产品搜索算法最佳实践

Question

我关心的是根据UI选择进行搜索。例如，我将搜索具有许多参数的产品，代码如下所示

if(param1 != null && param1 == 1 && param2 != null && param2 == 2 && param3 != null && paaram3 == 3)
{
}
else if(param1 != null && param1 == 1 && param2 != null && param2 == 2)
{
}
else if(param1 != null && param1 == 1)

最好的方法应该是这样的，因为有很多的可能性，就像一个polinom。

这应该有一种方式，谓词等。我不想写这样的代码

public ActionResult SearchProductVehicle(string CatagoryId, string MarkId, string ModelId, string HomeCat6,
    string productFuelType, string productCaseType, string productGearType, string fader1, string fader2, string fader3, string fader4, string startPrice, string endPrice,
string hdnInpSearch)
{
    if (CatagoryId == "-1")
    {
        List<Product> prdcs = Session["BeforeProducts"] as List<Product>;
        return View(new HomeViewModel
        {
            listpG = context.ProductGroups.ToList(),
            listCatG = context.Categories.ToList(),
            listMarks = context.Marks.ToList(),
            currencies = context.Currencies.ToList(),
            products = prdcs,
            cities = context.Cities.ToList(),
            listFuelTypes = context.FuelTypes.ToList(),
            listCaseTypes = context.CaseTypes.ToList(),
            listGearTypes = context.GearTypes.ToList()
        });
    }

    var products = new List<Product>();

    if (hdnInpSearch == null)
    {
        hdnInpSearch = string.Empty;
    }
    hdnInpSearch = hdnInpSearch.TrimStart().TrimEnd();
    if (hdnInpSearch == "Parça kodu, adı ya da açıklamasında" || hdnInpSearch == "İlan başlığı ya da açıklamasında" || hdnInpSearch == "Hizmet adı ya da açıklamasında")
    {
        hdnInpSearch = string.Empty;
    }

    var criteria = hdnInpSearch.Split(' ');

    var qry = string.Empty;

    // paged query should be ignore the other parameters
    if (Request.QueryString["page"] != null && Convert.ToInt32(Request.QueryString["page"]) > 1)
    {
        CatagoryId = "";
        MarkId = "null";
        ModelId = "null";
        HomeCat6 = "null";
    }

    if (HomeCat6 == null)
    {
        qry = HttpContext.Request.Url.AbsoluteUri + "?CatagoryId=" + CatagoryId + "&MarkId=" + MarkId + "&ModelId=" + ModelId + "&HomeCat6=" + HomeCat6 + "&hdnInpSearch=" + hdnInpSearch;
        Int32.TryParse(MarkId, out marId);
        //var marId = Convert.ToInt32(MarkId);
        var fChilds = context.Categories.Where(k => k.Id == marId).Select(m => m.Id).ToList();


        foreach (object obj in fChilds)
            types1.Add(Convert.ToInt32(obj));

        var sChilds = context.Categories.Where(k => types1.Contains(k.ParentId)).Select(m => m.Id).ToList();

        foreach (object obj in sChilds)
            types2.Add(Convert.ToInt32(obj));

        var tChilds = context.Categories.Where(k => types2.Contains(k.ParentId)).Select(m => m.Id).ToList();

        foreach (object obj in tChilds)
            types3.Add(Convert.ToInt32(obj));

        types3.Add(marId);
        crit = criteria[0].ToString();
        products = context.Products.Where(K => K.ProductType == 1 && K.IsActive == true && types3.Contains(K.CategoryId) && (K.Name.Contains(crit) || crit == string.Empty || crit == string.Empty)).Take(500).ToList();
    }
    else
    {
        if (CatagoryId != "null" && MarkId != "null" && ModelId != "null" && HomeCat6 != "null")
        {
            Debug.Assert(HttpContext.Request.Url != null, "HttpContext.Request.Url != null");
            qry = HttpContext.Request.Url.AbsoluteUri + "?CatagoryId=" + CatagoryId + "&MarkId=" + MarkId + "&ModelId=" + ModelId + "&HomeCat6=" + HomeCat6 + "&hdnInpSearch=" + hdnInpSearch;
            var subModId = Convert.ToInt32(HomeCat6);
            var fChilds = context.Categories.Where(k => k.Id == subModId).Select(m => m.Id).ToList();
            var types1 = fChilds.Select(fc => (int?)fc).ToList();
            var crit = criteria[0].ToString();
            products = context.Products.Where(K => K.ProductType == 1 && K.IsActive == true && types1.Contains(K.CategoryId) && (K.Name.Contains(crit) || crit == string.Empty)).Take(500).ToList();
        }
        else
        {
            if (CatagoryId != "null" && MarkId != "null" && ModelId != "null")
            {
                qry = HttpContext.Request.Url.AbsoluteUri + "?CatagoryId=" + CatagoryId + "&MarkId=" + MarkId + "&ModelId=" + ModelId + "&HomeCat6=" + HomeCat6 + "&hdnInpSearch=" + hdnInpSearch;
                var modId = Convert.ToInt32(ModelId);
                var fChilds = context.Categories.Where(k => k.Id == modId).Select(m => m.Id).ToList();
                var types1 = fChilds.Select(fc => (int?)fc).ToList();

                var sChilds = context.Categories.Where(k => types1.Contains(k.ParentId)).Select(m => m.Id).ToList();
                var types2 = sChilds.Select(sc => (int?)sc).ToList();
                types2.Add(modId);
                var crit = criteria[0].ToString();
                products = context.Products.Where(K => K.ProductType == 1 && K.IsActive == true && types2.Contains(K.CategoryId) && (K.Name.Contains(crit) || crit == string.Empty)).Take(500).ToList();
            }
            else
            {
                if (CatagoryId != "null" && MarkId != "null" && HomeCat6 == "null")
                {
                    qry = HttpContext.Request.Url.AbsoluteUri + "?CatagoryId=" + CatagoryId + "&MarkId=" + MarkId + "&ModelId=" + ModelId + "&HomeCat6=" + HomeCat6 + "&hdnInpSearch=" + hdnInpSearch;
                    Int32.TryParse(MarkId, out marId);
                    //var marId = Convert.ToInt32(MarkId);
                    var fChilds = context.Categories.Where(k => k.Id == marId).Select(m => m.Id).ToList();


                    foreach (object obj in fChilds)
                        types1.Add(Convert.ToInt32(obj));

                    var sChilds = context.Categories.Where(k => types1.Contains(k.ParentId)).Select(m => m.Id).ToList();

                    foreach (object obj in sChilds)
                        types2.Add(Convert.ToInt32(obj));

                    var tChilds = context.Categories.Where(k => types2.Contains(k.ParentId)).Select(m => m.Id).ToList();

                    foreach (object obj in tChilds)
                        types3.Add(Convert.ToInt32(obj));

                    types3.Add(marId);
                    crit = criteria[0].ToString();
                    products = context.Products.Where(K => K.ProductType == 1 && K.IsActive == true && types3.Contains(K.CategoryId) && (K.Name.Contains(crit) || crit == string.Empty || crit == string.Empty)).Take(500).ToList();
                }
                else
                {
                    if (CatagoryId != "null" && MarkId == "null" && ModelId == "null" && HomeCat6 == "null")
                    {
                        qry = HttpContext.Request.Url.AbsoluteUri + "?CatagoryId=" + CatagoryId + "&MarkId=" + MarkId + "&ModelId=" + ModelId + "&HomeCat6=" + HomeCat6 + "&hdnInpSearch=" + hdnInpSearch;
                        var crit = criteria[0].ToString();
                        products = context.Products.Where(K => K.ProductType == 1 && K.IsActive == true && (K.Name.Contains(crit) || crit == string.Empty)).Take(500).ToList();
                    }
                    else
                    {
                        if (CatagoryId == "null" && MarkId == "null" && ModelId == "null" && HomeCat6 == "null")
                        {
                            qry = HttpContext.Request.Url.AbsoluteUri + "?CatagoryId=" + CatagoryId + "&hdnInpSearch=" + hdnInpSearch;

                            if (criteria[0] != string.Empty)
                            {
                                var tempPro1 = new List<Product>();

                                foreach (var sCriteria in criteria)
                                {
                                    var criteria1 = sCriteria;
                                    tempPro1.AddRange(context.Products.Where(k => k.ProductType == 1 && k.IsActive == true && k.Name.Contains(criteria1)).ToList());
                                    tempPro1.AddRange(context.Products.Where(k => k.ProductType == 1 && k.IsActive == true && k.Explanation.Contains(sCriteria)).ToList());
                                }
                                products = tempPro1.OrderByDescending(m => m.RecordDate).Take(500).ToList();
                            }
                        }
                    }
                }
            }
        }
    }

    if (!HttpContext.Request.UrlReferrer.AbsoluteUri.Contains("SearchProduct"))
    {
        HttpContext.Session["qry"] = qry;
    }
    if (HttpContext.Request.UrlReferrer.AbsoluteUri.Contains("GeneralSearch"))
    {
        HttpContext.Session["qry"] = HttpContext.Request.UrlReferrer.AbsoluteUri;
    }
    else
    {
    }

    if (!products.Any() && CatagoryId == "null" && MarkId == "null" && ModelId == "null" && HomeCat6 == "null")
    {
        products = context.Products.Where(k => k.ProductType == 1 && k.IsActive == true).OrderByDescending(m => m.Id).Take(100).ToList();
    }

    if (productFuelType != null)
    {

        if (productFuelType.Trim() != "1")
        {
            var fuelType = Convert.ToInt32(productFuelType);
            products = products.Where(k => k.FuelType == fuelType).ToList();
        }
        if (productCaseType.Trim() != "1")
        {
            var caseType = Convert.ToInt32(productCaseType);
            products = products.Where(k => k.CaseType == caseType).ToList();
        }
        if (productGearType.Trim() != "1")
        {
            var gearType = Convert.ToInt32(productGearType);
            products = products.Where(k => k.GearType == gearType).ToList();
        }

        if (fader1.Trim() != "1960")
        {
            var modelYearStart = Convert.ToInt32(fader1);
            products = products.Where(k => Convert.ToInt32(k.ModelYear) >= modelYearStart).ToList();
        }
        if (fader2.Trim() != "2015")
        {
            var modelYearEnd = Convert.ToInt32(fader2);
            products = products.Where(k => Convert.ToInt32(k.ModelYear) <= modelYearEnd).ToList();
        }

        if (fader3.Trim() != "750")
        {
            var engineStart = Convert.ToInt32(fader3);
            products = products.Where(k => k.EngineCapacity >= engineStart).ToList();
        }
        if (fader4.Trim() != "10000")
        {
            var engineEnd = Convert.ToInt32(fader4);
            products = products.Where(k => k.EngineCapacity <= engineEnd).ToList();
        }

        if (startPrice.Trim() != string.Empty)
        {
            var priceStart = Convert.ToInt32(startPrice);
            products = products.Where(k => k.CurrentPrice >= priceStart).ToList();
        }
        if (endPrice != null && endPrice.Trim() != string.Empty)
        {
            var priceEnd = Convert.ToInt32(endPrice);
            products = products.Where(k => k.CurrentPrice <= priceEnd).ToList();
        }
    }

    List<Product> lpd2 = products.Take(3).ToList();
    string exp = "";
    foreach (Product p in lpd2)
        exp += p.Name + ", " + p.Code;

    if (products.Count > 0)
    {
        ViewBag.Title = exp;
        Category catt = null;
        string catname = "";
        if (products[0].CategoryId != null)
        {
            Int32 cidd = Convert.ToInt32(products[0].CategoryId);
            catt = context.Categories.Where(k => k.Id == cidd).FirstOrDefault();
            catname = catt.Name;
        }
        ViewBag.Description = catname + "/" + products[0].Name;
        City city = null;
        string cityName = "";
        if (products[0].City != null)
        {
            Int32 cityidd = Convert.ToInt32(products[0].City);
            city = context.Cities.FirstOrDefault(k => k.Id == cityidd);
            cityName = city.Name;
        }

        if (city != null)
            cityName = city.Name + ",";
        ViewBag.Keywords = cityName + catname + "," + exp;
    }

    Session["BeforeProducts"] = products;
    List<Product> prods = products.OrderByDescending(m => m.Id).ToList();

    return View(new HomeViewModel
    {
        listpG = context.ProductGroups.ToList(),
        listCatG = context.Categories.ToList(),
        listMarks = context.Marks.ToList(),
        currencies = context.Currencies.ToList(),
        products = prods,
        cities = context.Cities.ToList(),
        listFuelTypes = context.FuelTypes.ToList(),
        listCaseTypes = context.CaseTypes.ToList(),
        listGearTypes = context.GearTypes.ToList(),
        ViewType = "VhicleProduct"
    });
}

请看我讨厌这种代码

Answer 1

可以使用PredicateBuilder来形成复杂的查询。

喜欢,

        var predicate = PredicateBuilder.False<Product>();

        if (param1 != null && param1 == 1 && param2 != null && param2 == 2 && param3 != null && paaram3 == 3)
        {
            predicate = predicate.Or(p => p.param1 == param1 && p.param2 == param1 = 2 && p.param3 == param3);
        }
        else if (param1 != null && param1 == 1 && param2 != null && param2 == 2)
        {
          ---------
        }
        else if (param1 != null && param1 == 1)
          ---------

最后，

        dbContextContext.Products.AsExpandable().Where(predicate);

还有一个通用PredicateBuilder也可用，它不需要LinqPad和AsExpandable()扩展。