Develop Reference

Implement ASP.NET MVC5 search functionality using 2 tables

I have created two tables: Claim and ClaimAttachments.
I'm trying to join them on ClaimID in order to get the filtered data from both the tables.
public ActionResult Index(int? search)
{
if (search!=null)
{
var Product = (from P in db.Claims
join C in db.ClaimAttachments on
P.ClaimID equals C.ClaimID
select new Claim
{
ClaimID = P.ClaimID,
ClaimBatchID = P.ClaimBatchID,
PatientControlNumber = P.PatientControlNumber,
PatientFirstName = P.PatientFirstName,
PatientLastName = P.PatientLastName,
ServiceFromDate = P.ServiceFromDate,
ServiceToDate = P.ServiceToDate,
});
return View(db.Claims.Where(x => x.ClaimID == search).ToList());
}
else
{
return View(db.Claims.ToList());
}
I'm able to get the searched result but from single table. The join is not working.

Currently you're only selecting from the Claims data:
return View(db.Claims.Where(x => x.ClaimID == search).ToList());
You have a join query just above that line of code:
var Product = (from P in db.Claims
join C in db.ClaimAttachments on
P.ClaimID equals C.ClaimID
select new Claim
{
ClaimID = P.ClaimID,
ClaimBatchID = P.ClaimBatchID,
PatientControlNumber = P.PatientControlNumber,
PatientFirstName = P.PatientFirstName,
PatientLastName = P.PatientLastName,
ServiceFromDate = P.ServiceFromDate,
ServiceToDate = P.ServiceToDate
});
But you don't do anything with the results of that query. It sounds like you meant to use the results of that query (which is in the Product variable, which incidentally should probably have a plural name since it's a collection) instead of just selecting from db.Claims. Something like this:
return View(Product.Where(x => x.ClaimID == search).ToList());
Note however that you're still only selecting data from one table. Though the join operation may alter the results of that selection. But the selection itself is here:
select new Claim
{
ClaimID = P.ClaimID,
ClaimBatchID = P.ClaimBatchID,
PatientControlNumber = P.PatientControlNumber,
PatientFirstName = P.PatientFirstName,
PatientLastName = P.PatientLastName,
ServiceFromDate = P.ServiceFromDate,
ServiceToDate = P.ServiceToDate
}
Notice how every value selected is from the P alias, which is defined here:
from P in db.Claims
So you're successfully joining the two tables, but only selecting data from one of the two tables. If you want to also select data from the other table then, well, you need to select data from the other table. For example, if there's a property on that table called SomeProperty that you want to select then you'd need to select it, and into an object which has that property.
For example, you might create a view model (let's call it ClaimViewModel as an example) which represents a combined record of the two tables, containing the properties you want from each. Then you'd select into that type:
select new ClaimViewModel
{
ClaimID = P.ClaimID,
ClaimBatchID = P.ClaimBatchID,
PatientControlNumber = P.PatientControlNumber,
PatientFirstName = P.PatientFirstName,
PatientLastName = P.PatientLastName,
ServiceFromDate = P.ServiceFromDate,
ServiceToDate = P.ServiceToDate,
SomeProperty = C.SomeProperty // <--- here
}
This would select the combined data into a list of ClaimViewModel objects, which you'd then filter based on your "search" and return to your view just like you do with the Claims objects now. And of course that view would need to be updated to expect a collection of ClaimViewModel objects instead of a collection of Claim objects.

Linq - Linq expression different context error

I have 3 tables
- ERPEntry
- ERPEntryType
- ERPApp
I am trying to get data from these 3 tables using the below query but i got the error :
specified linq expression contains references to queries that are
associated with different contexts
var erpEntryInfo = (from s in ERPDB.ERPEntrys
JOIN t in ERPDB.ERPEntryTypes
on s.EntryTypeID equals t.EntryTypeID
join a in APPDB.ERPApps
on s.AppId equals a.AppId
where s.UserIDAdded == '250176'
select new ERPInfo
{
EntryId = s.EntryID,
EntryType = t.EntryTypeName,
ERPApp = a.ApplicationName,
DateAdded = s.DateAdded
}).OrderByDescending(d => d.DateAdded).Take(10).ToList();
I searched based on the errror and tried to split the above query into 2 as below.
var res = (from s in ERPDB.ERPEntrys
join t in ERPDB.ERPEntryTypes
on s.EntryTypeID equals t.EntryTypeID
where s.UserIDAdded == '250176'
select new {s.EntryTypeID, s.DateAdded, t.EntryTypeName, s.AppID }).OrderByDescending(d => d.DateAdded).Take(10).ToArray();
var y = (from a in APPDB.ERPApps
join b in res on a.AppId equals //??//
select new ERPInfo
{
EntryId = b.EntryID,
EntryType = b.EntryTypeName,
ERPApp = a.ApplicationName,
DateAdded = b.DateAdded
}).ToList();
I am having an issue in the above query to access AppId which i got into the result res..i commented with //??// in the above code
can i get any help on this.

