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Complex nested Array trying to find if an object is null c# asp.net

I am using an api for a shopping cart that has some complex json (very complicated to me) data structured like in my screenshot below. In this scenario in my code I am trying to fix an error which I am going to explain by illustrating the data and how its structured as I am very new to JSON and arrays.
This is from the Visual Studio json reader of the data that belongs to an order placed by a customer. This item at the index of [0] has a customFields which has a value.
When a customer completes a purchase, some items they bought can have custom fields, like the size of a shirt (Large) or (Medium) or (Small) etc... In the JSON these customFields have a value which in this case is the size of the shirt for me to display at the thank you page so the customer knows what size he bought. Essentially I am trying to have the data ready to pass to the thank you page view.
When I am calling for these items in my controller, the code only works if ALL the items that were purchased have a customFields. If the customer buys something like a coffee mug that has NO custom fields, then the application breaks because I guess my code is only accounting for items that actually have customFields.
This is the code that I have so far that only works when ALL items that were purchased have a custom field. This is inside my controller.
public ActionResult Thankyou(string token)
{
int itemsCountAddedToCart = (int)obj["items"].Count();
var items = obj["items"].Select(o =>
new Item
{
name = o["name"].ToString(),
quantity = int.Parse(o["quantity"].ToString()),
price = double.Parse(o["price"].ToString()),
image = o["image"].ToString(),
url = o["url"].ToString(),
//This customFields is what works, but only if all items had custom fields.
customFields = o["customFields"][0]["value"].ToString(),
});
thankYouViewModel.OrderItems = items;
}
//ThankYou View Model that loads hold the data to be able to show in the view.
public class ThankYouViewModel
{
public IEnumerable<Item> OrderItems { get; set; }
}
public class Item
{
public string name { get; set; }
public double price { get; set; }
public int quantity { get; set; }
public string image { get; set; }
public string url { get; set; }
//customFields
public string customFields { get; set; }
}
So that code above works, but breaks when I have items that do not have customFields. This is the error that I get:
System.ArgumentOutOfRangeException: 'Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index'
So how should my code look where its currently breaking so that it can account for situations where one of the items from the JSON does not have a customFields attribute? I am very stuck and have tried to add some conditional statements but did not work because I am dealing with some complex json I do not understand very well yet.

If you want to forget the possibility of more than one element in the customFields array, and only cast the first element value to a string, then use this:
customFields = (o["customFields"] == null || o["customFields"].Count() == 0)?null:o["customFields"][0]["value"].ToString(),

With customFields = o["customFields"][0]["value"].ToString(), you directly receive the value from the customFields Array. If there is no Array in your case then there is nothing to get.
I would recommend you to check if your customFields exists:
var item = new Item ();
item.name = o["name"].ToString();
item.quantity = int.Parse(o["quantity"].ToString());
item.price = double.Parse(o["price"].ToString());
item.image = o["image"].ToString();
item.url = o["image"].ToString();
if(o["customFields"] != null)
{
item.customFields = o["customFields"][0]["value"].ToString();
}

Using Contains() in a Realm query

Let's say we have a realm results taken with
RealmDb.All<Entry>();
Then I want to do some search over those results using not yet supported techniques, like StartsWith on a function return or on a property which is not mapped in realm etc, so I get a subset
IEnumerable<Entry> subset = bgHaystack;
var results = subset.Where(entry => entry.Content.ToLower().StartsWith(needle));
To get somehow these as part of RealmResults, I extract the entry ids like this:
List<int> Ids = new List<int>();
foreach (Entry entry in entries)
{
Ids.Add(entry.Id);
}
return Ids;
and finally I want to return a subset of RealmResults (not IEnumerable) of only those Entries that contain those ids, how can I do that? IDE says the Contains method is not supported.
Can I use some kind of predicate or a comparer for that?
Entry is my model class
using System.ComponentModel.DataAnnotations.Schema;
using Realms;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System;
namespace Data.Models
{
[Table("entry")]
public class Entry : RealmObject
{
public class EntryType
{
public const byte Word = 1;
public const byte Phrase = 2;
public const byte Text = 3;
};
[Key]
[PrimaryKey]
[Column("entry_id")]
public int Id { get; set; }
[Column("user_id")]
public int UserId { get; set; }
[Column("source_id")]
public int SourceId { get; set; }
[Indexed]
[Column("type")]
public byte Type { get; set; }
[Column("rate")]
public int Rate { get; set; }
[Column("created_at")]
public string CreatedAt { get; set; }
[Column("updated_at")]
public string UpdatedAt { get; set; }
[NotMapped]
public Phrase Phrase { get; set; }
[NotMapped]
public Word Word { get; set; }
[NotMapped]
public Text Text { get; set; }
[NotMapped]
public IList<Translation> Translations { get; }
[NotMapped]
public string Content
{
get {
switch (Type)
{
case EntryType.Phrase:
return Phrase?.Content;
case EntryType.Word:
return Word?.Content;
case EntryType.Text:
return Text?.Content;
}
return "";
}
}
}
}

