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Add values to a list inside a list Linq

I am having a class like this.
public class CameraModel
{
public int JobId { get; set; }
public int ViewId { get; set; }
public Guid ViewGuid { get; set; }
public string Name { get; set; }
public int ViewNum { get; set; }
public int LayoutID { get; set; }
public List<CameraViewItemModel> CameraViewItems { get; set; }
}
The CameraViewItemModel class is like this:
public class CameraViewItemModel
{
public int JobID { get; set; }
public Guid ViewGuid { get; set; }
public int ViewID { get; set; }
public int CamNum { get; set; }
public Guid ChannelGuid { get; set; }
public string Name { get; set; }
public ActionType Action { get; set; }
}
Now, I am assigning the list of CameraViewItemModel like this:
// get all the cameramodel's
cameraModels = _unitOfWork.Context.CameraViews.Where(m => m.JobId == siteId)
.Select(m => new CameraModel
{
JobId = m.JobId,
ViewId = m.ViewId,
ViewGuid = m.ViewGuid,
Name = m.Name,
ViewNum = m.ViewNum,
LayoutID = m.LayoutId
}).ToList();
// get all the cameraviewitemmodels
cameraViewItemModels =
(from cameraView in _unitOfWork.Repository<CameraViews>().Get(x => x.JobId == siteId).Result
join cameraViewItem in _unitOfWork.Repository<CameraViewItems>().Get(x => x.JobId == siteId)
.Result on cameraView.ViewId equals cameraViewItem.ViewId into CameraViewItemResults
from cameraViewItemResult in CameraViewItemResults.DefaultIfEmpty()
join cameraChannel in _unitOfWork.Repository<CameraChannels>().Get(x => x.JobId == siteId)
.Result on (cameraViewItemResult == null ? new Guid() : cameraViewItemResult.ChannelGuid) equals cameraChannel.ChannelGuid into CameraChannelResults
from cameraChannelResult in CameraChannelResults.DefaultIfEmpty()
select new CameraViewItemModel
{
JobID = cameraView.JobId,
ViewID = cameraView.ViewId,
ViewGuid = cameraView.ViewGuid,
CamNum = cameraViewItemResult.CamNum,
ChannelGuid = cameraChannelResult.ChannelGuid,
Name = cameraChannelResult.Name
}).ToList();
// then do a 'join' on JobId, ViewId and ViewGuid and assign the list of cameraviewitemmodels to cameraModels.
foreach (var cameraModel in cameraModels)
{
cameraModel.CameraViewItems = (from cameraViewItem in cameraViewItemModels
where cameraModel.JobId == cameraViewItem.JobID
&& cameraModel.ViewId == cameraViewItem.ViewID
&& cameraModel.ViewGuid == cameraViewItem.ViewGuid
select cameraViewItem).ToList();
}
return cameraModels;
There are three tables in database:
CameraViews, CameraViewItems, CameraChannels.
CameraViews is the main table. It is left joined with CameraViewItems and CameraChannels to get the desired result. There may not be any data in CameraViewItems and CameraChannels for a corresponding CameraView.
Is it possible to assign the list of CameraViewItemModels to CameraModels in a single linq statement.

Here is a simple way to add values to a sub list, dunno if this is what you mean. You can keep selecting sub lists if that is necessary.
var parent_lst = new List<List<string>>(); // Root/parent list that contains the other lists
var sub_lst = new List<string>(); // Sub list with values
var selected_parent_lst = parent_lst[0]; // Here I select sub list, in this case by list index
selected_parent_lst.Add("My new value"); // And here I add the new value

