Develop Reference

The cast to value type System.Boolean failed because the materialized value is null, result type's generic parameter must use a nullable type

This code was working before but now I've got this error: The cast to value type 'System.Boolean' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type.
public async Task<ActionResult> BankDepositVoucher(BankDepositVoucherSearchViewModel search, int? PageNo)
{
var model = new BankDepositVoucherListViewModel
{
Search = search ?? new BankDepositVoucherSearchViewModel()
};
if (search != null)
{
search.StartDate = search.StartDate.ToStartOfDay();
search.EndDate = search.EndDate.ToEndOfDay();
}
try
{
var Vouchers = DbManager.Invoices.Include(x => x.BankDepositVoucher)
.Where(x => x.Type == InvoiceType.BankDepositVoucher
&& (x.VoucherNumber == search.VoucherNo || search.VoucherNo == null)
&& (x.BankDepositVoucher.SlipNo.Contains(search.SlipNo) || search.SlipNo == null)
&& (x.BankDepositVoucher.ChequeNo.Contains(search.ChequeNo) || search.ChequeNo == null)
&& (x.BankDepositVoucher.Bank.AccountName.Contains(search.BankDetails)
|| search.BankDetails == null)
&& (x.BankDepositVoucher.AccountName.Contains(search.AccountName) || search.AccountName == null)
&& (x.BankDepositVoucher.Narration.Contains(search.Narration) || search.Narration == null)
&& (x.TotalAmount == search.Amount || search.Amount == null)
&& (x.Date >= search.StartDate || search.StartDate == null)
&& (x.Date <= search.EndDate || search.EndDate == null));
//model.Pager = new Pager(await Vouchers.CountAsync(), PageNo, 10);
model.Vouchers = await Vouchers.OrderByDescending(x => x.VoucherNumber)
//.Skip((model.Pager.CurrentPage - 1) * model.Pager.PageSize)
//.Take(model.Pager.PageSize)
.Select(x => new BankDepositVoucherBaseViewModel
{
Id = x.Id,
VoucherNumber = x.VoucherNumber,
AccountName = x.BankDepositVoucher.AccountName,
BankAccountName = x.BankDepositVoucher.Bank.AccountName,
Date = x.Date,
ChequeNo = x.BankDepositVoucher.ChequeNo,
Narration = x.BankDepositVoucher.Narration,
SlipNo = x.BankDepositVoucher.SlipNo,
TotalAmount = x.TotalAmount,
IsCleared = x.BankDepositVoucher.IsCleared
}).ToListAsync();
}
catch (Exception ex)
{
Console.WriteLine("", ex.Message);
}
return PartialView(model);
}
This is the part throwing above mentioned exception
model.Vouchers = await Vouchers.OrderByDescending(x => x.VoucherNumber)
//.Skip((model.Pager.CurrentPage - 1) * model.Pager.PageSize)
//.Take(model.Pager.PageSize)
.Select(x => new BankDepositVoucherBaseViewModel
{
Id = x.Id,
VoucherNumber = x.VoucherNumber,
AccountName = x.BankDepositVoucher.AccountName,
BankAccountName = x.BankDepositVoucher.Bank.AccountName,
Date = x.Date,
ChequeNo = x.BankDepositVoucher.ChequeNo,
Narration = x.BankDepositVoucher.Narration,
SlipNo = x.BankDepositVoucher.SlipNo,
TotalAmount = x.TotalAmount,
IsCleared = x.BankDepositVoucher.IsCleared
}).ToListAsync();