how to select records from multiple table with max count value from one table using Linq in Asp.net MVC C#

I have 3 tables:
1. Tbl_Model,
2. Tbl_ModelImg,
3. Tbl_Category
I want to know how to fetch the records from these 3 tables using categoryId.
The single model may have multiple images, but I want to show all the products of that category with their images. The problem is I only want a single image in that view. So when a user clicks on that particular model, the details of that model and all its images will show on the next view.
The following query is working fine but it displays all the images with their model name. Means If a model has 4 images than on category details page it displays 4 items with the same name and different images.
Here is the model class :
public class showdata
{
public Tbl_ModelImg tmi { get; set; }
public Tbl_Model tm { get; set; }
public Tbl_SubCategory tblsubcategory { get; set; }
}
public ActionResult Categorydetails(string sid)
{
var sId = Int64.Parse(new
StandardModule().Decrypt(HttpUtility.UrlDecode(sid.ToString())));
try
{
var query = (from c in db.Tbl_Model
join o in db.Tbl_ModelImg
on c.Model_Id equals o.Model_Id
join d in db.Tbl_SubCategory on c.SubCategory_Id
equals d.Id
where c.SubCategory_Id == sId
select new showdata()
{
tm = c,
tmi = o,
tblsubcategory = d
}).OrderByDescending(d => d.tm.Id).ToList();
return View(query);
}

Replace the second line of the LINQ query with
join o in db.Tbl_ModelImg.GroupBy(m => m.Model_Id).Select(m => m.First())
The GroupBy() will group the items in Tbl_ModelImg by Model_Id and then the Select() will cut the contents of the resulting dataset down to just the first item in each group.
Once the where clause restricts your results to just those that items that join to the correct SubCategory_Id then you have what you need.

var query = (from c in db.Tbl_Model
join o in db.Tbl_ModelImg.GroupBy(m => m.Model_Id).Select(m
=> m.FirstOrDefault())
on c.Model_Id equals o.Model_Id
join d in db.Tbl_SubCategory on c.SubCategory_Id equals d.Id
where c.SubCategory_Id == sId
select new showdata()
{
tm = c,
tmi = o,
tblsubcategory = d
}).OrderByDescending(d => d.tm.Id).ToList();

How to assign values to a list by linq without for or foreach statements?

I want to compare two lists and assign 1st list to another in case of requirement.
var getdetail=_readonlyservice.getdetail().ToList();
foreach(var item in docdetail)
{
var temp=getdetail.firstordefualt(i=>i.Id=item.Id)
if(temp==null) continue;
item.code=temp.code;
}
I want to implement top statements in linq .any help ?

Think so..
var getdetail=_readonlyservice.getdetail().ToList();
var tempList = from dd in context.docdetail
join g in context.getdetail on dd.Id equals g.Id
select new // Your type
{
// Columns...
Code = g.Code
}

I believe you are trying to do like the way I did, although I was going to join table.
var result = (from e in DSE.employees
join d in DSE.departments on e.department_id equals d.department_id
join ws in DSE.workingshifts on e.shift_id equals ws.shift_id
select new
{
FirstName = e.FirstName,
LastName = e.LastName,
Gender = e.Gender,
Salary = e.Salary,
Department_id = e.department_id,
Department_Name = d.department_name,
Shift_id = ws.shift_id,
Duration = ws.duration,
}).ToList();
// TODO utilize the above result
I was using DTO method to do this. And then you return result(as this case is result).
You may view the whole question and solution here.
As this case, you are not required to put foreach loop, as the query said from every row in yourdatabase.table

How to group rows using LINQ to Entity separating values with commas?

