I am working on Entity Framework 6 in C# .NET CORE 2.0 application. I have requirement to get role id from database where roleName = x and add role reference to user as in one: many table
I want to avoid 2 trip to database, I want to do in one go or in single Linq query
UserDataModel userObj = new UserDataModel()
{
Id = fakeUserID,
Name = "k1",
Surname = "z",
Email = "k.z#yahoo.co.uk",
Roles = new List<UserRoleDataModel>
{
new UserRoleDataModel {
UserId = fakeUserID,
RoleId = Context.Roles.Where(roleName => roleName.Name == RoleName).Select(x=>x.Id)
}
}
};
Context.Add<UserModel>(userObj);
Context.SaveChanges();
above code gives me error at RoleId
refer in screen shot;
Error because you are assigning IQueryable to a Property of type Int (I Assumed its Int). You should do this:
RoleId = Context.Roles.Where(roleName => roleName.Name == RoleName && roleName.Id==Id).Select(x=>x.Id).First();
Related
I've got the following container class:
public class AssetAndItsDepositsContainer
{
public jp_asset Asset { get; set; }
public jp_deposit Deposit { get; set; }
}
Is there a way to take the following LINQ query:
from a in serviceContext.jp_assetSet
join d in serviceContext.jp_depositsSet on a.Id equals d.jp_assetid.Id
where a.statecode == jp_assetState.Active &&
a.jp_isonhold = true
select new AssetAndItsDepositsContainer()
{
Asset = a,
Deposit = d
})
.ToList();
And "translate" it by using QueryExpression?
This is what I came up with so far, but I don't know how to mimic the select new expression:
QueryExpression query = new QueryExpression(jp_asset.EntityLogicalName);
query.ColumnSet = new ColumnSet(true);
query.Criteria.AddCondition("statecode", ConditionOperator.Equal, (int)jp_assetState.Active);
query.Criteria.AddCondition("jp_isonhold", ConditionOperator.Equal, true);
LinkEntity link = query.AddLink(jp_deposit.EntityLogicalName, "Id", "jp_assetid", JoinOperator.Inner);
// Now what?
var res = service.RetrieveMultiple(query).Entities; // gets only jp_assets
You can't access an entire LinkEntity, you can only access its attributes as AliasedValue properties on the main Entity itself.
I would simply retrieve the Id of the second record you're looking for as part of an EntityReference and then execute a Retrieve.
You can actually construct valid Entity objects from linked entities. The only requirement is that the primary key of the linked entity must be available in the result set.
So, your code snippet could be extended like this:
var query = new QueryExpression(jp_asset.EntityLogicalName);
query.ColumnSet.AllColumns = true;
query.Criteria.AddCondition("statecode", ConditionOperator.Equal, (int)jp_assetState.Active);
query.Criteria.AddCondition("jp_isonhold", ConditionOperator.Equal, true);
LinkEntity link = query.AddLink(jp_deposit.EntityLogicalName, "Id", "jp_assetid", JoinOperator.Inner);
link.EntityAlias = "d";
link.Columns.AddColumns("jp_depositid", "jp_name");
IEnumerable<Entity> deposits = Service.RetrieveMultiple(query).Entities
.Select(e => new Entity("jp_deposit")
{
Id = (Guid)e.GetAttributeValue<AliasedValue>("d.jp_depositid").Value,
["jp_name"] = e.GetAttributeValue<AliasedValue>("d.jp_name")?.Value
});
Note
The example above will only work reliable for inner joins. In the result set the primary key (ID) for the linked entity will always be available. Therefore it is safe to get its value using the .Value syntax. All other attribute values can be retrieved using ?.Value.
For left joins you would need to filter the result set first before performing the Select.
I Using Two Table User And Location In User Table I having LocationId And When I'm going to edit The User Form Then I need User With There Exact Location In Drop Down.but i didn't get that this is my code Of Controller:-
LogisticsEntities db = new LogisticsEntities();
RegisterModel Reg = new RegisterModel();
var tempUser = (from c in db.Users select new RegisterModel { _UserId = c.UserID, UserName = c.Name, Code = c.Code, Email = c.Email, Phone = c.Phone, JobRole = c.JobRole, StartDate = c.StartDate, EndDate = c.EndDate, LocationId = c.Location }).SingleOrDefault(x => x._UserId == id);
var varLocation = from Ls in db.Locations select Ls;
ViewData["LocationId"] = new SelectList(varLocation.ToList(), "LocationID", "Location1", "2");
if (tempUser != null)
return View(tempUser);
else
return View();
And In My View I Have code: -
#Html.DropDownList("LocationID", (SelectList)ViewData["LocationId"])
Thanx In Advance..
