Linq 動態多條件group by

有個需求是要根據多個字段動態進行分組，具體效果如下

 

 

 

 平常一般用的都是根據具體的字段的取進行分組的，百度一下發現已有解決方案。https://www.cnblogs.com/devindong/p/3615625.html

第一種是直接用動態拼接分組條件，缺點在於如果是多個分組條件的話，分組條件將變得非常難寫，也很難寫全

private static dynamic GroupBy(dynamic r)
        {
            int a = 1, b = 2;

            if (a < b) return new { id = r.id};

            else if (a == b) return new { name=rd.name };

            else return new { a = r.a };
        }

還有一種是可以創建一個結構體來解決。需要注意的是，如果不用結構體而是選擇class的話需要重寫類的GetHashCode方法來重寫類的相等判斷方法。

該功能中構建的結構體為，根據相應的name group是為了拿key的時候取到對應的名稱

public struct MassPatternDesignGroup
    {
        /// <summary>
        ///     波段Id
        /// </summary>
        public Guid? BandId { get; set; }

        /// <summary>
        ///     波段名稱
        /// </summary>
        public string BandName { get; set; }

        /// <summary>
        ///     設計師Id
        /// </summary>
        public Guid? DesignerId { get; set; }

        /// <summary>
        ///     設計師
        /// </summary>
        public string DesignerName { get; set; }

        /// <summary>
        ///     品類Id
        /// </summary>
        public Guid? ProductCategoryId { get; set; }

        /// <summary>
        ///     品類名稱
        /// </summary>
        public string ProductCategoryName { get; set; }

        /// <summary>
        ///     主題Id
        /// </summary>
        public Guid? ThemePlanId { get; set; }

        /// <summary>
        ///     主題名稱
        /// </summary>
        public string ThemePlanName { get; set; }

        /// <summary>
        ///     系列Id
        /// </summary>
        public Guid? ProductSeriesId { get; set; }

        /// <summary>
        ///     系列名稱
        /// </summary>
        public string ProductSeriesName { get; set; }

        /// <summary>
        ///     廓形Id
        /// </summary>
        public Guid? SilhouetteId { get; set; }

        /// <summary>
        ///     廓形名稱
        /// </summary>
        public string SilhouetteName { get; set; }

        /// <summary>
        ///     款式來源Id
        /// </summary>
        public Guid? PatternPropertyId { get; set; }

        /// <summary>
        ///      款式來源名稱
        /// </summary>
        public string PatternPropertyName { get; set; }

        /// <summary>
        ///     銷售渠道Id
        /// </summary>
        public Guid? SalesChannelsId { get; set; }

        /// <summary>
        ///     銷售渠道名稱
        /// </summary>
        public string SalesChannelsName { get; set; }

        public string GetKey()
        {
            return
                $"{BandName} {DesignerName} {ProductCategoryName} {ThemePlanName} {ProductSeriesName} {SilhouetteName} {PatternPropertyName} {SalesChannelsName}";
        }
    }

其中GetKey方法為獲取分組條件。

group的model類為

public class MassPatternDesignGroupModel
    {
        /// <summary>
        /// 波段
        /// </summary>
        public bool Band { get; set; }

        /// <summary>
        /// 設計師
        /// </summary>
        public bool Designer { get; set; }

        /// <summary>
        /// 品類
        /// </summary>
        public bool ProductCategory { get; set; }

        /// <summary>
        ///  主題
        /// </summary>
        public bool ThemePlan { get; set; }

        /// <summary>
        /// 系列
        /// </summary>
        public bool ProductSeries { get; set; }

        /// <summary>
        /// 廓形
        /// </summary>
        public bool Silhouette { get; set; }

        /// <summary>
        /// 款式來源
        /// </summary>
        public bool PatternProperty { get; set; }

        /// <summary>
        /// 銷售渠道
        /// </summary>
        public bool SalesChannels { get; set; }

        /// <summary>
        ///     品牌Id
        /// </summary>
        public Guid BrandId { get; set; }

        /// <summary>
        ///     年份
        /// </summary>
        public int Year { get; set; }

        /// <summary>
        ///     季節Id
        /// </summary>
        public Guid SeasonId { get; set; }

        /// <summary>
        ///     機構Id
        /// </summary>
        public Guid OrganizationId { get; set; }

        public MassPatternDesignGroup GroupBy(dynamic r)
        {
            var g = new MassPatternDesignGroup();
            if (Band)
            {
                g.BandId=r.BandId;
                g.BandName=r.BandName;
            }

            if (Designer)
            {
                g.DesignerId = r.DesignerId;
                g.DesignerName = r.DesignerName;
            }

            if (ProductCategory)
            {
                g.ProductCategoryId = r.ProductCategoryId;
                g.ProductCategoryName = r.ProductCategoryName;
            }

            if (ThemePlan)
            {
                g.ThemePlanId = r.ThemePlanId;
                g.ThemePlanName = r.ThemePlanName;
            }

            if (ProductSeries)
            {
                g.ProductSeriesId = r.ProductSeriesId;
                g.ProductSeriesName = r.ProductSeriesName;
            }

            if (Silhouette)
            {
                g.SilhouetteId = r.SilhouetteId;
                g.SilhouetteName = r.SilhouetteName;
            }

            if (PatternProperty)
            {
                g.PatternPropertyId = r.PatternPropertyId;
                g.PatternPropertyName = r.PatternPropertyName;
            }

            if (SalesChannels)
            {
                g.SalesChannelsId = r.SalesChannelsId;
                g.SalesChannelsName = r.SalesChannelsName;
            }

            return g;
        }

     
    }

其中的字段是前台傳過來的分組項，分組時通過MassPatternDesignGroupModel調用GroupBy方法進行動態的多條件分組。

具體的調用如下

public ActionResult GetList(MassPatternDesignGroupModel model)
        {
            var result = new List<MassPatternDesignGroupQueryPanelDto>();
            var massPatternDesignGroups = _designGroupQueryService.GetMassPatternDesignGroupQueryList(model.BrandId, model.Year, model.SeasonId, model.OrganizationId);
            var list= massPatternDesignGroups.GroupBy(a => model.GroupBy(a)).ToList();//動態分組
            list.ForEach(a =>
            {
                var dto=new MassPatternDesignGroupQueryPanelDto()
                {
                    Title = a.Key.GetKey(),
                    Items = a.OrderBy(b=>b.UUID).ToList()
                };
                dto.TaskCount = dto.Items.Count(b => b.Type == MassPatternDesignGroupQueryType.任務);
                dto.DesignCount = dto.Items.Count(b => b.Type == MassPatternDesignGroupQueryType.設計);
                dto.ProofCount = dto.Items.Count(b => b.Type == MassPatternDesignGroupQueryType.打樣);
                dto.MassCount = dto.Items.Count(b => b.Type == MassPatternDesignGroupQueryType.選款);

                result.Add(dto);
            });
            return this.Direct(result);
        }

 

 以上，就實現了Linq to Object多條件動態分組了。