SQLHelper.cs类

using System;
using System.Data;
using System.Data.SqlClient;

namespace Microsoft.SqlHelper
{
    public static class SqlHelper
    {
        // 数据库连接字符串，替换为实际的连接字符串
        private static string connectionString = "Your_Connection_String_Here";

        /// <summary>
        /// 执行查询并返回结果集DataTable
        /// </summary>
        /// <param name="query">SQL查询语句</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="parameters">SQL参数数组</param>
        /// <returns>包含查询结果的DataTable</returns>
        public static DataTable ExecuteDataTable(string query, CommandType commandType, SqlParameter[] parameters = null)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand command = new SqlCommand(query, connection))
                {
                    command.CommandType = commandType;

                    if (parameters != null)
                    {
                        command.Parameters.AddRange(parameters);
                    }

                    using (SqlDataAdapter adapter = new SqlDataAdapter(command))
                    {
                        DataTable dataTable = new DataTable();
                        adapter.Fill(dataTable);
                        return dataTable;
                    }
                }
            }
        }

        /// <summary>
        /// 执行非查询SQL命令，返回受影响的行数
        /// </summary>
        /// <param name="query">SQL命令</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="parameters">SQL参数数组</param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(string query, CommandType commandType, SqlParameter[] parameters = null)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand command = new SqlCommand(query, connection))
                {
                    command.CommandType = commandType;

                    if (parameters != null)
                    {
                        command.Parameters.AddRange(parameters);
                    }

                    connection.Open();
                    return command.ExecuteNonQuery();
                }
            }
        }

        /// <summary>
        /// 执行查询并返回结果集的第一行第一列
        /// </summary>
        /// <param name="query">SQL查询语句</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="parameters">SQL参数数组</param>
        /// <returns>结果集的第一行第一列的值</returns>
        public static object ExecuteScalar(string query, CommandType commandType, SqlParameter[] parameters = null)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand command = new SqlCommand(query, connection))
                {
                    command.CommandType = commandType;

                    if (parameters != null)
                    {
                        command.Parameters.AddRange(parameters);
                    }

                    connection.Open();
                    return command.ExecuteScalar();
                }
            }
        }
    }
}