According to the documentation, Realm .NET supports LINQ, so that's promising. In your specific example, you indicate that StartsWith isn't supported, but I see that on the above page, specifically here.
Now, your example makes clear that Entry is a RealmObject, so it's not clear where you'd possibly get a RealmResult from (nor does their documentation on that page mention a RealmResult). Specifically, the home page indicates that you're really only going to ever work with Realm, RealmObject and Transaction, so I'm going to just assume that you meant that you'll need a resulting RealmObject per their examples.
The way you presently have your data object set up, you're rather stuck calling it like you are (though if I could make a recommendation to simplify it a little bit:
var entries = RealmDb.All<Entry>().ToList();
var results = entries.Where(entry => entry.Content.ToLower().StartsWith(needle));
var ids = results.Select(a => a.Id).ToList();
Now, your big issue with just combining the filter predicate in line 2 with the end of line 1: Content itself is marked with a [NotMapped] attribute. Per the documentation again:
As a general rule, you can only create predicates with conditions that
rely on data in Realm. Imagine a class
class Person : RealmObject
{
// Persisted properties
public string FirstName { get; set; }
public string LastName { get; set; }
// Non-persisted property
public string FullName => FirstName + " " + LastName;
}
Given this class, you can create queries with conditions that apply to
the FirstName and LastName properties but not to the FullName
property. Likewise, properties with the [Ignored] attribute cannot be
used.
Because you're using [NotMapped], I've got to believe that's going to behave similarly to [Ignored] and further, because it's just a computed value, it's not something that Realm is going to be able to process as part of the query - it simply doesn't know it because you didn't map it to the information Realm is storing. Rather, you'll have to compute the Content property when you've actually got the instances of your Entry objects to enumerate through.
Similarly, I expect you'll have issues pulling values from Phrase, Word and Text since they're also not mapped, and thus not stored in the record within Realm (unless you're populating those in code you didn't post before executing your Where filter).
As such, you might instead consider storing separate records as a PhraseEntry, WordEntry, and TextEntry so you can indeed perform exactly that filter and execute it on Realm. What if you instead used the following?
public class Entry : RealmObject
{
[Key]
[PrimaryKey]
[Column("entry_id")]
public int Id { get; set; }
[Column("user_id")]
public int UserId { get; set; }
[Column("source_id")]
public int SourceId { get; set; }
[Column("rate")]
public int Rate { get; set; }
[Column("created_at")]
public string CreatedAt { get; set; }
[Column("updated_at")]
public string UpdatedAt { get; set; }
[Column("content")]
public string Content { get; set; }
[NotMapped]
public IList<Translation> Translations { get; }
}
[Table("wordEntry")]
public class WordEntry : Entry
{
}
[Table("phraseEntry")]
public class PhraseEntry : Entry
{
}
[Table("textEntry")]
public class TextEntry : Entry
{
}
And now, you can offload the filtering to Realm:
var wordEntries = RealmDb.All<WordEntry>.Where(entry =>
entry.Content.StartsWith(needle, StringComparison.OrdinalIgnoreCase)).ToList();
var phraseEntries = RealmDb.All<PhraseEntry>.Where(entry => entry.Content.StartsWith(needle, StringComparison.OrdinalIgnoreCase)).ToList();
var textEntries = RealmDb.All<TextEntry>.Where(entry => entry.Content.StartsWith(needle, StringComparison.OrdinalIgnoreCase)).ToList();
var entries = new List<Entry>();
entries.AddRange(wordEntries);
entries.AddRange(phraseEntries);
entries.AddRange(textEntries);
var ids = entries.Select(entry => entry.Id).ToList();
It's not quite as brief as storing it all in one table, but I'm not immediately seeing any Realm documentation that indicates support for executing the same query against multiple tables simultaneously, so at least this would allow you to leave the filtering to the database and work against a more limited subset of values locally.
Finally, so we have all that and I missed your final question up top. You indicate that you want to return a subset of your entries based on some collection of ids you create. In the logic you provide, you're retrieving all the Id properties in all your results, so there's really no further subset to pull.
That said, let's assume you have a separate list of ids that for whatever complicated reason, you were only able to derive after retrieving the list of Entry types from above (themselves all PhraseEntry, WordEntry or TextEntry objects).
At this point, since you've already pulled all the values from Realm and have them locally, just execute another Where statement against them. Because a List implements IEnumerable, you can thus execute the LINQ locally without any of the Realm restrictions:
var myLimitedIdSet = new List<int>()
{
10, 15, 20, 25 //Really complicated logic to narrow these down locally
};
var resultingEntries = entries.Where(entry => myLimitedIdSet.Contains(entry.Id)).ToList();
And you're set. You'll have only those entries that match the IDs listed in myLimitedIdSet.
Edit to address comment
You see this error because of the detail provided at the top of this page in the documentation. Specifically (and adapting to your code):
The first statement gives you a new instance of Entry of a class that implements IQueryable... This is standard LINQ implementation - you get an object representing the query. The query doesn't do anything until you made a further call that needs to iterate or count the results.
Your error is then derived by taking the result from RealmDb.All<Entry>() and trying to cast it to an IEnumerable<Entry> to operate against it as though you have local data. Until you call ToList() onRealmDb.All` you simply have a LINQ representation of what the call will be, not the data itself. As such, when you further refine your results with a Where statement, you're actually adding that to a narrowed version of the IQueryable statement, which will also fail because you lack the appropriate mapping in the Realm dataset.
To skip the optimization I provided above, the following should resolve your issue here:
var bgHaystack = realm.All<Entry>().ToList(); //Now you have local data
var results = bgHaystack.Where(entry => entry.Content.ToLower().StartsWith(needle));
Unfortunately, given your provided code, I don't expect that you'll see any matches here unless needle is an empty string. Not only is your Content property not part of the Realm data and you thus cannot filter on it within Realm, but neither are your Phrase, Word or Text properties mapped either. As a result, you will only ever see an empty string when getting your Content value.
You can further refine the results variable above to yield only those instances with a provided ID as you see fit with normal LINQ (as again, you'll have pulled the data from Realm in the first line).
var limitedIds = new List<int>{10, 20, 30};
var resultsLimitedById = results.Select(a => limitedIds.Contains(a.Id)).ToList();
I've updated my examples above to reflect the use of ToList() in the appropriate places as well.