You are using LocationID as both first parameter of the dropdown and inside ViewData. In order to generate a dropdown you need 2 things: the first argument will be used to generate the name attribute of the dropdown and used to bind the value back and the second argument must represent a collection of SelectListItem that will be used to create the options of the dropdown. So try using a different key for the collection:
ViewData["locations"] = new SelectList(varLocation.ToList(), "LocationID", "Location1", "2");
and then:
#Html.DropDownList("LocationID", (SelectList)ViewData["locations"])
UPDATE: I essentially want to get a list of all permissions and a list of all permissions for a given role. I then want to mark each permission in a list of SelectListItems as selected when they already belong to the Role
I have three tables:
Project 1-* Role - Permission
I am trying to create and IEnumerable using projection that has all permissions in the list but when I project to SelectItemList it identifies the Permissions that are already associated with a particular role:
public IEnumerable GetAllPermissionsPLusRole(int projectid, int roleid)
{
using (var db = new Entities())
{
var permissions = (from p in db.Permissions
select p).ToList();
var permissionsForRole = from r in db.Roles
where r.RoleId == roleid && r.PrjectProjectId == contractid
select r.Permissions.ToList();
IEnumerable<SelectListItem> selectList = from p in permissions select new SelectListItem { Text = p.PermissionName, Value = p.PermissionId.ToString()};
return selectList;
}
}
What I want to do is have a conditional Selected in the projection so when I display the list I can show the permissions already associated to the Role.
Thanks in advance.
If I understand it right, you've already fetched all the data, now you just need to check if given permission is in the permissionsForRole list, i.e. like that:
IEnumerable<SelectListItem> selectList = from p in permissions
select new SelectListItem
{
Text = p.PermissionName,
Value = p.PermissionId.ToString(),
Selected = permissionsForRole.Contains(p)
};
So I'm new to linq so be warned what I'm doing may be completely stupid!
I've got a table of caseStudies and a table of Services with a many to many relasionship
the case studies already exist and I'm trying to insert a service whilst linking some case studies that already exist to it. I was presuming something like this would work?
Service service = new Service()
{
CreateDate = DateTime.Now,
CreatedBy = (from u in db.Users
where u.Id == userId
select u).Take(1).First(),
Description = description,
Title = title,
CaseStudies = (from c in db.CaseStudies
where c.Name == caseStudy
select c),
Icon = iconFile,
FeatureImageGroupId = imgGroupId,
UpdateDate = DateTime.Now,
UpdatedBy = (from u in db.Users
where u.Id == userId
select u).Take(1).First()
};
But This isn't correct as it complains about
Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Data.Objects.DataClasses.EntityCollection'
Can somebody please show me the correct way.
Thanks in advance
Yo have to add the query result to the case studies collection instead of trying to replace it.
var service = new Service { ... };
foreach (var caseStudy in db.CaseStudies.Where(s => s.Name == caseStudyName)
{
service.CaseStudies.Add(caseStudy);
}
You can wrap this in an extension method and get a nice syntax.
public static class ExtensionMethods
{
public static void AddRange<T>(this EntityCollection<T> entityCollection,
IEnumerable<T> entities)
{
// Add sanity checks here.
foreach (T entity in entities)
{
entityCollection.Add(entity);
}
}
}
And now you get the following.
var service = new Service { ... };
service.CaseStudies.AddRange(db.CaseStudies.Where(s => s.Name == caseStudyName));
I have a DataTable that queries out something like below
usergroupid...userid......username
1.............1...........John
1.............2...........Lisa
2.............3...........Nathan
3.............4...........Tim
What I'm trying to do is write a LINQ statement that will return an array of UserGroup instances. The UserGroup class has properties of UserGroupId and Users. Users is an array of User instances. The User class then has properties of UserId and UserName.
Can filling such a hierarchy be done with a single LINQ statement and what would it look like?
Thanks a million
Check this out, hope this helps
var users = new[]
{
new {UserGroupId = 1, UserId = 1, UserName = "John"},
new {UserGroupId = 1, UserId = 2, UserName = "Lisa"},
new {UserGroupId = 2, UserId = 3, UserName = "Nathan"},
new {UserGroupId = 3, UserId = 4, UserName = "Tim"}
};
var userGroups = from user in users
group user by user.UserGroupId into userGroup
select new {
UserGroupId = userGroup.Key,
Users = userGroup.ToList()
};
foreach (var group in userGroups)
{
Console.WriteLine("{0} - {1}",group.UserGroupId, group.Users.Count);
}
There is - look at GroupBy and Select methods.