The issue is likely that when populating the view model it cannot deal with the fact that a record may not have a BankDepositVoucher.
For instance:
IsCleared = x.BankDepositVoucher.IsCleared
This should probably be:
IsCleared = x.BankDepositVoucher?.IsCleared ?? false
One other thing to improve performance considerably:
While it may look concise in the code to write statements like this:
.Where(x => x.Type == InvoiceType.BankDepositVoucher
&& (x.VoucherNumber == search.VoucherNo || search.VoucherNo == null)
&& (x.BankDepositVoucher.SlipNo.Contains(search.SlipNo) || search.SlipNo == null)
&& (x.BankDepositVoucher.ChequeNo.Contains(search.ChequeNo) || search.ChequeNo == null)
&& (x.BankDepositVoucher.Bank.AccountName.Contains(search.BankDetails)
|| search.BankDetails == null)
&& (x.BankDepositVoucher.AccountName.Contains(search.AccountName) || search.AccountName == null)
&& (x.BankDepositVoucher.Narration.Contains(search.Narration) || search.Narration == null)
&& (x.TotalAmount == search.Amount || search.Amount == null)
&& (x.Date >= search.StartDate || search.StartDate == null)
&& (x.Date <= search.EndDate || search.EndDate == null));
It is more efficient to write it out as:
.Where(x => x.Type == InvoiceType.BankDepositVoucher);
if(!string.IsNullOrEmpty(search.VoucherNo))
Voucher = Voucher.Where(x => x.VoucherNumber == search.VoucherNo);
if(!string.IsNullOrEmpty(search.SlipNo))
Voucher = Voucher.Where(x => x.BankDepositVoucher.SlipNo.Contains(search.SlipNo))
// etc.
The reason is that in the first case you are generating a much larger SQL statement to be sent to the database, and it is quite easy to "slip up" on conditions if that query is ever edited in the future. (missing parenthesis, etc.) The second example only adds conditions to the query if they are needed, keeping the resulting SQL statement much more compact.

IQueryable with only optional parameters

I currently have the following method:
public List<Order> GetOrders(int profileId, string timeSpan, string workOrd, string partNo, bool includeDeleted)
{
DateTime startDate = DateTime.Now;
DateTime endDate = DateTime.Now;
string[] times = (!string.IsNullOrWhiteSpace(timeSpan)) ? timeSpan.Trim().Split('-') : new string[] { "", "" };
if (!string.IsNullOrWhiteSpace(times[0]) && !string.IsNullOrWhiteSpace(times[0]))
{
startDate = DateTime.Parse(times[0]).Date;
endDate = DateTime.Parse(times[1]).Date;
}
//New Real Query
IQueryable<Order_Travel> otQuery = _context.Order_Travels.Where(x =>
(profileId != 0 || x.Profile.ProfileID == profileId)
&& ((timeSpan == null || timeSpan.Trim() == "") || ((DbFunctions.TruncateTime(x.TimeRecieved) >= startDate)
&& (DbFunctions.TruncateTime(x.TimeRecieved) <= endDate)))
&& ((workOrd == null || workOrd.Trim() == "") || x.Order.WorkOrdNo == workOrd)
&& ((partNo == null ||partNo.Trim() == "") || x.Order.PartNo == partNo)
&& (!includeDeleted || x.Aborted == true));
//The results is now in order_travel. Under here binding them to a list of orders with only the respective orderTravels included.
List<Order> orders = new List<Order>();
List<Order_Travel> ots = otQuery.ToList();
foreach (Order_Travel ot in ots)
{
var OrderInList = orders.FirstOrDefault(X => X == ot.Order);
if (OrderInList == null)
{
orders.Add(ot.Order);
OrderInList = orders.FirstOrDefault(X => X == ot.Order);
OrderInList.OrderTravels.Clear();
OrderInList.OrderTravels.Add(ot);
}
else
{
OrderInList.OrderTravels.Add(ot);
}
}
return orders;
}
What I need it to do, is (as I've attempted) to make a call, finding all Order_Travel objects that match the paramters sent to it. If some (or all) are left blank, it takes everything, regardless of the values.
The code right now, does not return anything, if a blank search is made (a search that does not have any parameters), and I can not see what could be the issue. I have tried debugging it, but with no luck.
Any help would be greatly appreciated!
Thanks!

Filter one option at a time, instead of trying to put everything into a single expression:
IQueryable<T> query = all; // start with everything
if (IsPresent(option1))
{
query = query.Where(t => t.XXX == option1);
}
Example
IQueryable<Order_Travel> otQuery = _context.Order_Travels;
if (profileId != 0)
{
otQuery = otQuery.Where(x => x.Profile.ProfileID == profileId);
}
if (timeSpan != null && timeSpan.Trim() != "")
{
otQuery = otQuery.Where(x => DbFunctions.TruncateTime(x.TimeRecieved) >= startDate &&
DbFunctions.TruncateTime(x.TimeRecieved) <= endDate);
}
You will also find this easier to maintain than one huge expression.

