C# CSV Generic T

This artice will write the main step to export generic data via csv with complete code and step by step.

1.Down load EntityFramework

Install-package entityframework -v 6.2.0

2.Add EF data model with only one table for simplicity.Take the AdventureWorks2017.Sales.SalesOrderDetail for example.

3.Override the ToString() method of the  newly added data model  cs file. 

public override string ToString()
{
string formatMsg = SalesOrderID + "," + SalesOrderDetailID + "," + CarrierTrackingNumber + "," +
OrderQty + "," + ProductID + "," + SpecialOfferID + "," + UnitPrice + "," + UnitPriceDiscount + "," +
LineTotal + "," + rowguid + "," + ModifiedDate + Environment.NewLine;
return formatMsg;
}

4.To be exact and precise,I will add StopWatch to log the cost in milliseconds.

The full code as below.

So far in my own pc, I can test as much as 3.8 million rows data and cost about 25 seconds as the screenshot illustrated.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Diagnostics;

namespace ConsoleApp322
{
class Program
{
static string cvsFileFullName = Directory.GetCurrentDirectory() + "\\" + DateTime.Now.ToString("yyyyMMddHHmmssffff") + ".csv";
static string fullLogFileName = Directory.GetCurrentDirectory() + "\\" + DateTime.Now.ToString("yyyyMMdd") + "log.txt";
static Stopwatch stopWatch = new Stopwatch();
static int exportNumber = 0;
static void Main(string[] args)
{
ExportTToCVS();
}

static void ExportTToCVS()
{
using (AdventureWorks2017Entities db = new AdventureWorks2017Entities())
{
List<SalesOrderDetail> orderList = db.SalesOrderDetails.ToList();
orderList.AddRange(orderList);
orderList.AddRange(orderList);
orderList.AddRange(orderList);
orderList.AddRange(orderList);
orderList.AddRange(orderList);
orderList.AddRange(orderList);
ExportListTToCVS<SalesOrderDetail>(orderList);
}
}

static void ExportListTToCVS<T>(List<T> dataList)
{

if(dataList!=null && dataList.Any())
{
stopWatch.Start();
exportNumber = dataList.Count;
StringBuilder orderBuilder = new StringBuilder();
var firstRowData = dataList.FirstOrDefault();
var orderProps = firstRowData.GetType().GetProperties().ToList();
orderBuilder.AppendLine(string.Join(",", orderProps.Select(x=>x.Name).ToArray()));
foreach(var dl in dataList)
{
orderBuilder.Append(dl.ToString());
}

using (StreamWriter streamWriter = new StreamWriter(cvsFileFullName))
{
streamWriter.WriteLine(orderBuilder.ToString());
}

stopWatch.Stop();
Process proc = Process.GetCurrentProcess();
long exportMemory = proc.PrivateMemorySize64;
string exportMsg = $"File path:{cvsFileFullName},export number:{exportNumber}," +
$"cost: {stopWatch.ElapsedMilliseconds} milliseconds,memory:{exportMemory}";
File.AppendAllText(fullLogFileName, exportMsg + Environment.NewLine);
}
}
}
}

标签：string,C#,orderList,System,ToString,Generic,static,using,CSV
来源： https://www.cnblogs.com/Fred1987/p/10344396.html