严重性代码说明项目文件行抑制状态错误

我有3个错误，我无法管理这个 . 请帮我解决一下 .

谢谢，

劳尔

严重级代码描述项目文件行抑制状态错误CS0029无法将类型'System.Data.SqlClient.SqlCommand'隐式转换为'System.Data.SqlClient.SqlConnection'网站严重级代码说明项目文件行抑制状态错误CS1061'SqlConnection'不包含'CommandText'的定义，并且没有扩展方法'CommandText'接受类型为'SqlConnection'的第一个参数'（您是否缺少using指令或汇编引用？）严重性代码描述项目文件行抑制状态错误CS1061' SqlConnection'不包含'ExecuteReader'的定义，并且没有可以找到接受类型'SqlConnection'的第一个参数的扩展方法'ExecuteReader'（您是否缺少using指令或程序集引用？）

using System;
    using System.Collections.Generic;
    using System.Data.SqlClient;
    using System.Configuration;
    using System.Linq;
    using System.Web;
    using System.Collections;

    namespace Website
    {
        public static class ConnectionClass
        {
            private static SqlConnection conn;
            private static SqlConnection command;

            static ConnectionClass()
            {
                string connectionString = ConfigurationManager.ConnectionStrings["tigariConnection"].ToString();
                conn = new SqlConnection(connectionString);
                command = new SqlCommand("",conn);
            }

            public static ArrayList GetTigariByType(string tigariType)
            {
                ArrayList list = new ArrayList();
                string query = string.Format("SELECT * FROM tigari WHERE type LIKE '{0}'", tigariType);
                try
                {
                    conn.Open();
                    command.CommandText = query;
                    SqlDataReader reader = command.ExecuteReader();

                    while(reader.Read())
                    {
                        int id = reader.GetInt32(0);
                        string name = reader.GetString(1);
                        string type = reader.GetString(2);
                        double price = reader.GetDouble(3);
                        string country = reader.GetString(4);
                        string image = reader.GetString(5);
                        string review = reader.GetString(6);

                        Tigari tigari = new Tigari(id, name, type, price, country, image, review);
                        list.Add(tigari);

                    }
                }
                finally
                {
                    conn.Close();
                }
                return list;
            }
        }
    }