Probably this part is your problem:
(profileId != 0 || x.Profile.ProfileID == profileId)
It should be
(profileId == 0 || x.Profile.ProfileID == profileId)
If your profile ID is 0, it will only find entries with x.Profile.ProfileID being 0. Probably there are no such entries.

randomize Select do not work

I wrote a code that's going to accidentally bring back row of data
I want to 5 row chosen randomly but do not work and return value
Everything was true, but the part that is related to the random return just do not work anymore
public List<tblInvoice> Admin_GetRowsSendProduct(string StartDate, string EndDate, int status = -1, bool Randomize = false)
{
LtSProductDataContext db = new LtSProductDataContext(BLLBase.BLLBase.ConnectionString);
IQueryable<tblInvoice> xxx = db.tblInvoices.Where(p => p.status == true);
DateTime _StartDate = DateTime.MinValue;
DateTime _EndDate = DateTime.MinValue;
if (xConvertor.ToString(StartDate) == "" || xConvertor.ToString(EndDate) == "")
{
if (string.IsNullOrEmpty(StartDate) == false)
_StartDate = BLLBase.xDateTime.DateXorshid2DateMiladi(StartDate.ToString());
if (string.IsNullOrEmpty(EndDate) == false)
{
_EndDate = BLLBase.xDateTime.DateXorshid2DateMiladi(EndDate.ToString());
if (_StartDate == _EndDate) { _EndDate = _StartDate.AddDays(1); }
}
xxx = xxx.Where(p =>
(p.status == true) &&
(_StartDate == DateTime.MinValue || p.Date >= _StartDate) && (_EndDate == DateTime.MinValue || p.Date <= _EndDate));
}
else if (xConvertor.ToString(StartDate) != "" && xConvertor.ToString(EndDate) != "")
{
_StartDate = BLLBase.xDateTime.DateXorshid2DateMiladi(StartDate.ToString());
_EndDate = BLLBase.xDateTime.DateXorshid2DateMiladi(EndDate.ToString());
xxx = xxx.Where(p => p.Date <= _EndDate && p.Date >= _StartDate && p.status == true && p.SendStatus == status);
}
xxx = xxx.Where(p => (status == -1 || p.SendStatus == status) && p.status == true).OrderByDescending(p => p.Date);
if (Randomize)
{
Random rnd = new Random();
xxx = xxx.OrderBy(x => rnd.Next());
//xxx = xxx.OrderBy(o => Guid.NewGuid());
xxx = xxx.Take(3);
return xxx.Where(p => (p.isPostalPayment == null || p.isPostalPayment == false)).ToList();
}
else
{
return xxx.Where(p => (p.isPostalPayment == null || p.isPostalPayment == false)).ToList();
}
//return xxx.Where(p => p.PaymentType != 4).ToList();
}
do not work this section:
xxx = xxx.OrderBy(x => rnd.Next());
or
xxx = xxx.OrderBy(o => Guid.NewGuid());

if (Randomize)
{
List<tblInvoice> _Result = db.tblInvoices.ToList();
var _Temp = xxx.Where(p => (p.isPostalPayment == null || p.isPostalPayment == false)).ToList();
_Result = _Temp.OrderBy(o => Guid.NewGuid()).Take(5).ToList();
return _Result;
}

