基于子项过滤父(标题)记录 [英] Filtering Parent (Header) Records Based on Child

问题描述

我有两个桌子.

• 一个存储订单标头信息(例如订单号，送货地址，客户，销售人员，电话号码)的人
• 另一个存储有诸如股票代码，订购数量之类的详细信息

它们以一对多关系连接在一起，以便订单抬头到订单详细信息.我想允许用户根据子项进行搜索(即查找其中包含产品x的所有订单).我看了看长度，可以找到相反的方向(过滤子 基于大师)，但对此却没有运气.

They are joined on a one to many relationship for order header to order details. I want to allow the user to search based on the child (i.e. find all orders that have product x in them). I have looked at length and can find the opposite (filtering child based on master) but no luck on this one.

我确定这必须可用吗?

谢谢

詹姆斯

推荐答案

您需要创建一个自定义查询，并在预处理事件中添加代码以进行过滤.

You need to create a custom query and add code in the pre-process event to do the filtering.

下面是一个示例，其中包含一些可选参数，可按部分产品名称和产品代码进行过滤.

Here is an example with a couple of optional parameters to filter by partial product name and product code.

OrderHeaders<-=> OrderLines< =->产品

OrderHeaders <-=> OrderLines <=-> Products

在这种情况下，示例事件代码为:

And the sample event code in this case is:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.LightSwitch;
using Microsoft.LightSwitch.Security.Server;
namespace LightSwitchApplication
{
    public partial class ApplicationDataService
    {
        partial void OrdersByProduct_PreprocessQuery(string ProductName, string ProductCode, ref IQueryable<OrderHeader> query)
        {
            if (!String.IsNullOrEmpty(ProductName))
            {
                if (String.IsNullOrEmpty(ProductCode))
                {
                    query = from order in query where order.OrderLines.Any(ol => ol.Product.Name.Contains(ProductName)) select order;
                }
                else
                {
                    query = from order in query where order.OrderLines.Any(ol => ol.Product.Name.Contains(ProductName) && ol.Product.ProductCode.Contains(ProductCode)) select order;
                }
            }
            else if (!String.IsNullOrEmpty(ProductCode))
            {
                query = from order in query where order.OrderLines.Any(ol => ol.Product.ProductCode.Contains(ProductCode)) select order;
            }
        }
    }
}

如果是VB，则使用代码转换器将C#转换为VB.

If it is VB then use a code converter to translate C# to VB.

欢呼

戴夫

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