Assign 0 to Id to Null value

Can someone help me to assign the value of 0 if no records found for this Linq query. Currently I am returning null, But i need to assign 0 if it is null.
//Linq Query
var ideasQuery = from b in db.StarLive_StarIBox_Ideas.Where(b => b.UserId == userid)
select new IdeasDTO()
{
IdeaId = b.IdeaId,
Idea = b.Idea,
UserName = b.StarLive_Sys_Users.cLogName,
DatePosted = b.DatePosted.ToString(),
Problem = b.StarLive_StarIBox_Problems.Problems,
Department = b.StarLive_Sys_Users.nDeptID.ToString(),
LikeId=b.StarLive_StarIBox_Likes.Where
(l=>l.IdeaId==b.IdeaId && l.LikedBy==b.UserId).FirstOrDefault().LikeID
};
//DTO Class
public class IdeasDTO
{
[DataMember]
public int IdeaId { get; set; }
[DataMember]
public string UserName { get; set; }
[DataMember]
public string Idea { get; set; }
[DataMember]
public string DatePosted { get; set; }
[DataMember]
public string Problem { get; set; }
[DataMember]
public int Likes { get; set; }
[DataMember]
public bool Liked { get; set; }
[DataMember]
public string Department { get; set; }
[DataMember]
public int? LikeId { get; set; }
}
//Postman Response
{
"IdeaId": 21,
"UserName": "Gowthamb",
"Idea": "This is an Idea",
"DatePosted": "Feb 14 2019 3:19PM",
"Problem": "Problem 1",
"Likes": 0,
"Liked": false,
"Department": "1",
"LikeId": null
}
Please help

Change this:
//Linq Query
var ideasQuery = from b in db.StarLive_StarIBox_Ideas.Where(b => b.UserId == userid)
select new IdeasDTO()
{
IdeaId = b.IdeaId,
Idea = b.Idea,
UserName = b.StarLive_Sys_Users.cLogName,
DatePosted = b.DatePosted.ToString(),
Problem = b.StarLive_StarIBox_Problems.Problems,
Department = b.StarLive_Sys_Users.nDeptID.ToString(),
LikeId=b.StarLive_StarIBox_Likes.Where
(l=>l.IdeaId==b.IdeaId && l.LikedBy==b.UserId).FirstOrDefault().LikeID
};
To this:
//Linq Query
var ideasQuery = from b in db.StarLive_StarIBox_Ideas.Where(b => b.UserId == userid)
select new IdeasDTO()
{
IdeaId = b.IdeaId,
Idea = b.Idea,
UserName = b.StarLive_Sys_Users.cLogName,
DatePosted = b.DatePosted.ToString(),
Problem = b.StarLive_StarIBox_Problems.Problems,
Department = b.StarLive_Sys_Users.nDeptID.ToString(),
LikeId=b.StarLive_StarIBox_Likes.Where
(l=>l.IdeaId==b.IdeaId && l.LikedBy==b.UserId).FirstOrDefault().LikeID ?? 0
};
Explanation:
LikeID is a int? it means that it is nullable.
the ?? operator, means that if the result is null it must assign the value on the right, which will be 0 in this case:
LikeId=b.StarLive_StarIBox_Likes.Where(l=>l.IdeaId==b.IdeaId && l.LikedBy==b.UserId).FirstOrDefault().LikeID ?? 0

You can write something like this
change LikeId=b.StarLive_StarIBox_Likes to LikeId=b.StarLive_StarIBox_Likes == null ? 0 : b.StarLive_StarIBox_Likes

Join with inner list

I have this linq query:
var investorData = from investor in db.Investors
join investorLine in db.InvestorStatementLines
on investor.InvestorID equals investorLine.InvestorID
where investor.UserId == userId
select new InvestorViewModel()
{
InvestorId = investor.InvestorID,
InvestorName = investor.Name,
FundingDate = investor.FundingDate,
DueDate = investor.DueDate,
FundsCommitted = investor.FundsCommitted,
FundsInvested = investor.FundsInvested,
StatementLines =
db.InvestorStatementLines.Where(s => s.InvestorID == investor.InvestorID)
.Select(t => new InvestorStatementLineVM
{
Balance = t.Balance,
Credit = t.Credit,
Debit = t.Debit,
InvestorStatementLineDetails = t.Details,
Date = t.Date
}).ToList()
};
The viewmodel:
public class InvestorViewModel
{
public int InvestorId { get; set; }
public string InvestorName { get; set; }
public DateTime FundingDate { get; set; }
public DateTime? DueDate { get; set; }
public Decimal? FundsCommitted { get; set; }
public Decimal? FundsInvested { get; set; }
public List<InvestorStatementLineVM> StatementLines { get; set; }
}
What is happening is once I'm executing the query I'm getting 125 records, and that's the number of the StatementLines for that investor. So I'm getting 125 same records but I'm expecting one result which will have 125 statement lines in the inner list.
Is this query correct?

