C# Linq how to use group by to get the desired output - linq

Question

I have the following classes
public class Product
{
public string PNo {get;set;}
public String GCode {get;set;}
public IList<Detail> Details {get;set;}
}
public class Detail{
public string Color {get;set;}
public string Size {get;set;}
}
And i have the data in an array as below
PNO GCode Color Size Amount
12345 GCC A L 1
12345 GCC V M 2
12345 GCC C S 3
12345 GCC D XL 4
12345 GCC E XS 5
How do i get the following output using groupby so that my output could like shown below
Expected output:
{
PNO: 12345,
GCode: GCC,
options:[
{Color:A, Size:L, Amount: 1},
{Color:V, Size:M, Amount: 2},
{Color:C, Size:S, Amount: 3},
{Color:D, Size:XL, Amount: 4},
{Color:E, Size:XS, Amount: 5}
]
}
Thanks

Answer 1

Given the contract you defined. I think below code snippet is OK to generate the JSON you want, I use anonymous object a lot, you can replace with you entity class.
products.GroupBy(product => new
{
product.PNo,
product.GCode
})
.Select(productGroup => new
{
productGroup.Key.PNo,
productGroup.Key.GCode,
options = productGroup.SelectMany(product => product.Details.Select(detail => new
{
detail.Color,
detail.Size,
detail.Amount
}))
});
Hope it helps.

Answer 2

This will get you that expected output:
Query Syntax:
var result = (from item in collection
group item by new { item.PNO, item.GCode } into grouping
select new Product
{
PNo = grouping.Key.PNO,
GCode = grouping.Key.GCode,
Details = grouping.Select(item => new Detail { Color = item.Color, Size = item.Size, Amount = item.Amount }).ToList()
}).ToList();
Method Syntax:
var result = collection.GroupBy(item => new { item.PNO, item.GCode })
.Select(grouping => new Product
{
PNo = grouping.Key.PNO,
GCode = grouping.Key.GCode,
Details = grouping.Select(item => new Detail { Color = item.Color, Size = item.Size, Amount = item.Amount }).ToList()
}).ToList();
Test Data:
List<dynamic> collection = new List<dynamic>()
{
new { PNO = "12345", GCode = "GCC", Color = "A", Size="L", Amount=1 },
new { PNO = "12345", GCode = "GCC", Color = "V", Size="M", Amount=2 },
new { PNO = "12345", GCode = "GCC", Color = "C", Size="S", Amount=3 },
new { PNO = "12345", GCode = "GCC", Color = "D", Size="XL", Amount=4 },
new { PNO = "12345", GCode = "GCC", Color = "E", Size="XS", Amount=5 },
};