"')
{
// Skip initial quote
pos++;
// Parse quoted value
int start = pos;
while (pos < row.LineText.Length)
{
// Test for quote character
if (row.LineText[pos] == '"')
{
// Found one
pos++;
// If two quotes together, keep one
// Otherwise, indicates end of value
if (pos >= row.LineText.Length || row.LineText[pos] != '"')
{
pos--;
break;
}
}
pos++;
}
value = row.LineText.Substring(start, pos - start);
value = value.Replace("""", """);
}
else
{
// Parse unquoted value
int start = pos;
while (pos < row.LineText.Length && row.LineText[pos] != ',')
pos++;
value = row.LineText.Substring(start, pos - start);
}
// Add field to list
if (rows < row.Count)
row[rows] = value;
else
row.Add(value);
rows++;
// Eat up to and including next comma
while (pos < row.LineText.Length && row.LineText[pos] != ',')
pos++;
if (pos < row.LineText.Length)
pos++;
}
// Delete any unused items
while (row.Count > rows)
row.RemoveAt(rows);
// Return true if any columns read
return (row.Count > 0);
}
}
}