This is how you can do that with navigation properties
var investorData = from investor in db.Investors
where investor.UserId == userId
select new InvestorViewModel()
{
InvestorId = investor.InvestorID,
InvestorName = investor.Name,
FundingDate = investor.FundingDate,
DueDate = investor.DueDate,
FundsCommitted = investor.FundsCommitted,
FundsInvested = investor.FundsInvested,
StatementLines = investor.InvestorStatementLines
.Select(t => new InvestorStatementLineVM
{
Balance = t.Balance,
Credit = t.Credit,
Debit = t.Debit,
InvestorStatementLineDetails = t.Details,
Date = t.Date
}).ToList()
};

Use GroupJoin instead of Join: (_join x in y on x.a equals y.a
into z_)
var investorData = from investor in db.Investors
join investorLine in db.InvestorStatementLines
on investor.InvestorID equals investorLine.InvestorID
into investorLine
where investor.UserId == userId
select new InvestorViewModel()
{
InvestorId = investor.InvestorID,
InvestorName = investor.Name,
FundingDate = investor.FundingDate,
DueDate = investor.DueDate,
FundsCommitted = investor.FundsCommitted,
FundsInvested = investor.FundsInvested,
StatementLines = investorLine
.Select(t => new InvestorStatementLineVM
{
Balance = t.Balance,
Credit = t.Credit,
Debit = t.Debit,
InvestorStatementLineDetails = t.Details,
Date = t.Date
}).ToList()
};
Also instead of performing the sub-query just use the data from the join you just performed.
A better option, using entity framework, is using navigation properties and then you do not need to perform a join but you just have
InvestorStatementLines as a property of your investor.
To set the navigation properties:
public class InvestorViewModel
{
public int InvestorId { get; set; }
public string InvestorName { get; set; }
public DateTime FundingDate { get; set; }
public DateTime? DueDate { get; set; }
public Decimal? FundsCommitted { get; set; }
public Decimal? FundsInvested { get; set; }
public virtual ICollection<InvestorStatementLineVM> StatementLines { get; set; }
}
And the query will be as simple as:
var investorData = from investor in db.Investors
where investor.UserId == userId
select new InvestorViewModel()
{
InvestorId = investor.InvestorID,
....
StatementLines = investor.InvestorStatementLines.Select(....)
};

Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>' to 'System.Collections.Generic.List<FirstApp.Model.TeamDetails>

I am getting this error
Cannot implicitly convert type
System.Collections.Generic.List<AnonymousType#1> to
System.Collections.Generic.List<FirstApp.Model.TeamDetails>
What's wrong with my code?
Here is my code
TeamDetails Class
public class TeamDetails
{
[Key]
public int TeamId { get; set; }
public string TeamName { get; set; }
public string Description { get; set; }
public int? UserCount { get; set; }
}
ViewModel
public class ViewTeamList
{
public List<TeamDetails> TeamNext { get; set; }
}
Controller
public ActionResult Next(int dataid)
{
ViewTeamList viewTeamList = new ViewTeamList();
var a = from t in tDbContext.Teams
join u in tDbContext.Users on t.TeamId equals u.TeamId into g
where t.Deleted != true
select new { TeamId= t.TeamId,TeamName = t.TeamName, Description = t.Description, UserId = g.Count() };
var next = a.OrderBy(t1 => t1.TeamId).Where(t1 => t1.TeamId > dataid).FirstOrDefault();
viewTeamList.TeamNext = a.ToList();
return PartialView("_ViewTeamDetails", viewTeamList);
}
I'm not able to assign this value to
viewTeamList.TeamNext = a....;

This constructs an anonymous type instead of TeamDetails
select new { TeamId= t.TeamId,TeamName = t.TeamName, Description = t.Description, UserId = g.Count() }
You should change it to below
select new TeamDetails { TeamId = t.TeamId, TeamName = t.TeamName, Description = t.Description, UserCount = g.Count() }
so a.ToList() would be a List<FirstApp.Model.TeamDetails>

How to join tables only if not empty?

