Question

环境 - Windows 10，Visual Studio 2017，netcore2.0，Debug build。

在调试时使用Epplus 4.1.1保存Excel文件时，保存操作所需的时间比我预期的要长很多。

这是使用Debug运行时的一些时间 - ＆gt;开始调试

Saving 100 rows in 2065ms.
Saving 200 rows in 2050ms.
Saving 400 rows in 4003ms.
Saving 800 rows in 11360ms.
Saving 1600 rows in 18377ms.
Saving 3200 rows in 34139ms.

使用Debug运行时相同 - ＆gt;无需调试即可启动

Saving 100 rows in 401ms.
Saving 200 rows in 49ms.
Saving 400 rows in 28ms.
Saving 800 rows in 58ms.
Saving 1600 rows in 94ms.
Saving 3200 rows in 198ms.

在针对.NET Framework 4.6.1时，调试时的结果要好得多 -

Saving 100 rows in 215ms.
Saving 200 rows in 26ms.
Saving 400 rows in 42ms.
Saving 800 rows in 78ms.
Saving 1600 rows in 146ms.
Saving 3200 rows in 279ms.

我显然知道调试是糖蜜慢，但这是一个微不足道的数据量。在针对.NET Core 2.0进行调试时，有什么方法可以帮助您加快速度吗？

-

以下是产生上述输出的程序 -

namespace ConsoleApp9
{
    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Text;
    using System.Linq;
    using System.Diagnostics;

    using OfficeOpenXml;

    public class Foo
    {
        public string Name { get; set; }
        public int Number { get; set; }
        public char? Character { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);

            IEnumerable<Foo> RandomFoo()
            {
                var random = new Random();
                const string chars = "ABCDEFGHIJKLH";
                while (true)
                {
                    yield return new Foo
                    {
                        Character = random.NextDouble() < .1 ? null : (char?) 'A',
                        Number = random.Next(0, 10),
                        Name = new string(Enumerable.Repeat(chars, 8)
                            .Select(x => x[random.Next(x.Length)])
                            .ToArray()
                        )
                    };
                }
            }

            for (var i = 100; i <= 1000000; i *= 2)
            {
                var sw = Stopwatch.StartNew();

                var stream = new MemoryStream();
                using (var package = new ExcelPackage(stream))
                {
                    var sheet = package.Workbook.Worksheets.Add("Sheet");
                    var foos = RandomFoo().Take(i);
                    sheet.Cells["A1"].LoadFromCollection(foos);

                    package.Save(); // very long operation here
                    stream.Seek(0, SeekOrigin.Begin);
                }

                var file = new FileInfo("test.xlsx");
                using (var fileStream = file.Create())
                {
                    stream.CopyTo(fileStream);
                }

                Console.WriteLine($"Saving {i} rows in {sw.ElapsedMilliseconds}ms.");
            }
        }
    }
}

Answer 1

EPPLUS v4.4.1并不完全兼容.net core 2，但我的数字不同于你的（逻辑的）。

Saving 100 rows in 360ms.
Saving 200 rows in 23ms.
Saving 400 rows in 48ms.
Saving 800 rows in 84ms.
Saving 1600 rows in 183ms.
Saving 3200 rows in 317ms.
Saving 6400 rows in 592ms.
Saving 12800 rows in 1157ms.
Saving 25600 rows in 2352ms.
Saving 51200 rows in 4848ms.
Saving 102400 rows in 9613ms.
Saving 204800 rows in 18917ms.

我建议你使用.net core 2兼容的预发行版环境

以下是我在Windows 10，Visual Studio 2017，netcore2.0，Debug build中使用EPPLUS v4.5.0.1-beta获得的数字。

Saving 100 rows in 585ms.
Saving 200 rows in 114ms.
Saving 400 rows in 125ms.
Saving 800 rows in 159ms.
Saving 1600 rows in 233ms.
Saving 3200 rows in 360ms.
Saving 6400 rows in 655ms.
Saving 12800 rows in 1251ms.
Saving 25600 rows in 2422ms.
Saving 51200 rows in 4840ms.
Saving 102400 rows in 9789ms.
Saving 204800 rows in 19094ms.
Saving 409600 rows in 38093ms.

Answer 2

I had the same issue, it was because I stored character values in cells : worksheet.Cells[i,j].Value = 'A'; It is working BUT when saving it produces a conversion cast exception that slows a lot the VS debugger. Just store a string! worksheet.Cells[i,j].Value = "A";

调试时Epplus Save（），SaveAs（）等方法运行速度非常慢

2 个答案: