LINQ的综合运用

最新推荐文章于 2025-07-13 12:47:50 发布

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本文介绍了一个使用LINQ进行复杂数据查询和排序的例子，包括如何根据产品功能和包装筛选供应商信息，并根据不同排序方式进行结果排序。

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        var v = from pro in f.Product
                from sup in f.SupplyInfo
                from com in f.Company
                where pro.UID == sup.ProductUID
                && com.UID == sup.CompanyUID
                && pro.FunctionUID.ToString().IndexOf(lstFunction.SelectedValue.Trim()) >= 0 //等同于 like '%XXX%'
                && pro.PackageUID.ToString().IndexOf(lstPackage.SelectedValue.Trim()) >= 0
                select new
                {
                    UID = sup.UID,
                    CompanyName = com.CompanyName,
                    ProductName = pro.ProductName,
                    Price = sup.Price,
                    Stock = sup.Stock,
                    TodayCount = ( from tom in f.SupplyInfo2
                                where tom.SupplyInfoUID == sup.UID
                                && tom.TomatoTime.Date == DateTime.Now.Date
                                select tom).Count(),

                    SumCount = (from tom in f.SupplyInfo2
                            where tom.SupplyInfoUID == sup.UID
                            select tom).Count()
                };

        if (ddlOrder.SelectedItem.Text.Trim() == "价格从低到高" || ddlOrder.SelectedItem.Text.Trim() == "默认排序")
        {
            var v2 = v.OrderBy(u => u.价格);
            GridView1.DataKeyNames = new string[] { "UID" };
            GridView1.DataSource = v2;
        }
        if (ddlOrder.SelectedItem.Text.Trim() == "价格从高到低")
        {
            var v2 = v.OrderByDescending(u => u.价格);
            GridView1.DataKeyNames = new string[]{"UID"};
            GridView1.DataSource = v2;
        }

        GridView1.DataBind();