//调用方法
public class FileObject
public static Encoding GetFileEncoding(string fileName)
{
Encoding encode = Encoding.Default;
Common.IdentifyEncoding sinodetector;
sinodetector = new Common.IdentifyEncoding();
FileInfo finfo = new FileInfo(fileName);
encode = sinodetector.GetEncoding(sinodetector.GetEncodingName(finfo));
return encode;
}
Encoding curEncode = Common.FileObject.GetFileEncoding(bomFile.FileLocation);
CsvReader csvReader = new CsvReader(backupFile, curEncode);
DataTable dt = csvReader.ReadIntoDataTable();
//CSV Reader代码
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Text;
namespace Common
{
/// <summary>
/// Class to read csv content from various sources
/// </summary>
public sealed class CsvReader : IDisposable
{
#region Members
private FileStream _fileStream;
private Stream _stream;
private StreamReader _streamReader;
private StreamWriter _streamWriter;
private Stream _memoryStream;
private Encoding _encoding;
private readonly StringBuilder _columnBuilder = new StringBuilder(100);
private readonly Type _type = Type.File;
#endregion Members
#region Properties
/// <summary>
/// Gets or sets whether column values should be trimmed
/// </summary>
private bool _TrimColumns;
public bool TrimColumns
{
get { return _TrimColumns; }
set { _TrimColumns = value; }
}
/// <summary>
/// Gets or sets whether the csv file has a header row
/// </summary>
private bool _HasHeaderRow;
public bool HasHeaderRow
{
get { return _HasHeaderRow; }
set { _HasHeaderRow = value; }
}
/// <summary>
/// Returns a collection of fields or null if no record has been read
/// </summary>
private List<string> _Fields;
public List<string> Fields
{
get { return _Fields; }
set { _Fields = value; }
}
/// <summary>
/// Gets the field count or returns null if no fields have been read
/// </summary>
public int? FieldCount
{
get
{
return (Fields != null ? Fields.Count : (int?)null);
}
}
#endregion Properties
#region Enums
/// <summary>
/// Type enum
/// </summary>
private enum Type
{
File,
Stream,
String
}
#endregion Enums
#region Constructors
/// <summary>
/// Initialises the reader to work from a file
/// </summary>
/// <param name="filePath">File path</param>
public CsvReader(string filePath)
{
_type = Type.File;
Initialise(filePath, Encoding.Default);
}
/// <summary>
/// Initialises the reader to work from a file
/// </summary>
/// <param name="filePath">File path</param>
/// <param name="encoding">Encoding</param>
public CsvReader(string filePath, Encoding encoding)
{
_type = Type.File;
Initialise(filePath, encoding);
}
/// <summary>
/// Initialises the reader to work from an existing stream
/// </summary>
/// <param name="stream">Stream</param>
public CsvReader(Stream stream)
{
_type = Type.Stream;
Initialise(stream, Encoding.Default);
}
/// <summary>
/// Initialises the reader to work from an existing stream
/// </summary>
/// <param name="stream">Stream</param>
/// <param name="encoding">Encoding</param>
public CsvReader(Stream stream, Encoding encoding)
{
_type = Type.Stream;
Initialise(stream, encoding);
}
/// <summary>
/// Initialises the reader to work from a csv string
/// </summary>
/// <param name="encoding"></param>
/// <param name="csvContent"></param>
public CsvReader(Encoding encoding, string csvContent)
{
_type = Type.String;
Initialise(encoding, csvContent);
}
#endregion Constructors
#region Methods
/// <summary>
/// Initialises the class to use a file
/// </summary>
/// <param name="filePath"></param>
/// <param name="encoding"></param>
private void Initialise(string filePath, Encoding encoding)
{
if (!File.Exists(filePath))
throw new FileNotFoundException(string.Format("The file '{0}' does not exist.", filePath));
_fileStream = File.OpenRead(filePath);
Initialise(_fileStream, encoding);
}
/// <summary>
/// Initialises the class to use a stream
/// </summary>
/// <param name="stream"></param>
/// <param name="encoding"></param>
private void Initialise(Stream stream, Encoding encoding)
{
if (stream == null)
throw new ArgumentNullException("The supplied stream is null.");
_stream = stream;
_stream.Position = 0;
_encoding = (encoding ?? Encoding.Default);
_streamReader = new StreamReader(_stream, _encoding);
}
/// <summary>
/// Initialies the class to use a string
/// </summary>
/// <param name="encoding"></param>
/// <param name="csvContent"></param>
private void Initialise(Encoding encoding, string csvContent)
{
if (csvContent == null)
throw new ArgumentNullException("The supplied csvContent is null.");
_encoding = (encoding ?? Encoding.Default);
_memoryStream = new MemoryStream(csvContent.Length);
_streamWriter = new StreamWriter(_memoryStream);
_streamWriter.Write(csvContent);
_streamWriter.Flush();
Initialise(_memoryStream, encoding);
}
/// <summary>
/// Reads the next record
/// </summary>
/// <returns>True if a record was successfuly read, otherwise false</returns>
public bool ReadNextRecord()
{
Fields = null;
string line = _streamReader.ReadLine();
if (line == null)
return false;
ParseLine(line);
return true;
}
/// <summary>
/// Reads a csv file format into a data table. This method
/// will always assume that the table has a header row as this will be used
/// to determine the columns.
