I have documents with property _report_type, it supposed to contain a string "FTE", or "CAB".
In legacy document, it can be null or not exist at all (undefined), they are supposed to be "ContractorWorkReport".
My mapping:
public class Order : Document, IBaseEntity<string>
{
[JsonProperty(Order = 70, PropertyName = "orderData")]
public OrderData Data { get; set; }
}
public class OrderData
{
[JsonProperty(Order = 60, PropertyName = "_order_type")]
public OrderType? OrderType { get; set; }
}
[JsonConverter(typeof(StringEnumConverter))]
public enum OrderType
{
[EnumMember(Value = "TFE")]
ContractorWorkReport,
[EnumMember(Value = "CAB")]
BudgetElectricMeter
}
My query based on that :
var query = _client.CreateDocumentQuery<T>($"/dbs/{_databaseId}/colls/{CollectionId}");
if (filter.OrderType.Value == OrderType.ContractorWorkReport)
query = query.Where(o => o.Data.OrderType == null || !o.Data.OrderType.HasValue || o.Data.OrderType == filter.OrderType);
else
query = query.Where(o => o.Data.OrderType == filter.OrderType);
This query crashes because of the o.Data.OrderType == null, error message is :
Unable to cast object of type 'Microsoft.Azure.Documents.Sql.SqlNullLiteral' to type 'Microsoft.Azure.Documents.Sql.SqlNumberLiteral'.'
How can fix this? Right now, i do this, but it's dirty...
if (filter.OrderType.Value == OrderType.ContractorWorkReport)
query = query.Where(o => o.Data.OrderType != OrderType.BudgetElectricMeter);
else
query = query.Where(o => o.Data.OrderType == filter.OrderType);
Thanks!
First, I would recommend you use this for the first parameter in CreateDocumentQuery : UriFactory.CreateDocumentCollectionUri(databaseId, collectionId)
To answer your question, you are comparing an int to a null. o.Data.OrderType, being an enum, resolves to an int. You may want to compare that to the default enum value 0 or query over documents where o.Data.OrderType is not a key at all
Related
[frangment of a linq query]
query.Select(c => new OdsSummaryResponse
{
Id = c.RISODS_Id,
Driver = c.CDGOREC.Where(a => a.CDGOREC_Conducente).FirstOrDefault().PERSONALE.PERSONE.PERSONE_CognomeNome,
Operators = c.CDGOREC.Where(a => myexternavar == true && !a.CDGOREC_Conducente && a.CDGOREC_PersonaleId != null).Select( d => new Operatori() {
Id = (int)d.CDGOREC_PersonaleId,
Nominativo = d.PERSONALE.PERSONE.PERSONE_CognomeNome,
Codice = d.PERSONALE.PERSONALE_Codice
}).ToList()
}).OrderByDescending(c => Id);
in the subquery Operators = c.CDGOREC.Where when an external variable myexternavar=false i'd like to completely hide the property "Operators" from the output.
But this code shows me an empty array,
{
"Id": 194214,
"Driver": "XXXXXXXX",
"OperatorsNo": 1,
"Operators": [] //i'd like to hide this property if myexternavar=false
}
is it possible to exclude the property at all???
You can use Conditional Property Serialization to instruct the Serializer when to include that property.
For example, the following will not emit the Operators property when it's either null or empty:
public class OdsSummaryResponse
{
// ...
public IList<Operatori> Operators { get; set;}
public bool ShouldSerializeOperators()
{
return this.Operators?.Count > 0;
}
}
I have a to add a specific requirement in a piece of code already implemented.
The data structure is something of this sort:
public class Module
{
public string Type;
public string ID;
public List<Point> Points = new List<Point>();
}
public class Point
{
public string Type;
public string Location;
public string Connection;
}
Originally LINQ was used to return all modules which certain characteristics
List<Module> miList = Modules.Where(m => m.Type != null
&& m.ID == "A"
&& m.Points.Where(t => t.Connection == ""
&& SimilarPoint(t.Type, x).ToList())
.Count() > 0)
.ToList();
with x an input to the function. The new requirement dictates that the modules returned shall all have points with Connection equal to "" and the same value in the Location field.
It seemed to me that the SelectMany could be used to this end, but I am not getting what I expected.
How should the function above be modified?
Thanks in advance
Not exactly sure what the SimilarPoint(t.Type, x) does here.
May be you should try something like this and find out if it works for you -
var resultSet = Modules.Where(m => !string.IsNullOrEmpty(m.Type) && m.ID.Equals("A"))
.Select(n =>
new Module {
Type=n.Type,
ID=n.ID,
Points= n.Points.Where(p => String.IsNullOrEmpty(p.Connection) && String.IsNullOrEmpty(p.Location)).ToList()
})
.ToList();
You said all the returned modules have the same Location, but that doesn't explain how you select which Location so I arbitrarily picked the first matching module's location:
var miQuery1 = Modules.Where(m => m.Type != null
&& m.ID == "A"
&& m.Points.Where(t => t.Connection == ""
&& SimilarPoint(t.Type, x).ToList()).Count() > 0)
.Where(m => m.Points.All(p => p.Connection == ""));
var miQuery2 = miQuery1.Where(m => m.Location == miQuery1.First().Location);
List<Module> miList = miQuery2.ToList();
I have the following code :
public ViewResult Stock(Guid id)
{
// Get the product form the database
var product = productRepository.GetById(id);
var viewModel = new ProductStockViewModel()
{
Product = product,
ProductStoreStock = storeDB.Stores.Select(store => new ProductStoreStockViewModel()
{
Store = store,
Bought = storeDB.Stocks
.Where(s => s.StoreId == store.StoreId)
.Where(p => p.ProductId == product.ProductId)
.Sum(s => s.Quantity),
Sold = storeDB.OrderDetails
.Where(o => o.Order.StoreId == store.StoreId)
.Where(o => o.ProductId == product.ProductId)
.Sum(s => s.Quantity)
})
.ToList()
};
return View(viewModel);
}
public class ProductStoreStockViewModel
{
public Store Store { get; set; }
//public Product Product { get; set; }
public decimal Bought = 0;
public decimal Sold = 0;
public decimal Stock
{
get { return Bought - Sold; }
}
}
I understad the error, sometimes a product has been sold 0 times so .Sum(s => s.Quantity) returns a null value. I know I can use ?? 0 if that condition is meet but what's the most elegant way to express that in Linq method syntax?
Your problem can be when 'storeDB.Stocks' is null or 'storeDB.OrderDetails' is null (but here you'll get null execption). In other way, you could remove 1 where in your query for more elegant code, like this
Sold = storeDB.OrderDetails
.Where(o => o.Order.StoreId == store.StoreId && o.ProductId == product.ProductId)
.Sum(s => s.Quantity)
And as Cédric Bignon said 'Sold' will be '0' if query empty but not null.
I would like to optimize following lines of code for Sorting.
public ViewResult Index(string sortorder, int? pagesize, int? page)
{
int pageSize = pagesize ?? 10;
if (Request.HttpMethod != "GET")
{
page = 1;
pageSize = 10;
}
ViewBag.SelectedPageSize = pageSize;
ViewBag.CurrentSort = sortorder;
ViewBag.FirstNameSortParm = String.IsNullOrEmpty(sortorder) ? "FirstName desc" : "";
ViewBag.LastNameSortParm = sortorder == "LastName" ? "LastName desc" : "LastName";
ViewBag.DepNameSortParm = sortorder == "depName" ? "depName desc" : "depName";
var joined = from tm in db.TabMasters select tm;
switch (sortorder)
{
case "FirstName":
joined = joined.OrderBy(m => m.FirstName);
break;
case "FirstName desc":
joined = joined.OrderByDescending(m => m.FirstName);
break;
case "LastName":
joined = joined.OrderBy(m => m.LastName);
break;
case "LastName desc":
joined = joined.OrderByDescending(m => m.LastName);
break;
case "depName":
joined = joined.OrderBy(m => m.depName);
break;
case "depName desc":
joined = joined.OrderByDescending(m => m.depName);
break;
default:
joined = joined.OrderBy(m => m.FirstName);
break;
}
int pageIndex = (page ?? 1) - 1;
int start = (pageIndex * pageSize);
ViewBag.TotalRecord = joined.Count();
ViewBag.StartRecord = start + 1;
ViewBag.EndRecord = ((start + pageSize) >= ViewBag.TotalRecord) ? ViewBag.TotalRecord : (start + pageSize);
return View(joined.ToPagedList(pageIndex, pageSize));
}
Because this is very tedious way if i have more the 10 fields to perform sort.
