.net数据库导入导出

using System;
using System.IO;
using System.Linq;
using System.Data.SqlClient;

public void ExportToCSV(string connectionString, string tableName, string filePath)
{
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        connection.Open();
        string query = $"SELECT * FROM {tableName}";
        using (SqlCommand command = new SqlCommand(query, connection))
        {
            using (SqlDataReader reader = command.ExecuteReader())
            {
                using (StreamWriter file = new StreamWriter(filePath))
                {
                    // 写入列名
                    for (int i = 0; i < reader.FieldCount; i++)
                    {
                        file.Write(reader.GetName(i));
                        if (i < reader.FieldCount - 1)
                            file.Write(",");
                        else
                            file.WriteLine();
                    }

                    // 写入数据行
                    while (reader.Read())
                    {
                        for (int i = 0; i < reader.FieldCount; i++)
                        {
                            file.Write(reader[i].ToString().Replace(",", ";"));
                            if (i < reader.FieldCount - 1)
                                file.Write(",");
                            else
                                file.WriteLine();
                        }
                    }
                }
            }
        }
    }
}