/// </summary>
/// <returns></returns>
public DataTable ReadIntoDataTable()
{
return ReadIntoDataTable(new System.Type[] {});
}
/// <summary>
/// Reads a csv file format into a data table. This method
/// will always assume that the table has a header row as this will be used
/// to determine the columns.
/// </summary>
/// <param name="columnTypes">Array of column types</param>
/// <returns></returns>
public DataTable ReadIntoDataTable(System.Type[] columnTypes)
{
DataTable dataTable = new DataTable();
bool addedHeader = false;
_stream.Position = 0;
while (ReadNextRecord())
{
if (!addedHeader)
{
for (int i = 0; i < Fields.Count; i++)
dataTable.Columns.Add(Fields[i], (columnTypes.Length > 0 ? columnTypes[i] : typeof(string)));
addedHeader = true;
continue;
}
DataRow row = dataTable.NewRow();
for (int i = 0; i < Fields.Count; i++)
row[i] = Fields[i];
dataTable.Rows.Add(row);
}
return dataTable;
}
/// <summary>
/// Parses a csv line
/// </summary>
/// <param name="line">Line</param>
private void ParseLine(string line)
{
Fields = new List<string>();
bool inColumn = false;
bool inQuotes = false;
_columnBuilder.Remove(0, _columnBuilder.Length);
// Iterate through every character in the line
for (int i = 0; i < line.Length; i++)
{
char character = line[i];
// If we are not currently inside a column
if (!inColumn)
{
// If the current character is a double quote then the column value is contained within
// double quotes, otherwise append the next character
/*
if (character == '"')
inQuotes = true;
else
_columnBuilder.Append(character);
inColumn = true;
continue;
* */
if (character == '"')
{
inQuotes = true;
inColumn = true;
continue;
}
else if (character == ',' && (0 < (i - 1) && line[i - 1] == ','))
{
inColumn = false;
}
else
{
_columnBuilder.Append(character);
inColumn = true;
continue;
}
}
// If we are in between double quotes
if (inQuotes)
{
// If the current character is a double quote and the next character is a comma or we are at the end of the line
// we are now no longer within the column.
// Otherwise increment the loop counter as we are looking at an escaped double quote e.g. "" within a column
if (character == '"' && ((line.Length > (i + 1) && line[i + 1] == ',') || ((i + 1) == line.Length)))
{
inQuotes = false;
inColumn = false;
i++;
}
else if (character == '"' && line.Length > (i + 1) && line[i + 1] == '"')
i++;
}
else if (character == ',')
inColumn = false;
// If we are no longer in the column clear the builder and add the columns to the list
if (!inColumn)
{
Fields.Add(TrimColumns ? _columnBuilder.ToString().Trim() : _columnBuilder.ToString());
_columnBuilder.Remove(0, _columnBuilder.Length);
}
else // append the current column
_columnBuilder.Append(character);
}
// If we are still inside a column add a new one
if (inColumn)
Fields.Add(TrimColumns ? _columnBuilder.ToString().Trim() : _columnBuilder.ToString());
}
/// <summary>
/// Disposes of all unmanaged resources
/// </summary>
public void Dispose()
{
if (_streamReader != null)
{
_streamReader.Close();
_streamReader.Dispose();
}
if (_streamWriter != null)
{
_streamWriter.Close();
_streamWriter.Dispose();
}
if (_memoryStream != null)
{
_memoryStream.Close();
_memoryStream.Dispose();
}
if (_fileStream != null)
{
_fileStream.Close();
_fileStream.Dispose();
}
if ((_type == Type.String || _type == Type.File) && _stream != null)
{
_stream.Close();
_stream.Dispose();
}
}
#endregion Methods
}
}
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