HENGCHENG/DSWeb/Areas/MvcShipping/Helper/AutoMapperHelper.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq.Expressions;
using System.Reflection;
using AutoMapper;

namespace DSWeb.Areas.MvcShipping.Helper
{
    /// <summary>
    /// AutoMapper的帮助类
    /// </summary>
    public static class AutoMapperHelper
    {
        /// <summary>
        /// 来源，目标
        /// 单条实体类型映射,默认字段名字一一对应
        /// 
        /// </summary>
        /// <typeparam name="TSource">Dto类型</typeparam>
        /// <typeparam name="TDestination">要被转化的数据</typeparam>
        /// <param name="source">转化之后的实体</param>
        /// <returns></returns>
        public static TDestination MapTo<TSource, TDestination>(this TSource source)
            where TDestination : class, new()
            where TSource : class
        {
            if (source == null) return new TDestination();
            var config = new MapperConfiguration(cfg => cfg.CreateMap<TSource, TDestination>());
            var mapper = config.CreateMapper();
            return mapper.Map<TDestination>(source);
        }

        /// <summary>
        /// 实体列表类型映射,默认字段名字一一对应
        /// </summary>
        /// <typeparam name="TDestination">Dto类型</typeparam>
        /// <typeparam name="TSource">要被转化的数据</typeparam>
        /// <param name="source">可以使用这个扩展方法的类型，任何引用类型</param>
        /// <returns>转化之后的实体列表</returns>
        public static List<TDestination> MapToList<TSource, TDestination>(this IEnumerable<TSource> source)
            where TDestination : class
            where TSource : class
        {
            if (source == null) return new List<TDestination>();
            var config = new MapperConfiguration(cfg => cfg.CreateMap<TSource, TDestination>());
            var mapper = config.CreateMapper();
            return mapper.Map<List<TDestination>>(source);
        }

    }


    /// <summary>
    /// 
    /// </summary>
    public class Query
    {
        public enum Operators
        {
            None = 0,
            Equal = 1,
            GreaterThan = 2,
            GreaterThanOrEqual = 3,
            LessThan = 4,
            LessThanOrEqual = 5,
            Contains = 6,
            StartWith = 7,
            EndWidth = 8,
            Range = 9
        }
        public enum Condition
        {
            OrElse = 1,
            AndAlso = 2
        }
        public string Name { get; set; }
        public Operators Operator { get; set; }
        public object Value { get; set; }
        public object ValueMin { get; set; }
        public object ValueMax { get; set; }
    }

    /// <summary>
    /// 动态拼接lamba子句
    /// 典型调用方式：
    ///                 //找到所有需要盘点的库存
    ///    List<VW_OP_WMS_AREAGOODS> 符合条件的在库库存 = new List<VW_OP_WMS_AREAGOODS>();

    ///    QueryCollection queries = new QueryCollection();

    ///    if(!string.IsNullOrWhiteSpace(head.CUSTOMERNAME))
    ///       queries.Add(new Query { Name = "CUSTOMERNAME", Operator = Query.Operators.Equal, Value = head.CUSTOMERNAME
    ///     });
    ///if (!string.IsNullOrWhiteSpace(head.STOREHOUSE))
    ///    queries.Add(new Query { Name = "STOREHOUSE", Operator = Query.Operators.Equal, Value = head.STOREHOUSE });
    ///if (!string.IsNullOrWhiteSpace(head.GOODSOWNER))
    ///    queries.Add(new Query { Name = "GOODSOWNER", Operator = Query.Operators.Equal, Value = head.GOODSOWNER });
    ///if (!string.IsNullOrWhiteSpace(head.AREACODE))
    ///    queries.Add(new Query { Name = "AREACODE", Operator = Query.Operators.StartWith, Value = head.AREACODE });

