在C#中使用> 255列的SQL Csv的有效方法？

using System;
using System.Data.SqlClient;
using System.IO;
using System.Text;

public class CsvImporter
{
    public void ImportCsv(string csvFilePath, string connectionString)
    {
        // 创建临时表
        string createTableSql = "CREATE TABLE #TempTable (Column1 VARCHAR(MAX), Column2 VARCHAR(MAX), ...)";
        
        // 读取CSV文件内容
        string[] lines = File.ReadAllLines(csvFilePath);
        
        // 构建INSERT语句
        StringBuilder insertSqlBuilder = new StringBuilder();
        insertSqlBuilder.AppendLine("INSERT INTO #TempTable (Column1, Column2, ...) VALUES");
        foreach (string line in lines)
        {
            string[] fields = line.Split(',');
            insertSqlBuilder.AppendLine($"('{fields[0]}', '{fields[1]}', ...),");
        }
        string insertSql = insertSqlBuilder.ToString().TrimEnd(',') + ";";
        
        // 连接到数据库并执行INSERT语句
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            
            using (SqlCommand command = new SqlCommand(createTableSql, connection))
            {
                command.ExecuteNonQuery();
            }
            
            using (SqlCommand command = new SqlCommand(insertSql, connection))
            {
                command.ExecuteNonQuery();
            }
            
            // 使用MERGE语句将临时表中的数据合并到目标表中
            string mergeSql = "MERGE INTO TargetTable AS T USING #TempTable AS S ON T.PrimaryKey = S.PrimaryKey WHEN MATCHED THEN UPDATE SET T.Column1 = S.Column1, T.Column2 = S.Column2, ... WHEN NOT MATCHED THEN INSERT (Column1, Column2, ...) VALUES (S.Column1, S.Column2, ...);";
            using (SqlCommand command = new SqlCommand(mergeSql, connection))
            {
                command.ExecuteNonQuery();
            }
            
            // 删除临时表
            string dropTableSql = "DROP TABLE #TempTable;";
            using (SqlCommand command = new SqlCommand(dropTableSql, connection))
            {
                command.ExecuteNonQuery();
            }
        }
    }
}