如何对从 LINQ 查询从 SQL Server 返回的相同结果集的结果进行分组和联接？

Question

I have the following data structure

In a Customer report, there are multiple orders from different clients and each order there are one to many items. When I execute my stored procedure, the data it returns in the result set has the above structure (note: there are duplicates in the query because one order has many items). There is a column called ReportSequence this is the order of appearance of the record on the report.

public class CustomerReport
{
    public int CustomerId { get; set; }     //maps to the CustomerId column in SQL Query result
    public string FirstName { get; set; }   //maps to the FName column
    public string LastName { get; set; }    //maps to the LName column
    public DateTime? ReportDate { get; set; }  //Generated at object creation
    public List<SaleOrder> SalesOrders { get; set; }  //see SaleOrder class

    public CustomerReport()
    {
        SalesOrders = new List<SaleOrder>();
    }
}

public class SaleOrder
{
    public int? SaleOrderId { get; set; }       //maps to the SalesOrderId column in sql query result 
    public string SaleOrderNumber { get; set; }  // maps to SalesOrderNumber column

    public List<SalesOrderItem> OrderItems { get; set; }  //see SalesOrderItem class
    public int? SaleOrderTypeId { get; set; }     //maps to SalesOrderTypeId column
    public int? ReportSequenceNo { get; set; } //the sequence order 1,2,3... how each Sales Order appears on the report

    public SaleOrder()
    {
        OrderItems = new List<SalesOrderItem>();
    }
}

public class SalesOrderItem
{
    public int? ItemTypeId { get; set; }  //maps to ItemTypeId column in sql query result 
    public int? ItemId { get; set; }      // maps to ItemId column
    public string ItemName { get; set; }  //maps to ItemName column
}

Using the result returned by query execution (show on Excel screenshot), I need to generate the following JSON structure:

    {
        "CustomerId" : "10001",
        "FirstName" : "Nicholas",
        "LastName" : "Cage",
        "ReportDate" : "toays date",
        SalesOrders: [
            { 
                SaleOrderId : 6 , 
                SaleOrderNumber : "EB100X100" ,
                SaleOrderTypeId : 102, 
                ReportSequenceNo : 1, 
                SalesOrderItems : [
                    { ItemTypeId : NULL, ItemId :  NULL, ItemName : Null }
                ]  
            },
            ...
        ]
    }

The method I followed is:

First I have tried to build two sets of data from one set

1. The original result set was grouped by SalesOrderId
2. The above was joined with the original

But joining failed ... could not join them....

How do I build this JSON structure from Linq using above resultset and classes?

Answer 1

all right, what you need here is the proper grouping of the source data.

allRecords.GroupBy(a=>a.CustomerId).Select(b=> new CustomerReport(b.Key){ 
SalesOrders = b.Values.GroupBy(c=>c.SaleOrderId).Select(d=> new SaleOrder(d.Key).........)}

It is not complete but I hope gives you a hint