Develop Reference

dynamic fields sorting in elasticsearch and.net

I am trying to sort records based on dynamic field names sent to the search API.
the d19FilterCriteria object gives me the field name(SortOn) and the order(SortOrder) for sorting. I have used a sort descriptor for this purpose.
var sortDescriptor = new SortDescriptor<MPANStatus>();
// If Field Name is Dynamic
if (d19FilterCriteria.SortOrder == "asc")
{
sortDescriptor.Field(d19FilterCriteria.SortOn, Nest.SortOrder.Ascending);
}
else if (d19FilterCriteria.SortOrder == "desc")
{
sortDescriptor.Field(d19FilterCriteria.SortOn, Nest.SortOrder.Descending);
}
var result = await _elasticClient.SearchAsync<MPANStatus>(s => s
.Index("ampower-mpanstatusindex")
.Skip(skip)
.Size(pageSize)
.Sort(sort =>
{
sort = sortDescriptor;
return sort;
})
While debugging the sort descriptor shows me an object that has a valid value for Name and order
This query returns empty list for this code. Could I know what the issue here is?

You can have list of sort order based on your inputs:
List<ISort> sdBookSortOrder = new List<ISort>();
SortOrder oSortOrder = SortOrder.Ascending; //SortOrder.Descending;
sdBookSortOrder.Add(new FieldSort { Field = <sField1>, Order = oSortOrder });
sdBookSortOrder.Add(new FieldSort { Field = <sField2>, Order = oSortOrder });
And, you can use above sort order collection while sending search request - as shown below:
ISearchRequest searchRequest = new SearchRequest(SearchEngine.IndexName)
{
From = iFrom,
Size = iSize,
Query = query,
Sort = oSortOrder,
};
I hope, it will solve your problem.
Regards,
Nikunj

My guess is since you are using the dynamic mapping, the string will be considered as text field and sub field keyword
use field.keyword instead of just field

The better approach to work with dynamic sorting fields using NEST, it's using SortDescriptor
SortDescriptor<dynamic> sort = GetSorting(request.Sorting);
ISearchResponse result = elasticClient.Search<YourType>(s => s
.Index("your-index")
.Sort(s => sort));
Use this method to add a list of sorting
// method to generate the Sorting
public SortDescriptor<dynamic> GetSorting(List<Sort>? sorting)
{
SortDescriptor<dynamic> sortDescriptor = new();
if (sorting != null)
{
foreach (Sort sort in sorting)
sortDescriptor.Field(sort.Field, getOrder(sort.Order));
}
return sortDescriptor;
}
class "Sort" just to store Field and Order values
public string Field { get; set; }
public string Order { get; set; }

Filter null properties from list using Linq

I have a method that accepts a variable that has a list of properties connected to it. What I need to do is create a linq query that will flag the current variable coming in as missing an "address" and add it to a list.
public void Teachers(List<Teacher> teachers)
{
foreach (Name name in teachers)
{
int age = program.CalculateAge(name.BirthDate.Year);
Name address = FilterAddress(name);
// Output Teachers Name - First Name, Last Name
if (name.Type.Equals(Name.NameType.Teacher))
{
OutputToConsole(name.FirstName, name.LastName, age);
program.WriteAddress(name);
}
}
Console.WriteLine();
}
Above is the method that will add the current variable in foreach loop to the FilterAddress Method. Below is where the variable is being passed. This variable has a List property named "Address" that is connected to it. This address can be null. I need to select each name with an address of null and add it to a list. But as you guessed, my LINQ code below doesn't work and just breaks.
public Name FilterAddress(Name name)
{
var NullItems = name.Select(x => x.Addresses).OfType<Name>();
return NullItems;
}

public Name[] FilterAddress(Name name)
{
return name.Where(x => string.IsNullOrEmpty(x.Addresses))
.Select(x => x.Name)
.ToArray();
}

Only need to add the "if null" check in the query to return if Adresses is null.
var NullItems = name.Where(x => x.Addresses == null);

Cannot implicitly convert type '.List<AnonymousType#1>' to '.List<WebApplication2.Customer>'

In the following code that returns a list:
public List<Customer> GeAllCust()
{
var results = db.Customers
.Select(x => new { x.CustName, x.CustEmail, x.CustAddress, x.CustContactNo })
.ToList()
return results;
}
I get an error reporting that C# can't convert the list:
Error: Cannot implicitly convert type System.Collections.Generic.List<AnonymousType#1> to System.Collections.Generic.List<WebApplication2.Customer>
Why is that?
Here's a screenshot showing some additional information that Visual Studio provides in a tooltip for the error:
Is it right way to return some columns instead of whole table....?
public object GeAllCust()
{
var results = db.Customers.Select(x => new { x.CustName, x.CustEmail, x.CustAddress, x.CustContactNo }).ToList();
return results;
}

