C#读写日志文本文件

日志为文本文件
每列以制表符隔开 行以换行符隔开

本次示例简单实现如下相关功能：
1.正写日志文本 最新的日志放后面
2.倒写日志文本 最新的日志放前面
3.读日志文本内容显示在Label
4.读日志文本内容到DataTable 及 筛选后显示在GridView
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(以下操作并没有考虑相关如文件不存在等异常)

//1.正写日志 最新日志放最后面
protected void Button1_Click(object sender, EventArgs e)
{
    string strFilePath = Server.MapPath("log/log_200807_1.txt");
    System.IO.FileStream fs = new System.IO.FileStream(strFilePath, System.IO.FileMode.Append);
    System.IO.StreamWriter sw = new System.IO.StreamWriter(fs, System.Text.Encoding.Default);
    sw.WriteLine("'" + DateTime.Now.ToString() + "'/t'zhangsan'/t'Login.aspx'/t'登录A'");
    sw.Close();
    fs.Close();
}
//2.倒写日志 最新日志放最前面
protected void Button2_Click(object sender, EventArgs e)
{
    string strFilePath = Server.MapPath("log/log_200807_1.txt");
    string strOldText = File.ReadAllText(strFilePath, System.Text.Encoding.Default);
    File.WriteAllText(strFilePath, "'" + DateTime.Now.ToString() + "'/t'zhangsan'/t'Login.aspx'/t'登录B'/r/n", System.Text.Encoding.Default);
    File.AppendAllText(strFilePath, strOldText, System.Text.Encoding.Default);
}

//3.读日志文本到Label
protected void Button3_Click(object sender, EventArgs e)
{
    string strFilePath = Server.MapPath("log/log_200807_1.txt");
    FileStream fs = new FileStream(strFilePath, FileMode.Open, FileAccess.Read);
    StreamReader sr = new StreamReader(fs, System.Text.Encoding.Default);
    string strLine = sr.ReadLine();
    string str = "";
    while (strLine != null)
    {
        str += strLine.ToString() + "<br/>";
        strLine = sr.ReadLine();
    }
    sr.Close();
    fs.Close();
    this.Label1.Text = str;
}
//4.读日志文本内容到DataTable及筛选后显示在GridView
protected void Button4_Click(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.Add("日志时间");
    dt.Columns.Add("操作人员");
    dt.Columns.Add("日志页面");
    dt.Columns.Add("日志内容");
    
    string strFilePath = Server.MapPath("log/log_200807_1.txt");
    FileStream fs = new FileStream(strFilePath, FileMode.Open, FileAccess.Read);
    StreamReader sr = new StreamReader(fs, System.Text.Encoding.Default);
    string strLine = sr.ReadLine();
    
    while (strLine != null)
    {
        string[] strArray = new string[4];
        strArray = strLine.Split('/t');
        DataRow dr = dt.NewRow();
        dr[0] = strArray[0];
        dr[1] = strArray[1];
        dr[2] = strArray[2];
        dr[3] = strArray[3];
        dt.Rows.Add(dr);
        strLine = sr.ReadLine();
    }
    sr.Close();
    fs.Close();
    //筛选
    DataView dv = dt.DefaultView;
    dv.RowFilter = " 日志内容 Like '%A%' and 日志时间 >= '2008-7-8 14:12:50' ";
    //this.GridView1.DataSource = dt;
    this.GridView1.DataSource = dv;
    this.GridView1.DataBind();
}