C# 读写文件

介绍一下C#的文件操作方法。

1. TXT文件

写入

//using会自动关闭StreamWriter
using (StreamWriter sw = new StreamWriter("TestFile.txt")) 
{
    sw.Write("This is the ");
    sw.WriteLine("header for the file.");
    sw.WriteLine("-------------------");

    sw.Write("The date is: ");
    sw.WriteLine(DateTime.Now);
}

2. CSV文件

写入

与txt的写出方法一样，唯一的区别是txt列之间是用"\t"分割，csv用"," 。

using (StreamWriter sw = new StreamWriter(filePath, false, Encoding.Default))
{
    string repStr = ",";
    string colHead = string.Empty;

    for (int i = 1; i < dataTable.Columns.Count-2; i++)
    {
        colHead += dataTable.Columns[i].ColumnName + repStr;
    }

    if (colHead.Contains(repStr))
    {
        colHead = colHead.Remove(colHead.LastIndexOf(repStr));
    }
    sw.WriteLine(colHead);

    for (int i = 0; i < dataTable.Rows.Count; i++)
    {
        int cell = dataTable.Rows[i].ItemArray.Count()-2;
        string content = string.Empty;

        for (int j = 1; j < cell; j++)
        {
            content += dataTable.Rows[i][j] + repStr;
        }

        if (content.Contains(repStr))
        {
            content = content.Remove(content.LastIndexOf(repStr));
        }
        sw.WriteLine(content);

    }

}