When you look the code:
x => new { ... }
This creates a new anonymous type. If you don't need to pull back only a particular set of columns, you can just do the following:
return db.Customers.ToList();
This assumes that Customers is an IEnumerable<Customer>, which should match up with what you are trying to return.
Edit
You have noted that you only want to return a certain subset of columns. If you want any sort of compiler help when coding this, you need to make a custom class to hold the values:
public class CustomerMinInfo
{
public string Name { get; set; }
public string Email { get; set; }
public string Address { get; set; }
public int? ContactNumber { get; set; }
}
Then change your function to the following:
public List<CustomerMinInfo> GetAllCust()
{
var results = db.Customers.Select(x => new CustomerMinInfo()
{
Name = x.CustName,
Email = x.Email,
Address = x.Address,
ContactNumber = x.CustContactNo
})
.ToList();
return results;
}
This will work, however, you will lose all relationship to the database context. This means if you update the returned values, it will not stick it back into the database.
Also, just to repeat my comment, returning more columns (with the exception of byte arrays) does not necessarily mean longer execution time. Returning a lot of rows means more execution time. Your function is returning every single customer in the database, which when your system grows, will start to hang your program, even with the reduced amount of columns.

You are selecting to an anonymous type, which is not a Customer.
If you want to do (sort of) this, you can write it like this:
return db.Customers.Select(x => new Customer { Name = x.CustName, Email = x.CustEmail, Address = x.CustAddress, ContactNo = x.ContactNo }).ToList();
This assumes the properties on your Customer object are what I called them.
** EDIT ** Per your comment,
If you want to return a subset of the table, you can do one of two things:
Return the translated form of Customer as I specified above, or:
Create a new class for your business layer that only has only those four fields, and change your method to return a List<ShrunkenCustomer> (assuming ShunkenCustomer is the name that you choose for your new class.)

GetAllCust() is supposed to return a List of Customer, Select New will create a list of Anonymous Types, you need to return a list of Customer from your query.
try:
var results = db.Customers.Select( new Customer{CustName = x.CustName}).ToList(); //include other fields

I guess Customer is a class you have defined yourself?
The my suggestion would be to do something like the following:
var results = db.Customers.Select(x => new Customer(x.Custname, x.CustEmail, x.CustAddress, x.CustContactNo)).ToList();
The reason is that you are trying to return a list of Customer but the results from your link is an anonymous class containing those four values.
This would of course require that you have a constructor that takes those four values.

Basically whatever u got in var type, loop on that and store it in list<> object then loop and achieve ur target.Here I m posting code for Master details.
List obj = new List();
var orderlist = (from a in db.Order_Master
join b in db.UserAccounts on a.User_Id equals b.Id into abc
from b in abc.DefaultIfEmpty()
select new
{
Order_Id = a.Order_Id,
User_Name = b.FirstName,
Order_Date = a.Order_Date,
Tot_Qty = a.Tot_Qty,
Tot_Price = a.Tot_Price,
Order_Status = a.Order_Status,
Payment_Mode = a.Payment_Mode,
Address_Id = a.Address_Id
});
List<MasterOrder> ob = new List<MasterOrder>();
foreach (var item in orderlist)
{
MasterOrder clr = new MasterOrder();
clr.Order_Id = item.Order_Id;
clr.User_Name = item.User_Name;
clr.Order_Date = item.Order_Date;
clr.Tot_Qty = item.Tot_Qty;
clr.Tot_Price = item.Tot_Price;
clr.Order_Status = item.Order_Status;
clr.Payment_Mode = item.Payment_Mode;
clr.Address_Id = item.Address_Id;
ob.Add(clr);
}
using(ecom_storeEntities en=new ecom_storeEntities())
{
var Masterlist = en.Order_Master.OrderByDescending(a => a.Order_Id).ToList();
foreach (var i in ob)
{
var Child = en.Order_Child.Where(a => a.Order_Id==i.Order_Id).ToList();
obj.Add(new OrderMasterChild
{
Master = i,
Childs = Child
});
}
}