I have following LINQ query:
var LINQFilter = (from Cash in _DataTable_Cash.AsEnumerable()
join CashOpeningsAssignments in _DataTable_CashOpeningsAssignments.AsEnumerable().Where(a => (a.Field<Int32>("cashopeningassignmentstatus_id") == 1 || a.Field<Int32>("cashopeningassignmentstatus_id") == 2))
on Cash.Field<Int32>("cash_id") equals CashOpeningsAssignments.Field<Int32>("cash_id") into into_cashopeningsassignments
from CashOpeningsAssignments in into_cashopeningsassignments.DefaultIfEmpty()
join Users in _DataTable_Users.AsEnumerable()
on CashOpeningsAssignments.Field<Int32>("user_id") equals Users.Field<Int32>("user_id") into into_users
from Users in into_users.DefaultIfEmpty()
select new
{
cash_id = Cash.Field<Int32>("cash_id"),
cellar_name = Cellars.Field<String>("cellar_name"),
cash_name = Cash.Field<String>("cash_name"),
cashstatus_name = CashStatus.Field<String>("cashstatus_name"),
user_name = (Users == null ? "[No Data]" : Users.Field<String>("user_firstname") + (Char)32 + Users.Field<String>("user_lastname")),
cashtransaction_amount = (Cash.Field<Int32>("cashstatus_id") == 2 ? 0.00 : 150.00)
});
I have problems showing the result because this Field returns null: CashOpeningsAssignments.Field<Int32>("user_id") when CashOpeningsAssignments is Empty.
I tried moving the .DefaultIfEmpty() into users but still not working, Any idea how i can solve this?

Answer
Use the overload of DefaultIfEmpty to create an empty item.
E.g.
into_cashopeningsassignments
.DefaultIfEmpty(new CashOpeningsAssignments())
Running Code
The code reflects what you're trying to do, even though I took some liberties with it. For instance, I used List<T> instead of DataTable, because I did not figure out how to use Field<T>(string name) in a DotNetFiddle.
It's live here: https://dotnetfiddle.net/YaAc6D
using System;
using System.Linq;
using System.Collections.Generic;
public class Program
{
public static void Main()
{
var query =
from Cash
in _DataTable_Cash.AsEnumerable()
join CashOpeningsAssignments
in _DataTable_CashOpeningsAssignments.AsEnumerable()
.Where(a =>
(a.cashopeningassignmentstatus_id == 1 ||
a.cashopeningassignmentstatus_id == 2))
on Cash.cash_id
equals CashOpeningsAssignments.cash_id
into into_cashopeningsassignments
from CashOpeningsAssignments
in into_cashopeningsassignments.DefaultIfEmpty(new CashOpeningsAssignments())
join Users
in _DataTable_Users.AsEnumerable()
on CashOpeningsAssignments.user_id
equals Users.user_id
into into_users
from Users
in into_users.DefaultIfEmpty()
select new
{
cash_id = Cash.cash_id,
// cellar_name = Cellars.cellar_name,
cash_name = Cash.cash_name,
// cashstatus_name = CashStatus.cashstatus_name,
user_name = (Users == null ? "[No Data]" : Users.user_firstname + (Char)32 + Users.user_lastname),
cashtransaction_amount = (Cash.cashstatus_id == 2 ? 0.00 : 150.00)
};
foreach(var result in query)
{
Console.WriteLine(result);
}
}
public static List<Cash> _DataTable_Cash =
new List<Cash> { new Cash() };
public static List<Cellars> _DataTable_Cellars =
new List<Cellars> { new Cellars() };
public static List<CashStatus> _DataTable_CashStatus =
new List<CashStatus> { new CashStatus() };
public static List<CashOpeningsAssignments> _DataTable_CashOpeningsAssignments =
new List<CashOpeningsAssignments> { };
public static List<Users> _DataTable_Users =
new List<Users>() { new Users() };
}
public class Cash
{
public int cash_id { get; set; }
public string cash_name { get; set; }
public int cellar_id { get; set; }
public int cashstatus_id { get; set; }
}
public class Cellars
{
public string cellar_name { get; set; }
public int cellar_id { get; set; }
}
public class CashStatus
{
public int cashstatus_id { get; set; }
public string cashstatus_name { get; set; }
}
public class CashOpeningsAssignments
{
public int user_id { get; set; }
public int cash_id { get; set; }
public int cashopeningassignmentstatus_id { get; set; }
}
public class Users
{
public string user_firstname { get; set; }
public string user_lastname { get; set; }
public int user_id { get; set; }
}
See Also
https://msdn.microsoft.com/en-us/library/vstudio/bb355419%28v=vs.100%29.aspx