Thanks,
Imdadhusen
It's a bit vague to me what your actual goal is but for the switch part you could use an extension method as the below.
public static class SortExtensions
{
public static IEnumerable<T> SortByField<T>(this IEnumerable<T> sequence, string sortOrder)
{
var tokens = sortOrder.Trim().Split(' ');
var field = tokens[0];
var direction = tokens.Skip(1).Single().ToLower();
var prop = typeof(T).GetProperty(field);
return direction == "desc"
? sequence.OrderByDescending(m => prop.GetValue(m, null))
: sequence.OrderBy(m => prop.GetValue(m, null));
}
}
It will make a very simplified parsing of the sort order. It puts the responsibility on the calling party which is generally not what you want to do, so you might want some error handling in case the sortorder string does not fulfill the requirements.
from the sortorder string it fetches a name used to identify a property which can be used to fetch the value used for sorting.
you can use it like this:
db.TabMasters.SortByField(sortOrder)
EDIT based on comment:
The line typeof(T).GetProperty(field) is fragile in the absence of any error handling. It relies on the first token to be a name of a public property of the type T. It will return null if the name doesn't match a property. Including if it matches a Field name. A similar function exist for getting a FieldInfo
prop.GetField(field) will return a fieldinfo object of there's a public field with the given name otherwise null. To get the value of a field simply omit the last parameter to the GetValue call.
You should take a look at Linq.DynamicQuery.
There's more info in this blogpost http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
The library lets you write following code:
var query = northwind.Products
.Where("CategoryID = 3 AND UnitPrice > 3")
.OrderBy("SupplierID");
instead of
var query = from p in northwind.Products
where p.CategoryID == 3 && p.UnitPrice > 3
orderby p.SupplierID
select p;
If you want to add the sortdirection:
var query = northwind.Products.OrderBy("SupplierID Descending");
//Below mentioned class is created to understand the problem, while this is created through Linq2Sql.
public class JobAds
{
public int ID { get; set; }
public int EmployerRef { get; set;}
}
int? employerId = null;
var jobAdListing = JobAds.Where
( n => (!employerId.HasValue || n.EmployerRef == employerId.Value )).ToList();
The Issue is I'm getting "Nullable object must have a value." at the above line. After doing some debugging, I feel n.EmployerRef == employerId.Value is making some trouble, but unable to find anything good.
Just write liks this, you don't have to worry about the null values (since NULL == NULL equals false)
int? employerId = null;
var jobAdListing = tblCompanies.Where
(n => (n.fkUserID_responsible == employerId)).ToList();
Or you can keep your code and just remove the ".value"
var jobAdListing = JobAds.Where
( n => (!employerId.HasValue || n.EmployerRef == employerId)).ToList();
in my local playground a simmilar case works with this easiest approach:
using (UnitOfWork.Begin("LinqToSql"))
{
Guid? id1 = null;
Guid? id2 = this.personRepository.GetAll().First().FavouriteProjectId;
var all = this.personRepository.GetAll().Where(o => o.FavouriteProjectId == id1 || o.FavouriteProjectId == id2).ToArray();
}
for you, this should work too:
int? employerId = null;
int? employerType = null; /* OTHER Conditions */
var list = JobAds.Where(n => n.EmployerRef == employerId &&
n.EmployerTypeRef == employerType)).ToArray();