Change the type of one of the objects property and sort it using LINQ

I want to sort the List where the objects properties are of string type.
One of the property is a time of string type, and when i try to sort it sorts like below.
1:12, 13:24, 19:56, 2:15, 26:34, 8:42.
Here the sorting is happening on string basis.
Now i want to convert that sting to double (1.12, 13.24, 19.56, 2.15, 26.34, 8.42) and sort it. Then populate the data by replacing the '.' with ':'.
I tried some thing like below, but still the sorting is happening on string basis.
public class Model
{
public string Duration { get; set; }
public string Dose { get; set; }
}
List<Model> lsModelData = new List<Model>();
//Added some model objects here
// query for sorting the lsModelData by time.
var sortedList = lsModelData.OrderBy(a => Convert.ToDouble(a.Duration.Replace(":", ".")));
I am trying to replace the time ":" with "." and then convert that to double to perform the sort operation.
Can any one please correct this statement to work this sorting properly.

If you want to sort data according to duration try this. its tested surely works for you.
public class Models
{
public string Duration { get; set; }
public string Dose { get; set; }
}
List<Models> lstModels = new List<Models>();
lstModels.Add(new Models { Duration = "101:12" });
lstModels.Add(new Models { Duration = "13:24" });
lstModels.Add(new Models { Duration = "19:56" });
List<Models> sortedList = (from models in lstModels
select new Models
{
Dose = models.Dose,
Duration = models.Duration.Replace(':','.')})
.ToList()
.OrderBy(x=>Convert.ToDouble(x.Duration))
.ToList();

I'm not sure what you really want, but if you want to return only the duration, then select it after sort
var sortedList = lsModelData.OrderBy(a => Convert.ToDouble(a.Duration.Replace(":", "."))).Select(a=> a.Duration).ToList();
or
var sortedList = lsModelData..Select(a=> a.Duration).OrderBy(a => Convert.ToDouble(a.Replace(":", "."))).ToList();

In cases like this it works best to order by length and then by content:
var sortedList = lsModelData.OrderBy(a => a.Duration.Length)
.ThenBy(a => a.Duration)
Converting database data before sorting (or filtering) always makes queries inefficient because indexes can't be used anymore.

Getting error at time of binding ListBoxFor control in MVC4

When I am changing the "model => model.id" to "model => model.Supplierid" i am getting below error
"The parameter 'expression' must evaluate to an IEnumerable when
multiple selection is allowed."
please have look on below code
// this my model class
public class clslistbox{
public int id { get; set; }
public int Supplierid { get; set; }
public List<SuppDocuments> lstDocImgs { get; set; }
public class SuppDocuments
{
public string Title { get; set; }
public int documentid { get; set; }
}
public List<SuppDocuments> listDocImages()
{
List<SuppDocuments> _lst = new List<SuppDocuments>();
SuppDocuments _supp = new SuppDocuments();
_supp.Title = "title";
_supp.documentid = 1;
_lst.Add(_supp);
return _lst;
}
}
// this my controller
[HttpGet]
public ActionResult AddEditSupplier(int id)
{
clslistbox _lst = new clslistbox();
_lst.lstDocImgs= _lst.listDocImages();
return View(_lst);
}
// this is view where i am binding listboxfor
#model clslistbox
#using (Html.BeginForm("AddEditSupplier", "Admin", FormMethod.Post))
{
#Html.ListBoxFor(model => model.id, new SelectList(Model.lstDocImgs, "documentid", "title"))
}
Can anyone see the reason for it?