Use a numeric value in a linq dynamic query string

I am trying to make a dynamic linq query that will check for values based on a string.
First of all, here's the query:
objQry = from o in m_Db.OBJECTS.Where(whereConditions)
select o;
if(!objQry.Any())
{
return null;
}
The whereConditions variable is a string I build and pass as parameter to find out the values I need. Here's examples of valid string:
OBJ_NAME == \"Sword\" and OBJ_OWNER == \"Stan\"
This will return any item whose name is "Sword" and owner is "Stan;
OBJ_COLOR == \"Blue\" OR OBJ_COLOR == \"Red\"
This will return any item which color is either blue or red.
Up to there, I'm fine, but now I have a problem: I need to check a decimal field. So I've tried this string:
OBJ_NUMBER == 1
But the query returns null even if there are objects which OBJ_NUMBER value is 1. It's a decimal. How can I indicate the query that they need to check for a decimal value?
**** EDIT ****
I have tried to "modify" the value passed so that it looks like this:
"CARD_NUMBER == Convert.ToDecimal(1)"
And now I have a different kind of error telling me this:
LINQ to Entities does not recognize the method 'System.Decimal ToDecimal(Int32)' method, and this method cannot be translated into a store expression.
Any clues anyone? I'm still looking for a way to do this. Thanks!
EDIT 2
You can get an example of how my code is shaped by looking at this question.
Let's come back at this problem. I want to check decimal values. Let's say that OBJ_NUMBER is a decimal field.
Using Dynamic Linq, I tried to read the decimal field. Say that I want to get each object which number is 1.27. The whereConditions field would then be shaped like this:
OBJ_NUMBER == 1.27
But then I would get an Invalid real literal '1.27' error. I don't know why.
So I have tried Gert Arnold's solution and done this instead:
decimal bDecimal = decimal.Parce(valueToParse);
param = new ObjectParameter("cardNumber", typeof(decimal)) { Value = bDecimal };
valuesToUse.Add("CARD_NUMBER == #cardNumber");
listParams.Add(param);
But I ended up having 2 problems:
The first problem is that my whereConditions string is shaped this way:
CARD_NUMBER == #cardNumber
But I get the following error:
No property or field 'cardNumber' exists in type 'CARD'
Leading me to believe that it cannot make the link between the object parameter and the string used to do the query.
As you can see, I have a list of Params. This is because I cannot know for sure how many parameters the user will chose. So each time the user enters a new search field, I have to create a new ObjectParameter and store it in a list. Here's how I try to do the thing after:
ObjectParameter[] arrayParameters = listParams.ToArray();
// Convert the list to an array
And then, when I try to make the query:
cardQry = from c in mDb.CARD.Where(whereConditions, arrayParameters)
select c;
But to no avail.
RESULTS
Based on the answered question below, I have developped something "awful", yet functional.
First of all, I ignore every decimal fields because I could never reach them with dynamic linq. Instead, I do this:
var valuesToParse = keyValuePair.Value.Split(new[] {' '}, StringSplitOptions.RemoveEmptyEntries);
// Here I parse the value and, if that's the case, the symbol.
decimal baseValue = decimal.Parse(valuesToParse[0]);
if (valuesToParse.Count() > 1)
{
string baseMethod = valuesToParse[1];
if (baseMethod == ">" || baseMethod == ">=")
{
if (baseMethod == ">=")
{
baseValue--;
}
// The list is actually like this: Dictionary<string, object> list = new Dictionary<string, object>();
list.Add("low", baseValue);
// I kind of activate a tag telling me that the user is looking for a higher value.
cardHigher = true;
}
else
{
if (baseMethod == "<=")
{
baseValue++;
}
list.Add("low", baseValue);
cardLower = true;
}
}
else
{
//lowParam = new ObjectParameter("dec", typeof(decimal)) { Value = baseValue };
list.Add("low", baseValue);
}
cardNumberActivated = true;
At the end, when I get the list of objects, I do this:
if (list.Count > 0)
{
(example)
if (cardNumberActivated)
{
if (cardHigher)
{
q = mDb.CARD.Where("CARD_NUMBER >= #0", list["low"]).ToList();
}
else if (cardLower)
{
q = mDb.CARD.Where("CARD_NUMBER <= #0", list["low"]).ToList();
}
else
{
q = mDb.CARD.Where("CARD_NUMBER == #0", list["low"]).ToList();
}
}
}
// Here we get the orinalData with the basic filters.
listToReturn.AddRange(cardQry);
if (q != null)
{
//listToReturn.AddRange(q);
for (int i = 0; i < listToReturn.Count; i++)
{
var priceList1 = listToReturn[i];
if (!q.Any(_item => _item.CARD_NUMBER == priceList1.CARD_NUMBER))
{
listToReturn.RemoveAt(i);
i--;
}
}
}
And it works. This is not an elegant way to make it work, but I can validate the fields the way I wanted, and for this, I am thankful at last.

