修改后的MiniExcel源码

<div align="center"> <p><a href="https://www.nuget.org/packages/MiniExcel"><img src="https://img.shields.io/nuget/v/MiniExcel.svg" alt="NuGet"></a> <a href="https://www.nuget.org/packages/MiniExcel"><img src="https://img.shields.io/nuget/dt/MiniExcel.svg" alt=""></a> <a href="https://ci.appveyor.com/project/shps951023/miniexcel/branch/master"><img src="https://ci.appveyor.com/api/projects/status/b2vustrwsuqx45f4/branch/master?svg=true" alt="Build status"></a> <a href="https://gitee.com/dotnetchina/MiniExcel"><img src="https://gitee.com/dotnetchina/MiniExcel/badge/star.svg" alt="star"></a> <a href="https://github.com/shps951023/MiniExcel" rel="nofollow"><img src="https://img.shields.io/github/stars/shps951023/MiniExcel?logo=github" alt="GitHub stars"></a> <a href="https://www.nuget.org/packages/MiniExcel"><img src="https://img.shields.io/badge/.NET-%3E%3D%204.5-red.svg" alt="version"></a> </p> </div> --- <div align="center"> <p><strong><a href="README.md">English</a> | <a href="README.zh-CN.md">简体中文</a> | <a href="README.zh-Hant.md">繁體中文</a></strong></p> </div> --- <div align="center"> Your <a href="https://github.com/shps951023/MiniExcel">Star</a> and <a href="https://miniexcel.github.io">Donate</a> can make MiniExcel better </div> --- ### Introduction MiniExcel is simple and efficient to avoid OOM's .NET processing Excel tool. At present, most popular frameworks need to load all the data into the memory to facilitate operation, but it will cause memory consumption problems. MiniExcel tries to use algorithm from a stream to reduce the original 1000 MB occupation to a few MB to avoid OOM(out of memory).  ### Features - Low memory consumption, avoid OOM (out of memory) and full GC - Support `real-time` operation of each row of data - Support LINQ deferred execution, it can do low-consumption, fast paging and other complex queries - Lightweight, without Microsoft Office installed, no COM+, DLL size is less than 150KB - Easy API style to read/write/fill excel ### Get Started - [Import/Query Excel](#getstart1) - [Export/Create Excel](#getstart2) - [Excel Template](#getstart3) - [Excel Column Name/Index/Ignore Attribute](#getstart4) - [Examples](#getstart5) ### Installation You can install the package [from NuGet](https://www.nuget.org/packages/MiniExcel) ### Release Notes Please Check [Release Notes](docs) ### TODO Please Check [TODO](https://github.com/shps951023/MiniExcel/projects/1?fullscreen=true) ### Performance Benchmarks logic can be found in [MiniExcel.Benchmarks](benchmarks/MiniExcel.Benchmarks/Program.cs) , and test cli ```bash dotnet run -p .\benchmarks\MiniExcel.Benchmarks\ -c Release -f netcoreapp3.1 -- -f * --join ``` Output from the latest run is : ```bash BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19042 Intel Core i7-7700 CPU 3.60GHz (Kaby Lake), 1 CPU, 8 logical and 4 physical cores [Host] : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT Job-ZYYABG : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT IterationCount=3 LaunchCount=3 WarmupCount=3 ``` Benchmark History : [Link](https://github.com/shps951023/MiniExcel/issues/276) #### Import/Query Excel Logic : [**Test1,000,000x10.xlsx**](benchmarks/MiniExcel.Benchmarks/Test1%2C000%2C000x10.xlsx) as performance test basic file, 1,000,000 rows * 10 columns "HelloWorld" cells, 23 MB file size | Library | Method | Max Memory Usage | Mean | | ---------------------------- | -------------: | ---------------: | ---------------: | | MiniExcel | 'MiniExcel QueryFirst' | 0.109 MB | 0.0007264 sec | | ExcelDataReader | 'ExcelDataReader QueryFirst' | 15.24 MB | 10.66421 sec | | MiniExcel | 'MiniExcel Query' | 17.3 MB | 14.17933 sec | | ExcelDataReader | 'ExcelDataReader Query' | 17.3 MB | 22.56508 sec | | Epplus | 'Epplus QueryFirst' | 1,452 MB | 18.19801 sec | | Epplus | 'Epplus Query' | 1,451 MB | 23.64747 sec | | OpenXmlSDK | 'OpenXmlSDK Query' | 1,412 MB | 52.00327 sec | | OpenXmlSDK | 'OpenXmlSDK QueryFirst' | 1,413 MB | 52.34865 sec | | ClosedXml | 'ClosedXml QueryFirst' | 2,158 MB | 66.18897 sec | | ClosedXml | 'ClosedXml Query' | 2,184 MB | 191.43412 sec | #### Export/Create Excel Logic : create a total of 10,000,000 "HelloWorld" excel | Library | Method | Max Memory Usage | Mean | | ------------------------ | -------------: | ---------------: | -----------: | | MiniExcel | 'MiniExcel Create Xlsx' | 15 MB | 11.53181 sec | | Epplus | 'Epplus Create Xlsx' | 1,204 MB | 22.50971 sec | | OpenXmlSdk | 'OpenXmlSdk Create Xlsx' | 2,621 MB | 42.47399 sec | | ClosedXml | 'ClosedXml Create Xlsx' | 7,141 MB | 140.93992 sec | ### Excel Query/Import <a name="getstart1"></a> #### 1. Execute a query and map the results to a strongly typed IEnumerable [[Try it]](https://dotnetfiddle.net/w5WD1J) Recommand to use Stream.Query because of better efficiency. ```csharp public class UserAccount { public Guid ID { get; set; } public string Name { get; set; } public DateTime BoD { get; set; } public int Age { get; set; } public bool VIP { get; set; } public decimal Points { get; set; } } var rows = MiniExcel.Query<UserAccount>(path); // or using (var stream = File.OpenRead(path)) var rows = stream.Query<UserAccount>(); ```  #### 2. Execute a query and map it to a list of dynamic objects without using head [[Try it]](https://dotnetfiddle.net/w5WD1J) * dynamic key is `A.B.C.D..` | MiniExcel | 1 | | -------- | -------- | | Github | 2 | ```csharp var rows = MiniExcel.Query(path).ToList(); // or using (var stream = File.OpenRead(path)) { var rows = stream.Query().ToList(); Assert.Equal("MiniExcel", rows[0].A); Assert.Equal(1, rows[0].B); Assert.Equal("Github", rows[1].A); Assert.Equal(2, rows[1].B); } ``` #### 3. Execute a query with first header row [[Try it]](https://dotnetfiddle.net/w5WD1J) note : same column name use last right one Input Excel : | Column1 | Column2 | | -------- | -------- | | MiniExcel | 1 | | Github | 2 | ```csharp var rows = MiniExcel.Query(useHeaderRow:true).ToList(); // or using (var stream = File.OpenRead(path)) { var rows = stream.Query(useHeaderRow:true).ToList(); Assert.Equal("MiniExcel", rows[0].Column1); Assert.Equal(1, rows[0].Column2); Assert.Equal("Github", rows[1].Column1); Assert.Equal(2, rows[1].Column2); } ``` #### 4. Query Support LINQ Extension First/Take/Skip ...etc Query First ```csharp var row = MiniExcel.Query(path).First(); Assert.Equal("HelloWorld", row.A); // or using (var stream = File.OpenRead(path)) { var row = stream.Query().First(); Assert.Equal("HelloWorld", row.A); } ``` Performance between MiniExcel/ExcelDataReader/ClosedXML/EPPlus  #### 5. Query by sheet name ```csharp MiniExcel.Query(path, sheetName: "SheetName"); //or stream.Query(sheetName: "SheetName"); ``` #### 6. Query all sheet name and rows ```csharp var sheetNames = MiniExcel.GetSheetNames(path); foreach (var sheetName in sheetNames) { var rows = MiniExcel.Query(path, sheetName: sheetName); } ``` #### 7. Get Columns ```csharp var columns = MiniExcel.GetColumns(