C#使用MiniExcel导入导出数据到Excel/CSV文件【IO操作】

MiniExcel简介

简单、高效避免OOM的.NET处理Excel查、写、填充数据工具。
目前主流框架大多需要将数据全载入到内存方便操作，但这会导致内存消耗问题，MiniExcel 尝试以 Stream 角度写底层算法逻辑，能让原本1000多MB占用降低到几MB，避免内存不够情况。

 特点：

    低内存耗用，避免OOM、频繁 Full GC 情况
    支持即时操作每行数据
    兼具搭配 LINQ 延迟查询特性，能办到低消耗、快速分页等复杂查询
    轻量，不需要安装 Microsoft Office、COM+，DLL小于150KB
    简便操作的 API 风格

项目地址：mini-software/MiniExcel: Fast, Low-Memory, Easy Excel .NET helper to import/export/template spreadsheet (support Linux, Mac) (github.com)

安装 MiniExcel

Nuget

 导出数据

 public class Student
  {
      public string? Name { get; set; }
      public string? Home { get; set; }
      public int? Age {  get; set; }   
  }

 //获得当前目录的路径
 string currentDirectory = Directory.GetCurrentDirectory();

 //合并当前目录与Excel文件名
 var path = Path.Combine(currentDirectory, $"{Guid.NewGuid()}.xlsx");
 
  List<Student> studentList = new List<Student>()
  {
      new Student { Name = "小东", Home = "New York", Age = 25 },
      new Student { Name = "小西", Home = "London", Age = 22 },
      new Student { Name = "小南", Home = "Paris", Age = 28 },
      new Student { Name = "小北", Home = "Tokyo", Age = 24 },
      new Student { Name = "小王", Home = "Berlin", Age = 26 }
 };

MiniExcel.SaveAs(path, studentList);

        /// <summary>
        /// 操作3
        /// 导出数据
        /// 导出指定库全部数据,或导出指定库用户选中的数据
        /// </summary>
        /// <returns></returns>
        [RelayCommand(CanExecute = nameof(CanExport))]
        private async Task ExportAsync()
        {
            SaveFileDialog saveFileDialog = new SaveFileDialog();
            //打开的文件选择对话框上的标题
            saveFileDialog.Title = "请选择文件夹";
            //设置文件类型
            saveFileDialog.Filter = "文本文件(*.xlsx)|*.xlsx";
            saveFileDialog.FileName = @$"{CurrentQALibrary.QALibraryName}{DateTime.Now:M}.xlsx";
            //设置默认文件类型显示顺序
            saveFileDialog.FilterIndex = 1;
            //保存对话框是否记忆上次打开的目录
            saveFileDialog.RestoreDirectory = true;

            //按下确定选择的按钮
            if (saveFileDialog.ShowDialog() == true)
            {
                //获得文件路径
                string localFilePath = saveFileDialog.FileName.ToString();
                if (QAModels.Where(e => e.IsChecked).Count() == 0)

                {
                    if (File.Exists(localFilePath)) File.Delete(localFilePath);
                    var qaModels = from qa in QAModels where qa.IsChecked == true && qa.QALibraryID == CurrentQALibrary.QALibraryID select new { 题型 = qa.Questiontype, 试卷内容 = qa.Content, 题目 = qa.SubjectTitle };

                    await MiniExcel.SaveAsAsync(localFilePath, qaModels);
                }
                else
                {
                    if (File.Exists(localFilePath)) File.Delete(localFilePath);
                    var qaModels = from qa in QAModels where qa.IsChecked == true && qa.QALibraryID == CurrentQALibrary.QALibraryID select new { 题型 = qa.Questiontype, 试卷内容=qa.Content,题目=qa.SubjectTitle };
                    await MiniExcel.SaveAsAsync(localFilePath, qaModels);
                }

            }

        }

导入数据

 var path = "你的文件路径";
 var rows = MiniExcel.Query<Student>(path);