c# - 将数据库中的所有详细信息存储到一个文件中，然后下载该文件

Question

protected void btnDownload_Click(object sender, EventArgs e)
{
    SqlCommand Command = connection.CreateCommand();
                    SqlDataReader SQLRD;
                    Command.CommandText = "Select *from Attendance";
                   connection.Open();
        SQLRD = Command.ExecuteReader();            
        string data = "";
          while (SQLRD.Read())
        {
            data += SQLRD[0].ToString();
            data += SQLRD[1].ToString();

        }

        SQLRD.Close();
        connection.Close();

        string filename = @"C:\download.csv";
        FileStream fs = new FileStream(filename,FileMode.Append, FileAccess.Write);
        StreamWriter sw = new StreamWriter(fs);
        sw.WriteLine(data);
        sw.Flush();
        sw.Close();
        fs.Close();    }

这就是我目前所拥有的。我想将上述查询中的所有数据存储在一个文件中。将下载此文件。

Answer 1

protected void btnDownload_Click(object sender, EventArgs e)
{
   MySqlConnection connection = new MySqlConnection(@"Data Source=localhost\SQLEXPRESS;Initial Catalog=PSeminar;Integrated Security=true;Trusted_Connection=Yes;MultipleActiveResultSets=true");

   MySqlCommand myCommand = myConn.CreateCommand();
   MySqlDataReader SQLRD;
   myCommand.CommandText = "SELECT * FROM Attendance";
   connection.Open();
   SQLRD = myCommand.ExecuteReader();
   string data="";
   while (SQLRD.Read())
   {
     data += "Row data, arrange how you want";//SQLRD[0].Tostring();-->first coloum
   }
   SQLRD.Close();
   connection.Close();

   string filename = "F:\file1.txt";  //with path
   FileStream fs = new FileStream(filename, FileMode.Append, FileAccess.Write);
   StreamWriter sw = new StreamWriter(fs);
   sw.WriteLine(data);
   sw.Flush();
   sw.Close();
   fs.Close();
}

编辑代码:只需复制粘贴到您的代码中并更改文件名路径

            MySqlCommand Command = connection.CreateCommand();
            connection.Open();
            //SqlCommand Command = new SqlCommand();
            MySqlDataReader SQLRD;
            Command.CommandText = "Select * from Attendance";
            //connection.Open();
            SQLRD = Command.ExecuteReader();
            string data = "";
            while (SQLRD.Read())
            {
                data += SQLRD[0].ToString()+"\n";
                data += SQLRD[1].ToString()+"\n";

            }

            SQLRD.Close();
            connection.Close();

            string filename = @"F:\download.csv";
            FileStream fs = new FileStream(filename, FileMode.Append, FileAccess.Write);
            StreamWriter sw = new StreamWriter(fs);
            sw.WriteLine(data);
            sw.Flush();
            sw.Close();
            fs.Close();
        }