I think the changing of the property in the expression here is a red-herring - it won't work in either case.
Update
However, see at the end of my answer for some probably needlessly detailed exposition on why you didn't get an error first-time round.
End Update
You're using ListBoxFor - which is used to provide users with multiple selection capabilities - but you're trying to bind that to an int property - which cannot support multiple selection. (It needs to be an IEnumerable<T> at least to be able to bind a list box to it by default in MVC)
I think you mean to be using DropDownListFor - i.e. to display a list of items from which only one can be selected?
If you're actually looking for single-selection semantics in a listbox, that's trickier to do in MVC because it's Html helpers are geared entirely around listboxes being for multiple selection. Someone else on SO has asked a question about how to get a dropdown to look like a list box: How do I create a ListBox in ASP.NET MVC with single selection mode?.
Or you could generate the HTML for such a listbox yourself.
(Update) - Potentially needlessly detailed exposition(!)
The reason you don't get an exception first time round is probably because there was no value for id in ModelState when the HTML was generated. Here's the reflected MVC source (from SelectExtensions.SelectInternal) that's of interest (the GetSelectListWithDefaultValue call at the end is the source of your exception):
object obj =
allowMultiple ? htmlHelper.GetModelStateValue(fullHtmlFieldName, typeof(string[])) :
htmlHelper.GetModelStateValue(fullHtmlFieldName, typeof(string));
if (!flag && obj == null && !string.IsNullOrEmpty(name))
{
obj = htmlHelper.ViewData.Eval(name);
}
if (obj != null)
{
selectList =
SelectExtensions.GetSelectListWithDefaultValue(selectList, obj, allowMultiple);
}
Note first that the control variable allowMultiple is true in your case, because you've called ListBoxFor. selectList is the SelectList you create and pass as the second parameter. One of the things that MVC (unfortunately in some cases) does is to use ModelState to modify the select list you pass when re-displaying a view in order to ensure that values which were set in ModelState via a POST are re-selected when the view is reloaded (this is useful when page validation fails because you won't copy the values to your underlying model from ModelState, but the page should still show those values as being selected).
So as you can see on the first line, the model's current value for the expression/field you pass is fished out of model state; either as a string array or as a string. If that fails (returns null)then it makes another go to execute the expression (or similar) to grab the model value. If it gets a non-null value from there, it calls SelectExtensions.GetSelectListWithDefaultValue.
As I say - what you're trying to do will ultimately not work in either the case of Id or SupplierId (because they would need to be IEnumerable) but I believe this ModelState->Eval process is yielding a null value when you use Id, so the process of getting an 'adjusted' SelectList is skipped - so the exception doesn't get raised. The same is not true when you use SupplierId because I'll wager that there's either a value in ModelState at that point, or the ViewData.Eval successfully gets an integer value.
Not throwing an exception is not the same as working!.
End update

Try changing your property from int to int[]
public class SuppDocuments
{
public string Title { get; set; }
public int documentid { get; set; }
}
Assuming above is the class used for binding the model , try changing the documentid property as below
public class SuppDocuments
{
public string Title { get; set; }
public int[] documentid { get; set; }
}

IEnumerable to IList casting possibilites

I am trying to ensure that my fields and page options are valid and on one page i want to check and see if an item is selected or not - which a selection is required to save.
I have the following:
in ViewEntry: public IList<Guid> Parties { get; set; }
in my ViewModel: public IEnumerable<Guid> PartiesSelected { get; set; }
Here is my ensure valid code:
public void EnsureValid(VisitEntry visitEntry)
{
var errors = new RulesException<VisitActivityEntryDTO>();
if(visitEntry.Parties == null )
errors.ErrorForModel(string.Format("No {0} selected", Kids.Resources.Entities.Party.EntityNamePlural));
if (errors.Errors.Any())
throw errors;
}
and in my controller my Get Edit method when loading the page I have:
viewModel.PartiesSelected = visitEntry.VisitEntryParties.Select(v=>v.PartyId);
Is it possible in any way that i could possibly have:
viewEntry.Parties = viewModel.PartiesSelected
or
viewEntry.Parties = visitEntry.VisitEntryParties.Select(v=>v.PartyId);
I mainly want to have the selected party to show up in the list of Parties for the ViewEntry so when i validate.

viewEntry.Parties = viewModel.PartiesSelected.ToList()