Below is my LINQ Query, that im using to select ITEMS:
protected void Page_Load(object sender, EventArgs e)
{
whatsmydiscountEntities ctx = new whatsmydiscountEntities();
int IdRelationshipItems = Convert.ToInt32(Request.QueryString["IdRelationshipItems"]);
int IdProductService = Convert.ToInt32(Request.QueryString["IdProductService"]);
var Items = (from es in ctx.State
join ie in ctx.ItemsStates on es.StateId equals ie.StateId
join i in ctx.Items on ie.IdItem equals i.IdItem
join iir in ctx.ItemsRelationshipItems on i.IdItem equals iir.IdItem
join ir in ctx.RelationshipItems on iir.IdRelationshipItems equals ir.IdRelationshipItems
join ips in ctx.ItemsProductsServices on i.IdItem equals ips.IdItem
join ps in ctx.ProductsServices on ips.IdProductService equals ps.IdProductService
where iir.IdRelationshipItems == IdRelationshipItems
&& ips.IdProductService == IdProductService
&& ir.Active == 1
&& i.Active == 1
select new
{
ItemName = i.Name,
StateSigla = es.Sigla,
ProductServiceName = ps.Ttitle,
RelationshipItemName = ir.Name,
RelationshipItemImage = ir.Image,
RelationshipItemActive = ir.Active,
ItemSite = i.Site,
ItemDescription = i.Description,
ItemAddress = i.Address,
Iteminformationdiscount = i.information_discount,
ItemLogo = i.Logo,
ItemActive = i.Active,
StateId = ie.StateId,
IdRelationshipItems = iir.IdRelationshipItems,
IdProductService = ips.IdProductService
}).ToList();
}
As you can see, the result will be 1 row for each state, if the user passes the IdRelationshipItems and the IdProductService.
Instead of 1 row for each state with the same information, I'd like to show only 1 row and all the states separated by commas. What do I need to change to do this?

I had to solve this problem today. I have a view model that looks like this:
public class IndexViewModel
{
public string Search { get; set; }
public IPagedList<MembershipUser> Users { get; set; }
public IEnumerable<string> Roles { get; set; }
public bool IsRolesEnabled { get; set; }
public IDictionary<string,string> Tags { get; set; }
}
I needed to return a unique list of users and all of the Tags that are assigned to them as a comma separated string.
The data is stored like this:
"41FFEC0F-B920-4839-B0B5-862F8EDE25BD", tag1
"41FFEC0F-B920-4839-B0B5-862F8EDE25BD", tag2
"41FFEC0F-B920-4839-B0B5-862F8EDE25BD", tag3
And I needed output that looked something like this:
"41FFEC0F-B920-4839-B0B5-862F8EDE25BD", "tag1, tag2, tag3"
I ended up creating a List of UserId's like this (I'm using the MembershipProvider which exposes the UserId as ProviderUserKey):
var userIdList = users.Select(usr => (Guid) usr.ProviderUserKey).ToList();
The object "users" is a MembershipUser object. I then call a function in my service passing the List in like this:
Tags = _usersTagsService.FindAllTagsByUser(userIdList)
And my service function looks like this:
public IDictionary<string, string> FindAllTagsByUser(IList<Guid> users)
{
var query = (from ut in _db.UsersTags
join tagList in _db.Tags on ut.TagId equals tagList.Id
where users.Contains(ut.UserId)
select new {ut.UserId, tagList.Label}).ToList();
var result = (from q in query
group q by q.UserId
into g
select new {g.Key, Tags = string.Join(", ", g.Select(tg => tg.Label))});
return result.ToDictionary(x=>x.Key.ToString(),y=>y.Tags);
}
I'm pretty sure these two linq statements can probably be combined into one but I find it easier to read this way. Still only hits the database once.
Things to watch out for:
I was originally passing just IList users into the function FindAllTagsByUser and linq couldn't infer the type and therefore wouldn't let me use the .Contains extension method. Kept saying that linq to entities didn't support Contains.
You need to do a .ToList() on the first query to materialize it or you will get trouble from linq to entity when you try to use string.Join to create the comma separated list.
Good luck
dnash