You should not build a query string with inline predicate values. Use parameters in stead. Then will also be able to specify the type:
var whereConditions= "it.CARD_NUMBER = #cardNumber";
var param = new ObjectParameter("cardNumber", typeof(decimal)) { Value = 1 };
objQry = from o in m_Db.OBJECTS.Where(whereConditions, param);
Edit
I don't know what doesn't work in your code. Here's just a random piece of working code derived from one of my own projects:
var param1 = new ObjectParameter("dec", typeof(decimal)) { Value = 90000m };
var param2 = new ObjectParameter("int", typeof(int)) { Value = 90000 };
var q = ValueHolders.Where("it.DecimalValue >= #dec OR it.IntegerValue > #int",
param1, param2).ToList();
Note that param1, param2 could also be an array of ObjectParameter.

Why I can't remove item from ObservableCollection?

I filled some ObservableCollection<Employe> collection:
// Program.Data.Employees - it is ObservableCollection<Employe>.
Program.Data.Employees.Add(new Employe() { Name="Roman", Patronymic="Petrovich", Surname="Ivanov" });
Program.Data.Employees.Add(new Employe() { Name = "Oleg", Patronymic = "Vladimirovich", Surname = "Trofimov" });
Program.Data.Employees.Add(new Employe() { Name = "Anton", Patronymic = "Igorevich", Surname = "Kuznetcov" });
In other place of my code I try to remove some item from this collection:
// Program.Data.Employees - it is ObservableCollection<Employe>.
Employe x = Program.Data.Employees.First(n => n.Guid == emp.Guid); // x is not null.
Int32 index = Program.Data.Employees.IndexOf(x); // I got -1. Why?
Boolean result = Program.Data.Employees.Remove(x); // I got 'false', and item is not removed. Why?
// But this works fine:
Program.Data.Employees.Clear();
I can clear collection, but I can't remove necessary item. Why it happens?
UPD: Equals method of my Employe class
public bool Equals(Employe other) {
return
other.Guid == this.Guid &&
String.Equals(other.Name, this.Name, StringComparison.CurrentCultureIgnoreCase) &&
String.Equals(other.Patronymic == this.Patronymic, StringComparison.CurrentCultureIgnoreCase) &&
String.Equals(other.Surname == this.Surname, StringComparison.CurrentCultureIgnoreCase) &&
other.Sex == this.Sex &&
String.Equals(other.Post == this.Post, StringComparison.CurrentCultureIgnoreCase);
}

I tried the following code to reproduce your error:
class Employee
{
public string Name { get; set; }
public Guid Guid { get; set; }
}
// ...
ObservableCollection<Employee> employees = new ObservableCollection<Employee>();
var guid1 = Guid.NewGuid();
employees.Add(new Employee { Name = "Roman", Guid = guid1 });
employees.Add(new Employee { Name = "Oleg", Guid = Guid.NewGuid() });
var x = employees.First(e => e.Guid == guid1);
var index = employees.IndexOf(x); // index = 0, as expected
var result = employees.Remove(x); // result = true, as expected
It worked as expected. I would suggest, you set a breakpont at var x = ... and check, if
The collection really contains the item you're looking
If First() really returns that item
Then go to the next line and check, if index is returned correctly. And finally check again, if result is really false.
I see several possible causes of your code failing:
You didn't post the full code and something happens between x=Program.Data.Employees.First() and Program.Data.Employees.IndexOf()
You use multithreaded code (which also results in "something happening" between the two statements). In this case, you need to synchronize the access to the collection
You don't use a ObservableCollection directly but some derived class instead which is constructed by your data layer (such as DataServiceCollection, but this one should work fine too). In this case, check the actual type of your collection in the debugger
Another typical cause of errors with collection would be, if you try to remove items while iterating over the collection (i.e. inside a foreachloop): but in this case an exception should be thrown (and IndexOf should work fine), so this would only apply if you use some derived class which implements non-standard behaviour.
EDIT (in return to you posting your Equal method)
Your Equal method has a serious error in it:
String.Equals(other.Patronymic == this.Patronymic, StringComparison.CurrentCultureIgnoreCase)
... // applies also for following comparisons
should be
String.Equals(other.Patronymic, this.Patronymic, StringComparison.CurrentCultureIgnoreCase)
...
Also, if you're using a Guid, consider only comparing the GUIDs, since this usually means 'unique identifier', so it should be enough to identify some entity.