C#读取、写入CSV文件

Halcom · 发表于 2017-11-14 22:42:51

C#读取、写入CSV文件

读取CSV文件到DataTable，方便插入到界面datagridview中：

public static DataTable OpenCSV(string filePath)//从csv读取数据返回table
{
System.Text.Encoding encoding = GetType(filePath); //Encoding.ASCII;//
DataTable dt = new DataTable();
System.IO.FileStream fs = new System.IO.FileStream(filePath, System.IO.FileMode.Open,
System.IO.FileAccess.Read);
System.IO.StreamReader sr = new System.IO.StreamReader(fs, encoding);
//记录每次读取的一行记录
string strLine = "";
//记录每行记录中的各字段内容
string[] aryLine = null;
string[] tableHead = null;
//标示列数
int columnCount = 0;
//标示是否是读取的第一行
bool IsFirst = true;
//逐行读取CSV中的数据
while ((strLine = sr.ReadLine()) != null)
{
if (IsFirst == true)
{
tableHead = strLine.Split(',');
IsFirst = false;
columnCount = tableHead.Length;
//创建列
for (int i = 0; i < columnCount; i++)
{
DataColumn dc = new DataColumn(tableHead[i]);
dt.Columns.Add(dc);
}
}
else
{
aryLine = strLine.Split(',');
DataRow dr = dt.NewRow();
for (int j = 0; j < columnCount; j++)
{
dr[j] = aryLine[j];
}
dt.Rows.Add(dr);
}
}
if (aryLine != null && aryLine.Length > 0)
{
dt.DefaultView.Sort = tableHead[0] + " " + "asc";
}
sr.Close();
fs.Close();
return dt;
}
/// 给定文件的路径，读取文件的二进制数据，判断文件的编码类型
/// <param name="FILE_NAME">文件路径</param>
/// <returns>文件的编码类型</returns>
public static System.Text.Encoding GetType(string FILE_NAME)
{
System.IO.FileStream fs = new System.IO.FileStream(FILE_NAME, System.IO.FileMode.Open,
System.IO.FileAccess.Read);
System.Text.Encoding r = GetType(fs);
fs.Close();
return r;
}
/// 通过给定的文件流，判断文件的编码类型
/// <param name="fs">文件流</param>
/// <returns>文件的编码类型</returns>
public static System.Text.Encoding GetType(System.IO.FileStream fs)
{
byte[] Unicode = new byte[] { 0xFF, 0xFE, 0x41 };
byte[] UnicodeBIG = new byte[] { 0xFE, 0xFF, 0x00 };
byte[] UTF8 = new byte[] { 0xEF, 0xBB, 0xBF }; //带BOM
System.Text.Encoding reVal = System.Text.Encoding.Default;
System.IO.BinaryReader r = new System.IO.BinaryReader(fs, System.Text.Encoding.Default);
int i;
int.TryParse(fs.Length.ToString(), out i);
byte[] ss = r.ReadBytes(i);
if (IsUTF8Bytes(ss) || (ss[0] == 0xEF && ss[1] == 0xBB && ss[2] == 0xBF))
{
reVal = System.Text.Encoding.UTF8;
}
else if (ss[0] == 0xFE && ss[1] == 0xFF && ss[2] == 0x00)
{
reVal = System.Text.Encoding.BigEndianUnicode;
}
else if (ss[0] == 0xFF && ss[1] == 0xFE && ss[2] == 0x41)
{
reVal = System.Text.Encoding.Unicode;
}
r.Close();
return reVal;
}
/// 判断是否是不带 BOM 的 UTF8 格式
/// <param name="data"></param>
/// <returns></returns>
private static bool IsUTF8Bytes(byte[] data)
{
int charByteCounter = 1;　 //计算当前正分析的字符应还有的字节数
byte curByte; //当前分析的字节.
for (int i = 0; i < data.Length; i++)
{
curByte = data[i];
if (charByteCounter == 1)
{
if (curByte >= 0x80)
{
//判断当前
while (((curByte <<= 1) & 0x80) != 0)
{
charByteCounter++;
}
//标记位首位若为非0 则至少以2个1开始如:110XXXXX...........1111110X　
if (charByteCounter == 1 || charByteCounter > 6)
{
return false;
}
}
}
else
{
//若是UTF-8 此时第一位必须为1
if ((curByte & 0xC0) != 0x80)
{
return false;
}
charByteCounter--;
}
}
if (charByteCounter > 1)
{
throw new Exception("非预期的byte格式");
}
return true;
}

复制代码

在此特别注意输入的路径是string类型；注意：如果是其它软件转换的变量.tostring()也会有格式差异的。

参考：
【1】http://blog.csdn.net/xgf415/article/details/51366877

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