C# ADO.NET+反射读取数据库并转换为List

 public List<T> QueryByADO<T>(string connStr, string sql) where T : class, new()
        {
            using (SqlConnection conn = new SqlConnection())
            {
                try
                {
                    conn.ConnectionString = connStr;
                    conn.Open();
                    SqlDataAdapter myda = new SqlDataAdapter(sql, conn);
                    DataTable dt = new DataTable();
                    myda.Fill(dt);
                    return ConvertToModel<T>(dt);
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    conn.Close();
                }
            }
        }

        /// <summary>
        /// 将DataTable数据源转换成实体类
        /// </summary>
        public List<T> ConvertToModel<T>(DataTable dt) where T : class, new()
        {
            List<T> ts = new List<T>();// 定义集合
            foreach (DataRow dr in dt.Rows)
            {
                T t = new T();
                PropertyInfo[] propertys = t.GetType().GetProperties();// 获得此模型的公共属性
                foreach (PropertyInfo pi in propertys)
                {
                    if (dt.Columns.Contains(pi.Name))
                    {
                        if (!pi.CanWrite) continue;
                        var value = dr[pi.Name];
                        if (value != DBNull.Value)
                        {
                            if (pi.PropertyType.FullName.Contains("System.Nullable"))
                            {
                                pi.SetValue(t, Convert.ChangeType(value, (Nullable.GetUnderlyingType(pi.PropertyType) ?? pi.PropertyType)), null);
                            }
                            else
                            {
                                switch (pi.PropertyType.FullName)
                                {
                                    case "System.Decimal":
                                        pi.SetValue(t, decimal.Parse(value.ToString()), null);
                                        break;
                                    case "System.String":
                                        pi.SetValue(t, value.ToString(), null);
                                        break;
                                    case "System.Char":
                                        pi.SetValue(t, Convert.ToChar(value), null);
                                        break;
                                    case "System.Guid":
                                        pi.SetValue(t,value, null);
                                        break;
                                    case "System.Int16":
                                        pi.SetValue(t, Convert.ToInt16(value), null);
                                        break;
                                    case "System.Int32":
                                        pi.SetValue(t, int.Parse(value.ToString()), null);
                                        break;
                                    case "System.Int64":
                                        pi.SetValue(t, Convert.ToInt64(value), null);
                                        break;
                                    case "System.Byte[]":
                                        pi.SetValue(t, Convert.ToByte(value), null);
                                        break;
                                    case "System.Boolean":
                                        pi.SetValue(t,Convert.ToBoolean(value), null);
                                        break;
                                    case "System.Double":
                                        pi.SetValue(t, Convert.ToDouble(value.ToString()), null);
                                        break;
                                    case "System.DateTime":
                                        pi.SetValue(t, value ?? Convert.ToDateTime(value), null);
                                        break;
                                    default:
                                        throw new Exception("类型不匹配:" + pi.PropertyType.FullName);
                                }
                            }
                        }
                    }
                }
                ts.Add(t);
            }
            return ts;
        }

　　

 public List<T> QueryByADO<T>(string connStr, string sql) where T : class, new()
        {
            using (SqlConnection conn = new SqlConnection())
            {
                try
                {
                    conn.ConnectionString = connStr;
                    conn.Open();
                    SqlDataAdapter myda = new SqlDataAdapter(sql, conn);
                    DataTable dt = new DataTable();
                    myda.Fill(dt);
                    return ConvertToModel<T>(dt);
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    conn.Close();
                }
            }
        }

        /// <summary>
        /// 将DataTable数据源转换成实体类
        /// </summary>
        public List<T> ConvertToModel<T>(DataTable dt) where T : class, new()
        {
            List<T> ts = new List<T>();// 定义集合
            foreach (DataRow dr in dt.Rows)
            {
                T t = new T();
                PropertyInfo[] propertys = t.GetType().GetProperties();// 获得此模型的公共属性
                foreach (PropertyInfo pi in propertys)
                {
                    if (dt.Columns.Contains(pi.Name))
                    {
                        if (!pi.CanWrite) continue;
                        var value = dr[pi.Name];
                        if (value != DBNull.Value)
                        {
                            if (!pi.PropertyType.IsGenericType)
                            {
                                //非泛型
                                pi.SetValue(t, value==null ? null : Convert.ChangeType(value, pi.PropertyType), null);
                            }
                            else
                            {
                                //泛型Nullable<>
                                Type genericTypeDefinition = pi.PropertyType.GetGenericTypeDefinition();
                                if (genericTypeDefinition == typeof(Nullable<>))
                                {
                                    pi.SetValue(t, value == null ? null : Convert.ChangeType(value, Nullable.GetUnderlyingType(pi.PropertyType)), null);
                                }
                            }
                        }
                    }
                }
                ts.Add(t);
            }
            return ts;
        }
//参考连接 https://blog.csdn.net/xiaohan2826/article/details/8536074