Include where clause on linq query when param is not null Npgsql

I have following method that registers a contact in database, but before register I check the contact exists or not:
bool RegisterContact(Contact contactInfo) {
bool entityExists =
_dbContext.Contacts.FirstOrDefault(
p => (p.FilesID.Equals(contactInfo.FilesID))
&& (p.EmailAddress ==
(string.IsNullOrEmpty(
contactInfo.EmailAddress)
? p.EmailAddress
: contactInfo.EmailAddress))
&&
(p.DisplayName ==
(string.IsNullOrEmpty(
contactInfo.DisplayName)
? p.DisplayName
: contactInfo.DisplayName)));
}
this query includes the fields that contain value (not null) in search condition (FilesID, EmailAddress, DisplayName)
this technique works fine in MSSQL, today i changed the database manager to PostgreSQL and use Npgsql.
All things work except above linq query, which raises an exception with message of : "could not determine data type of parameter $2"
I was forced to solve it in this way:
bool RegisterContact(Contact contactInfo)
{
Contact entityExists = null;
if (string.IsNullOrEmpty(contactInfo.EmailAddress) &&
(string.IsNullOrEmpty(contactInfo.DisplayName)))
entityExists =
_dbContext.Contacts.FirstOrDefault(
p => p.FilesID.Equals(contactInfo.FilesID));
if (!string.IsNullOrEmpty(contactInfo.EmailAddress) && string.IsNullOrEmpty(contactInfo.DisplayName))
entityExists =
_dbContext.Contacts.FirstOrDefault(
p =>
p.FilesID.Equals(contactInfo.FilesID) &&
p.EmailAddress == contactInfo.EmailAddress);
if (string.IsNullOrEmpty(contactInfo.EmailAddress) && !string.IsNullOrEmpty(contactInfo.DisplayName))
entityExists =
_dbContext.Contacts.FirstOrDefault(
p =>
p.FilesID.Equals(contactInfo.FilesID) &&
p.DisplayName == contactInfo.DisplayName);
if (!string.IsNullOrEmpty(contactInfo.EmailAddress) &&
!string.IsNullOrEmpty(contactInfo.DisplayName))
entityExists =
_dbContext.Contacts.FirstOrDefault(
p =>
p.FilesID.Equals(contactInfo.FilesID) &&
p.EmailAddress == contactInfo.EmailAddress &&
p.DisplayName == contactInfo.DisplayName);
}
Is this Npgsql bug or by design? any known solutions/workarounds for the problem?

I currently have the same cases. I think the problem is the lack of recognition, by NpgSQL, of string.IsNullOrEmpty.
I replaced the test with a check on empty string, always recognizing as not NULL the input parameter.
-- bad
var data = from art in _ctx.Set<Soleo.Model.DLAR>()
from iva in _ctx.Set<Soleo.Model.DLAI>().Where(k => k.DITTA == art.DITTA && k.COD == art.CIVA).DefaultIfEmpty()
from fam in _ctx.Set<Soleo.Model.DLFA>().Where(k => k.DITTA == art.DITTA && k.COD == art.FAM).DefaultIfEmpty()
from mar in _ctx.Set<Soleo.Model.DLMA>().Where(k => k.DITTA == art.DITTA && k.COD == art.MAR).DefaultIfEmpty()
from udm in _ctx.Set<Soleo.Model.DLUM>().Where(k => k.DITTA == art.DITTA && k.COD == art.UM).DefaultIfEmpty()
where art.DITTA == DLAUTH.Config.Current.DITTA && art.COD.Contains(sel_cod) && art.DES.Contains(sel_des)
&& (string.IsNullOrEmpty(sel_fam) || string.Compare(art.FAM, sel_fam, true) == 0)
&& (string.IsNullOrEmpty(sel_mar) || string.Compare(art.MAR, sel_mar, true) == 0)
&& (art.DIS >= sel_dis_da && art.DIS <= sel_dis_a)
select new
{
COD = art.COD,
DES = art.DES,
DES_UDM = udm.DES,
DES_MAR = mar.DES,
DES_FAM = fam.DES,
DES_CIVA = iva.DES,
MAG1 = art.MAG1,
MAG2 = art.MAG2,
DES_DIS = art.DIS == 1 ? "Si" : "No"
};
-- good:
var data = from art in _ctx.Set<Soleo.Model.DLAR>()
from iva in _ctx.Set<Soleo.Model.DLAI>().Where(k => k.DITTA == art.DITTA && k.COD == art.CIVA).DefaultIfEmpty()
from fam in _ctx.Set<Soleo.Model.DLFA>().Where(k => k.DITTA == art.DITTA && k.COD == art.FAM).DefaultIfEmpty()
from mar in _ctx.Set<Soleo.Model.DLMA>().Where(k => k.DITTA == art.DITTA && k.COD == art.MAR).DefaultIfEmpty()
from udm in _ctx.Set<Soleo.Model.DLUM>().Where(k => k.DITTA == art.DITTA && k.COD == art.UM).DefaultIfEmpty()
where art.DITTA == DLAUTH.Config.Current.DITTA && art.COD.Contains(sel_cod) && art.DES.Contains(sel_des)
&& (string.Compare(sel_fam, "", true) == 0 || string.Compare(art.FAM, sel_fam, true) == 0)
&& (string.Compare(sel_mar, "", true) == 0 || string.Compare(art.MAR, sel_mar, true) == 0)
&& (art.DIS >= sel_dis_da && art.DIS <= sel_dis_a)
select new
{
COD = art.COD,
DES = art.DES,
DES_UDM = udm.DES,
DES_MAR = mar.DES,
DES_FAM = fam.DES,
DES_CIVA = iva.DES,
MAG1 = art.MAG1,
MAG2 = art.MAG2,
DES_DIS = art.DIS == 1 ? "Si" : "No"
};
But I do not think this is the solution. I will report the case to NpgSQL.