    ///符合条件的在库库存 = VW_OP_WMS_AREAGOODSRepository.Instance.FindAsIQueryable(queries.AsExpression<VW_OP_WMS_AREAGOODS>(Query.Condition.AndAlso)).ToList();
    /// </summary>
public class QueryCollection : Collection<Query>
    {
        public Expression<Func<T, bool>> AsExpression<T>(Query.Condition? condition = Query.Condition.OrElse) where T : class
        {
            Type targetType = typeof(T);
            TypeInfo typeInfo = targetType.GetTypeInfo();
            var parameter = Expression.Parameter(targetType, "m");
            Expression expression = null;
            Func<Expression, Expression, Expression> Append = (exp1, exp2) =>
            {
                if (exp1 == null)
                {
                    return exp2;
                }
                return (condition ?? Query.Condition.OrElse) == Query.Condition.OrElse ? Expression.OrElse(exp1, exp2) : Expression.AndAlso(exp1, exp2);
            };
            foreach (var item in this)
            {
                var property = typeInfo.GetProperty(item.Name);
                if (property == null ||
                    !property.CanRead ||
                    (item.Operator != Query.Operators.Range && item.Value == null) ||
                    (item.Operator == Query.Operators.Range && item.ValueMin == null && item.ValueMax == null))
                {
                    continue;
                }
                Type realType = Nullable.GetUnderlyingType(property.PropertyType) ?? property.PropertyType;
                if (item.Value != null)
                {
                    item.Value = Convert.ChangeType(item.Value, realType);
                }
                Expression<Func<object>> valueLamba = () => item.Value;
                switch (item.Operator)
                {
                    case Query.Operators.Equal:
                        {
                            expression = Append(expression, Expression.Equal(Expression.Property(parameter, item.Name),
                                Expression.Convert(valueLamba.Body, property.PropertyType)));
                            break;
                        }
                    case Query.Operators.GreaterThan:
                        {
                            expression = Append(expression, Expression.GreaterThan(Expression.Property(parameter, item.Name),
                                Expression.Convert(valueLamba.Body, property.PropertyType)));
                            break;
                        }
                    case Query.Operators.GreaterThanOrEqual:
                        {
                            expression = Append(expression, Expression.GreaterThanOrEqual(Expression.Property(parameter, item.Name),
                                Expression.Convert(valueLamba.Body, property.PropertyType)));
                            break;
                        }
                    case Query.Operators.LessThan:
                        {
                            expression = Append(expression, Expression.LessThan(Expression.Property(parameter, item.Name),
                                Expression.Convert(valueLamba.Body, property.PropertyType)));
                            break;
                        }
                    case Query.Operators.LessThanOrEqual:
                        {
                            expression = Append(expression, Expression.LessThanOrEqual(Expression.Property(parameter, item.Name),
                                Expression.Convert(valueLamba.Body, property.PropertyType)));
                            break;
                        }
                    case Query.Operators.Contains:
                        {
                            var nullCheck = Expression.Not(Expression.Call(typeof(string), "IsNullOrEmpty", null, Expression.Property(parameter, item.Name)));
                            var contains = Expression.Call(Expression.Property(parameter, item.Name), "Contains", null,
                                Expression.Convert(valueLamba.Body, property.PropertyType));
                            expression = Append(expression, Expression.AndAlso(nullCheck, contains));
                            break;
                        }
                    case Query.Operators.StartWith:
                        {
                            var nullCheck = Expression.Not(Expression.Call(typeof(string), "IsNullOrEmpty", null, Expression.Property(parameter, item.Name)));
                            var startsWith = Expression.Call(Expression.Property(parameter, item.Name), "StartsWith", null,
                                Expression.Convert(valueLamba.Body, property.PropertyType));
                            expression = Append(expression, Expression.AndAlso(nullCheck, startsWith));
                            break;
                        }
                    case Query.Operators.EndWidth:
                        {
                            var nullCheck = Expression.Not(Expression.Call(typeof(string), "IsNullOrEmpty", null, Expression.Property(parameter, item.Name)));
                            var endsWith = Expression.Call(Expression.Property(parameter, item.Name), "EndsWith", null,
                                Expression.Convert(valueLamba.Body, property.PropertyType));
                            expression = Append(expression, Expression.AndAlso(nullCheck, endsWith));
                            break;
                        }
                    case Query.Operators.Range:
                        {
                            Expression minExp = null, maxExp = null;
                            if (item.ValueMin != null)
                            {
                                var minValue = Convert.ChangeType(item.ValueMin, realType);
                                Expression<Func<object>> minValueLamda = () => minValue;
                                minExp = Expression.GreaterThanOrEqual(Expression.Property(parameter, item.Name), Expression.Convert(minValueLamda.Body, property.PropertyType));
                            }
                            if (item.ValueMax != null)
                            {
                                var maxValue = Convert.ChangeType(item.ValueMax, realType);
                                Expression<Func<object>> maxValueLamda = () => maxValue;
                                maxExp = Expression.LessThanOrEqual(Expression.Property(parameter, item.Name), Expression.Convert(maxValueLamda.Body, property.PropertyType));
                            }

                            if (minExp != null && maxExp != null)
                            {
                                expression = Append(expression, Expression.AndAlso(minExp, maxExp));
                            }
                            else if (minExp != null)
                            {
                                expression = Append(expression, minExp);
                            }
                            else if (maxExp != null)
                            {
                                expression = Append(expression, maxExp);
                            }

                            break;
                        }
                }
            }
            if (expression == null)
            {
                return null;
            }
            return ((Expression<Func<T, bool>>)Expression.Lambda(expression, parameter));
        }
    }
}