asp.net core simplifying linq query use in razor project

Marius Vasile

I am using below query and other similar in 90% of my pages. is there a way to have it in one file and call it from there?

var userId = User.FindFirstValue(ClaimTypes.NameIdentifier);
var orgid = await _context.UsersData.Where(s => s.Id == userId).Select(s => s.OrgID).FirstOrDefaultAsync();
WOAssetViews = await(from a in _context.WOAssetLocations.Where(s => s.OrgID == orgid)
join b in _context.WOAssetAssets on a.WOALId equals b.WOALId into TempData1
from c in TempData1.DefaultIfEmpty()
join d in _context.WOAssetEquipments on c.WOAId equals d.WOAId into TempData2
from e in TempData2.DefaultIfEmpty()
join f in _context.WOAssetComponents on e.WOAEId equals f.WOAEId into TempData3
from g in TempData3.DefaultIfEmpty()
select new WOAssetView
{
WOALId = a.WOALId,
AssetLocation = a.AssetLocation,
AssetID = c.AssetID,
AssetName = c.AssetName,
AssetManufacturer = c.AssetManufacturer,
EquipmentID = e.EquipmentID,
EquipmentName = e.EquipmentName,
EquipmentManufacturer = e.EquipmentManufacturer,
ComponentID = g.ComponentID,
ComponentName = g.ComponentName,
ComponentManufacturer = g.ComponentManufacturer
}).ToListAsync();

4 Replies

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Marius Vasile5y ago
Ok, I tried to put the query in a class
public List GetAssetView(string orgid)
        {
            if (!string.IsNullOrWhiteSpace(orgid))
            {
                List woassetview = new List();

                woassetview = (from a in _context.WOAssetLocations.Where(s => s.OrgID == orgid)
                               join b in _context.WOAssetAssets on a.WOALId equals b.WOALId into TempData1
                               from c in TempData1.DefaultIfEmpty()
                               join d in _context.WOAssetEquipments on c.WOAId equals d.WOAId into TempData2
                               from e in TempData2.DefaultIfEmpty()
                               join f in _context.WOAssetComponents on e.WOAEId equals f.WOAEId into TempData3
                               from g in TempData3.DefaultIfEmpty()
                               select new WOAssetView
                               {
                                   WOALId = a.WOALId,
                                   AssetLocation = a.AssetLocation,
                                   AssetID = c.AssetID,
                                   AssetName = c.AssetName,
                                   AssetManufacturer = c.AssetManufacturer,
                                   EquipmentID = e.EquipmentID,
                                   EquipmentName = e.EquipmentName,
                                   EquipmentManufacturer = e.EquipmentManufacturer,
                                   ComponentID = g.ComponentID,
                                   ComponentName = g.ComponentName,
                                   ComponentManufacturer = g.ComponentManufacturer
                               }).ToList();
            }

            return null;
        }
and call it with
public async Task OnGetAsync()
{
var userId = User.FindFirstValue(ClaimTypes.NameIdentifier);
var orgid = await _context.UsersData.Where(s => s.Id == userId).Select(s => s.OrgID).FirstOrDefaultAsync();  var repo = new AssetRepository(_context);
WOAssetViews = repo.GetAssetView(orgid);

return Page();
}
But I get error
System.NullReferenceException: 'Object reference not set to an instance of an object.'
+1
Sachin Singh5y ago
No sir,
an architecture always makes life easier.
However yes, you can simply create a class and the method you need and call them from page .
As , everything is in a single project , like edmx, your class and razor , so you don't need to think about references.
+1
Marius Vasile5y ago
It looks I am complicating my life even more with a Business layer. I was hoping to have it much simpler, a class that can be called from the cshtml.cs, similar with javascript code on view page
+1
Sachin Singh5y ago
yes create a business layer (class library)
create different classes for different business related work
create methods with parameters and pass the parameter from UI.
Though , i can guess that your entity are generated in UI layer so you need to split entity into another layer called
Business Object, for this you need to take a entity context generator template and specify edmx location.
+1