几个Excel文件合并去重分类

需要使用EPPlus操作Excel

安装EPPlus如下所示：
EPPlus.Core

```java
using OfficeOpenXml;
using System.Collections;
using System.Collections.Generic;

namespace Excel数据处理
{
    public partial class Form1 : Form
    {
        string filePath;
        string selectedFolderPath;
        static int n = 0;
        List<WaterData> waterList = new List<WaterData>();
        List<WaterData> distinctList = new List<WaterData>();
        List<List<WaterData>> list = new List<List<WaterData>>();
        public class WaterData
        {
            public int Id { get; set; }
            public string? Name { get; set; }
            public string? WaterLevel { get; set; }
            public string? WaterChange { get; set; }
            public string? Source { get; set; }
        }

public Form1()
        {
            InitializeComponent();
        }

private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.Filter = "Excel Files (*.xlsx; *.xls;*.csv)|*.xlsx; *.xls;*.csv";
            openFileDialog.FilterIndex = 1;
            openFileDialog.Multiselect = false;

if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                filePath = openFileDialog.FileName;
                richTextBox1.Text += $"您选中的文件路径为：{filePath}\r\n";
                richTextBox1.Text += $"正在导入Excel数据...\r\n";
                ExcelPackage.LicenseContext = OfficeOpenXml.LicenseContext.NonCommercial;
                using (ExcelPackage package = new ExcelPackage(filePath))
                {

ExcelWorksheet worksheet = package.Workbook.Worksheets[0];

//获取表格的列数和行数
                    int rowCount = worksheet.Dimension.Rows;
                    int colCount = worksheet.Dimension.Columns;

for (int i = 0; i < rowCount - 1; i++)
                    {
                        //创建一个realData类保存数据
                        var data = new WaterData();
                        data.Id = n;
                        data.Name = (string)worksheet.Cells[i + 2, 3].Value;
                        data.WaterLevel = Convert.ToString(worksheet.Cells[i + 2, 4].Value);
                        data.WaterChange = Convert.ToString(worksheet.Cells[i + 2, 5].Value);
                        data.Source = (string)worksheet.Cells[i + 2, 2].Value;
                        waterList.Add(data);
                        n++;
                    }
                    richTextBox1.Text += $"导入Excel数据成功，数据量为：{rowCount - 1}\r\n";
                    package.Save();
                }
            }
            else
            {
                MessageBox.Show("您本次没有选择任何文件！！！");
            }
        }

private void button2_Click(object sender, EventArgs e)
        {
            richTextBox1.Text += "正在执行数据去重...\r\n";
            distinctList = waterList.DistinctBy(x => new { x.Name, x.Source }).ToList();
            richTextBox1.Text += $"数据去重已完成，去重后数据量为：{distinctList.Count}\r\n";
        }

private void button3_Click(object sender, EventArgs e)
        {
            richTextBox1.Text += "正在执行数据分类...\r\n";
            var Names = distinctList.Select(x => x.Name).Distinct().ToList();          
            for (int i = 0; i < Names.Count; i++)
            {
                var nameList = distinctList.Where(x => x.Name == Names[i]).ToList();
                if (nameList.Count > 50) 
                {
                    list.Add(nameList);
                }            
            }
            richTextBox1.Text += $"执行数据分类完成，类数为：{list.Count}\r\n";
        }

private void button4_Click(object sender, EventArgs e)
        {
            // 创建一个FolderBrowserDialog对象
            FolderBrowserDialog folderBrowserDialog = new FolderBrowserDialog();

// 设置对话框的标题
            folderBrowserDialog.Description = "选择保存各站点数据的文件夹";

// 设置默认的根文件夹，如果需要的话
            // folderBrowserDialog.RootFolder = Environment.SpecialFolder.MyComputer;

// 显示文件夹选择对话框
            DialogResult result = folderBrowserDialog.ShowDialog();

if (result == DialogResult.OK)
            {
                // 用户选择了一个文件夹
                selectedFolderPath = folderBrowserDialog.SelectedPath;
                richTextBox1.Text += $"选择的Excel保存文件夹为：{selectedFolderPath}\r\n";
                richTextBox1.Text += "正在执行导出为Excel文件...";
                using (ExcelPackage excelPackage = new ExcelPackage())
                {                 
                    for(int i =0; i < list.Count; i++) 
                    {
                        ExcelWorksheet worksheet = excelPackage.Workbook.Worksheets.Add(list[i][0].Name);
                        for (int j = 0; j < list[i].Count; j++)
                        {
                            worksheet.Cells[j + 1, 1].Value = list[i][j].Id;
                            worksheet.Cells[j + 1, 2].Value = list[i][j].Name;
                            worksheet.Cells[j + 1, 3].Value = list[i][j].WaterLevel;
                            worksheet.Cells[j + 1, 4].Value = list[i][j].WaterChange;
                            worksheet.Cells[j + 1, 5].Value = list[i][j].Source;
                        }
                    }

// 保存 Excel 文件
                    FileInfo excelFile = new FileInfo($"{selectedFolderPath}\\各站点数据.xlsx");
                    excelPackage.SaveAs(excelFile);
                    richTextBox1.Text += "导出为Excel文件完成\r\n";
                }
            }
        }
    }
}
```

https://www.cnblogs.com/lgx5/p/17865626.html