C# add anonymous list to typed list

Question

I am a little new to C#, sorry if the question is rudimentary.

I have an anonymous list as result of the following:

var Totals = model.Payments.GroupBy(pm => pm.PaymentType)
             .Select(t => new
               {
                    PaymentType = t.Key,
                    Amount = t.Sum(pm => pm.Amount)
               });

Returns Totals as anonymous list with two entries.

Cash 10000.00

EFT 8000.00

Now I need to add this list to a typed list in my viewmodel. The typed list looks like this

public class PaymentExportViewModel
{
    public List<PaymentReportViewModel> Payments { get; set; }
    public List<PaymentSubTotals> Subs { get; set; }
    public DateTime FromDate { get; set; }
    public DateTime ToDate { get; set; }
    public String VenueName { get; set;}
    public PaymentExportViewModel()
    {
        Payments = new List<PaymentReportViewModel>();
        Subs = new List<PaymentSubTotals>();
    }
}

public class PaymentSubTotals
{
    public string Type { get; set; }
    public decimal Amount { get; set; }
}

So since I need to "convert" to typed I do this

PaymentSubTotals subs = new PaymentSubTotals();
foreach (var t in Totals)
{
    subs.Type = t.PaymentType;
    subs.Amount = t.Amount;
    model.Subs.Add(subs); 
}

The result is that model.subs now contains 2 entries but both are the same (last entry in my loop) EFT 8000.00 EFT 8000.00

What am I missing in the model.Subs.Add ? Or somewhere else ?

why project it to an anonymous type to begin with when you can just project it to a strongly typed class — Steve's a D
– Steve's a D, Commented Feb 8, 2017 at 15:59

Maksim Simkin · Accepted Answer · 2017-02-08 15:53:57Z

2

Move declation of subs inside of foreach loop:

foreach (var t in Totals)
{
    PaymentSubTotals subs = new PaymentSubTotals();
    subs.Type = t.PaymentType;
    subs.Amount = t.Amount;
    model.Subs.Add(subs); 
}

In your code you change the same sub object every time, so you do have only the data of the last t variable, repeated.

answered Feb 8, 2017 at 15:53

Maksim Simkin

9,7084 gold badges38 silver badges52 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Gustavo Zanardini Over a year ago

That is because in C#, when you add an item to a list it is passed by reference, not a copy, right? That's why when you modify subs, it modifies the item in the list?

Maksim Simkin Over a year ago

@GustavoZanardini yes, it's a reference type - class, so in the list are just n references to the same object.

JohannC Over a year ago

Of course, I feel a little silly now. Hopefully it can help someone else.

Sherlock · Accepted Answer · 2017-02-08 16:11:57Z

2

Why don't you Select into your PaymentSubTotals instead.

var Totals = model.Payments.GroupBy(pm => pm.PaymentType)
.Select(t => new PaymentSubTotals
{
 Type = t.Key,
 Amount = t.Sum(pm => pm.Amount)
});

answered Feb 8, 2017 at 16:11

Sherlock

1,0308 silver badges19 bronze badges

Comments

Kevin Mills · Accepted Answer · 2017-02-08 16:02:44Z

1

I would recommend the following method to add a new PaymentSubTotals object on each loop.

foreach (var t in Totals)
{
    model.Subs.Add(new PaymentSubTotals {
        Type = t.PaymentType;
        Amount = t.Amount;
    }); 
}

answered Feb 8, 2017 at 16:02

Kevin Mills

40710 silver badges17 bronze badges

Collectives™ on Stack Overflow

C# add anonymous list to typed list

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related