使用pivot c#将DGV或DataTable导出到Excel文件

using System;
using System.Data;
using System.IO;
using OfficeOpenXml;
using OfficeOpenXml.Table;

public static class ExcelExporter
{
    public static void ExportToExcel(DataGridView dgv, string filePath)
    {
        DataTable dt = GetDataTableFromDGV(dgv);
        ExportToExcel(dt, filePath);
    }

    public static void ExportToExcel(DataTable dt, string filePath)
    {
        using (ExcelPackage package = new ExcelPackage())
        {
            ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Sheet1");

            // 将DataTable数据写入ExcelWorksheet
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                worksheet.Cells[1, i + 1].Value = dt.Columns[i].ColumnName;
            }

            for (int row = 0; row < dt.Rows.Count; row++)
            {
                for (int col = 0; col < dt.Columns.Count; col++)
                {
                    worksheet.Cells[row + 2, col + 1].Value = dt.Rows[row][col];
                }
            }

            // 创建透视表
            ExcelRangeBase dataRange = worksheet.Cells[worksheet.Dimension.Address];
            ExcelTable table = worksheet.Tables.Add(dataRange, "PivotTable");
            table.TableStyle = TableStyles.Medium2;

            // 设置透视表字段
            ExcelPivotTable pivotTable = worksheet.PivotTables.Add(worksheet.Cells["E1"], table, "PivotTable");
            pivotTable.RowFields.Add(pivotTable.Fields["Column1"]);
            pivotTable.ColumnFields.Add(pivotTable.Fields["Column2"]);
            pivotTable.DataFields.Add(pivotTable.Fields["Column3"]);

            // 保存Excel文件
            FileInfo file = new FileInfo(filePath);
            package.SaveAs(file);
        }
    }

    private static DataTable GetDataTableFromDGV(DataGridView dgv)
    {
        DataTable dt = new DataTable();
        
        // 创建列
        for (int i = 0; i < dgv.Columns.Count; i++)
        {
            dt.Columns.Add(dgv.Columns[i].HeaderText);
        }

        // 添加行数据
        foreach (DataGridViewRow row in dgv.Rows)
        {
            DataRow dr = dt.NewRow();
            for (int i = 0; i < dgv.Columns.Count; i++)
            {
                dr[i] = row.Cells[i].Value;
            }
            dt.Rows.Add(dr);
        }

        return dt;
    }
}

// 导出DataGridView到Excel文件
DataGridView dgv = new DataGridView();
// 添加数据到DataGridView
// ...

string filePath = "path/to/file.xlsx";
ExcelExporter.ExportToExcel(dgv, filePath);