泛型反射ROM

这是一个通用的DBHelper的类文件

using System.Collections.Generic;
using System.Reflection;
using System.Data;
using System.Data.SqlClient;
using System.ComponentModel.DataAnnotations;

namespace Reflectiones
{
    public class DBHelper
    {
        /// <summary>
        /// 显示数据
        /// </summary>
        /// <param name=\"t\"></param>
        /// <returns></returns>
        public List<T> GetData<T>(T t) where T:class,new()
        {
            List<T> lst = new List<T>();

            var tf = typeof(T);
            string sql = \"SELECT * FROM\" + tf.Name;//Model层的类名
            DataTable dt = new DataTable();
            using (SqlConnection conn = new SqlConnection(\"\"))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn);
                SqlDataAdapter sda = new SqlDataAdapter(cmd);
                sda.Fill(dt);
            }

            PropertyInfo[] infos = tf.GetProperties();
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                 t = new T();
                foreach (var item in infos)
                {
                    item.SetValue(t, dt.Rows[i][item.Name]);
                }
                lst.Add(t);
            }
            return lst;
        }
        public int ComSqlCreate<T>(T t)where T:class,new()
        {
            var tf = typeof(T);
            string sql = \"INSERT INTO \" + tf.Name + \" VALUES(\";
            PropertyInfo[] infos = tf.GetProperties();
            foreach (var item in infos)
            {
                if (item.GetCustomAttribute(typeof(KeyAttribute),true) == null)
                {
                    sql += \"\'\" + item.GetValue(t, null) + \"\',\";
                }
                
            }
            sql += sql.TrimEnd(\',\') + \")\";
            using (SqlConnection conn = new SqlConnection(\"\"))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn);
                int n = cmd.ExecuteNonQuery();
                return n;
            }
        }
        /// <summary>
        /// 修改数据
        /// </summary>
        /// <typeparam name=\"T\"></typeparam>
        /// <param name=\"t\"></param>
        /// <returns></returns>
        public int ComSqlUpdate<T>(T t) where T:class,new()
        {
            var tf = typeof(T);
            string sql = \"UPDATE \" + tf.Name + \" SET \";
            string sqlWhere = \" WHERE \";
            PropertyInfo[] infos = tf.GetProperties();
            foreach (var item in infos)
            {
                if (item.Name == \"ID\")
                {
                    sqlWhere += \" WHERE \"+ item.Name + \" = \'\" + item.GetValue(t, null) + \"\'\";
                }
                else
                {
                    sql += item.Name + \" = \'\" + item.GetValue(t, null) + \"\',\";
                }
            }
            sql = sql.TrimEnd(\',\') + sqlWhere;
            using (SqlConnection conn = new SqlConnection(\"\"))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn);
                int n = cmd.ExecuteNonQuery();
                return n;
            }
        }
        /// <summary>
        /// 删除数据
        /// </summary>
        /// <typeparam name=\"T\"></typeparam>
        /// <param name=\"t\"></param>
        /// <returns></returns>
        public int ComSqlDelete<T>(T t)where T:class,new()
        {
            var tf = typeof(T);
            PropertyInfo[] infos = tf.GetProperties();
            string sql = \"DELETE FROM \" + tf.Name;
            foreach (var item in infos)
            {
                if (item.Name == \"ID\")
                {
                    sql += \" WHERE \" + item.Name + \" = \'\" + item.GetValue(t, null) + \"\'\";
                }
            }
            using (SqlConnection conn = new SqlConnection(\"\"))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn);
                int n = cmd.ExecuteNonQuery();
                return n;
            }
        }
    }
}