Return all in List <T> in lambda expression

I'm using lambda expression in LINQ where i have to get all the result when the conditon satisfies if not it should filter.
//Code
List<Dispatch> objDispatch = (List<Dispatch>)Session["Data"];
objDispatch = objDispatch.FindAll(dispatch => dispatch.CustomerTransName == ddlTransporterName.SelectedItem.Text && dispatch.InvoiceDate.Date >= Convert.ToDateTime(FromDate).Date && dispatch.InvoiceDate.Date <= Convert.ToDateTime(ToDate).Date);
In the above code i'm filtering the result set with some conditions in that first condition i need a help.
If the transporter name is 'ALL' it should return all the result set it matches with the Date condition or else it should return according to the TransporterName.
How can i achieve this?

With pure logic.
if(ddlTransporterName.SelectedItem.Text == "ALL") {
//return all
} else {
//Do your filter logic
}
Or, with less repitive code:
objDispatch = objDispatch.FindAll(
dispatch => (ddlTransporterName.SelectedItem.Text == "ALL" || dispatch.CustomerTransName == ddlTransporterName.SelectedItem.Text)
&& dispatch.InvoiceDate.Date >= Convert.ToDateTime(FromDate).Date
&& dispatch.InvoiceDate.Date <= Convert.ToDateTime(ToDate).Date);

string name = ddlTransporterName.SelectedItem.Text;
objDispatch = objDispatch.FindAll(dispatch =>
(name == "ALL" || dispatch.CustomerTransName == name)
&& dispatch.InvoiceDate.Date >= Convert.ToDateTime(FromDate).Date
&& dispatch.InvoiceDate.Date <= Convert.ToDateTime(ToDate).Date);
If transporter name is "ALL" then name OR condition will give true and CustomerTransName will not be checked.

If you want this to be LINQ then you need to actually use a LINQ method e.g. use Where. Also you should do your date conversions once outside if they aren't specific to the row, otherwise they will be converting everytime. Not only that, it makes for more readable code...
var selectedTransporter = ddlTransporterName.SelectedItem.Text;
var fromDate = Convert.ToDateTime(FromDate).Date;
var toDate = Convert.ToDateTime(ToDate).Date;
var query = objDispatch.Where(x => (selectedTransporter == "All" || x.CustomerTransName == selectedTransporter) && x.InvoiceDate.Date >= fromDate && x.InvoiceDate.Date <= toDate);

I think this should suffice:
List<Dispatch> objDispatch = (List<Dispatch>)Session["Data"];
List<Dispatch> filteredDispatches = objDispatch.Where(dispatch => dispatch.InvoiceDate.Date >= Convert.ToDateTime(FromDate).Date && dispatch.InvoiceDate.Date <= Convert.ToDateTime(ToDate).Date).ToList();
if (ddlTransporterName.SelectedItem.Text != "ALL")
{
filteredDispatches = filteredDispatches.Where(dispatch => dispatch.CustomerTransName == ddlTransporterName.SelectedItem.Text).ToList();
}

I think something like this should work:
List<Dispatch> objDispatch = (List<Dispatch>)Session["Data"];
var _fromDate = Convert.ToDateTime(FromDate);
var _toDate = Convert.ToDateTime(ToDate);
objDispatch = objDispatch
.FindAll(dispatch => Selector(
dispatch, ddlTransporterName.SelectedItem.Text, _fromDate, _toDate));
static bool Selector(
Dispatch dispatch, string name, DateTime fromDate, DateTime toDate)
{
if (dispatch.CustomerTransName == "ALL")
{
return dispatch.InvoiceDate.Date >= fromDate.Date
&& dispatch.InvoiceDate.Date <= toDate.Date;
}
return dispatch.CustomerTransName == name;
}