I am working on a CRUD ASP.NET Razor Pages app that allows a user to search continents, countries, and add and remote data about them. I am getting the following error about the index model for the index page:
Error CS1061 'IndexModel' does not contain a definition for 'SearchString' and no accessible extension method 'SearchString' accepting a first argument of type 'IndexModel' could be found (are you missing a using directive or an assembly reference?)
public List<Country> Countries { get; set; }
public async Task OnGetAsync()
{
var countries = from c in _context.Countries
select c;
if (!string.IsNullOrEmpty(SearchString))
{
countries = countries.Where(c => c.Name.Contains(SearchString));
}
Countries = await countries.ToListAsync();
}
public async Task<IActionResult> OnPostAsync(string id)
{
if (id == null)
{
return NotFound();
}
Country Country = await _context.Countries.FindAsync(id);
if (Country != null)
{
_context.Countries.Remove(Country);
}
await _context.SaveChangesAsync();
return RedirectToPage("./Index");
}
[BindProperty(SupportsGet = true)]
public string SearchString { get; set; }
} ```
Can someone point out to me why I am getting the error?
Thank you
Found the issue, I should've used the following using directive:
#using RazorCountry.Pages.Countries
Related
Hello Everyone im missing something fairly fundamental here and i could really appreciate some guidance .
I am fairly new to Blazor and the entity framework and am building one of my first Blazor apps
I have a fairly basic data class
using System.ComponentModel.DataAnnotations;
namespace BIDM2.Data
{
public class InvalidAddressMapping
{
[Key]
public int record_no { get; set; } = 0;
public string sales_org_pos { get; set; } = " ";
public string press_sales_mgr_code { get; set; } = " ";
public string press_sales_mgr_Name { get; set; } = " ";
public string forming_sales_rep_code { get; set; } = " ";
public string forming_sales_rep_Name { get; set; } = " ";
}
}
that i am using in my controller as follows
[HttpGet]
public async Task <ActionResult<List<InvalidAddressMapping>>> GetInvalidAdressMappings()
{
return await _db.GetInvalidAddressMappings.FromSqlRaw("EXEC BIDM_GetInvalidAddressMappings;").ToListAsync();
}
and im trying to use it in my razor page like this
#code {
List<InvalidAddressMapping> invalidMappings = new List<InvalidAddressMapping>();
protected override async Task OnInitializedAsync()
{
invalidMappings = await HttpClient.GetFromJsonAsync<List<InvalidAddressMapping>>(NavigationManager.BaseUri + "invalidmapping");
}
}
how ever when i try and run my razor page im getting an error CS8601 Possible null Reference asignment :(
Im not sure i totaly understand and i could use some guidance to point me in the right direction it has to be somethign fairly fundamental i am missing
interestingly this all came about because im trying to convert an existing non async method to an async method
when i use
//1. get invalid address mappings
public InvalidAddressMapping[] GetInvalidAddressMappings()
{
InvalidAddressMapping[] invMappings;
// exec BIDM_GetInvalidAddressMappings calls the stored procedure
invMappings = _dbcontext.GetInvalidAddressMappings.FromSqlRaw("EXEC BIDM_GetInvalidAddressMappings;").ToArray();
return invMappings;
}
}
it works beautifully and i can see a lovely list of JSON data
please help a struggling old git out and pint me in a direction where i can understand where i am going wrong :)
thank you every one
The GetFromJsonAsync extension method returns a nullable type. In your case, it is List<InvalidAddressMapping>? (note the extra ? on the end there). If it fails to deserialise properly, for example, it could return null. The code is telling you that you need to check for a null response to be safe.
So the safe version is to do something like this:
var result = await HttpClient.GetFromJsonAsync<List<InvalidAddressMapping>>(
NavigationManager.BaseUri + "invalidmapping");
if(result == null)
{
// Do something here to handle this error, for example:
throw new Exception("Can't get data from the server for some reason, help!");
}
invalidMappings = result;
Also note that the CS8601 message you see is a warning, not an error. So technically you could ignore it, though I would strongly advise against doing that.
I'm using the latest version of ABP from abp.io and have two entities with a many-many relationship. These are:
public class GroupDto : AuditedEntityDto<Guid>
{
public GroupDto()
{
this.Students = new HashSet<Students.StudentDto>();
}
public string Name { get; set; }
public bool IsActive { get; set; }
public virtual ICollection<Students.StudentDto> Students { get; set; }
}
and
public class StudentDto : AuditedEntityDto<Guid>
{
public StudentDto()
{
this.Groups = new HashSet<Groups.GroupDto>();
}
public string Name { get; set; }
public bool IsActive { get; set; }
public virtual ICollection<Groups.GroupDto> Groups { get; set; }
}
I set up the following test to check that I am retrieving the related entities, and unfortunately the Students property is always empty.
public async Task Should_Get_List_Of_Groups()
{
//Act
var result = await _groupAppService.GetListAsync(
new PagedAndSortedResultRequestDto()
);
//Assert
result.TotalCount.ShouldBeGreaterThan(0);
result.Items.ShouldContain(g => g.Name == "13Ck" && g.Students.Any(s => s.Name == "Michael Studentman"));
}
The same is true of the equivalent test for a List of Students, the Groups property is always empty.
I found one single related answer for abp.io (which is not the same as ABP, it's a newer/different framework) https://stackoverflow.com/a/62913782/7801941 but unfortunately when I add an equivalent to my StudentAppService I get the error -
CS1061 'IRepository<Student, Guid>' does not contain a definition for
'Include' and no accessible extension method 'Include' accepting a
first argument of type 'IRepository<Student, Guid>' could be found
(are you missing a using directive or an assembly reference?)
The code for this is below, and the error is being thrown on the line that begins .Include
public class StudentAppService :
CrudAppService<
Student, //The Student entity
StudentDto, //Used to show students
Guid, //Primary key of the student entity
PagedAndSortedResultRequestDto, //Used for paging/sorting
CreateUpdateStudentDto>, //Used to create/update a student
IStudentAppService //implement the IStudentAppService
{
private readonly IRepository<Students.Student, Guid> _studentRepository;
public StudentAppService(IRepository<Student, Guid> repository)
: base(repository)
{
_studentRepository = repository;
}
protected override IQueryable<Student> CreateFilteredQuery(PagedAndSortedResultRequestDto input)
{
return _studentRepository
.Include(s => s.Groups);
}
}
This implements this interface
public interface IStudentAppService :
ICrudAppService< // Defines CRUD methods
StudentDto, // Used to show students
Guid, // Primary key of the student entity
PagedAndSortedResultRequestDto, // Used for paging/sorting
CreateUpdateStudentDto> // Used to create/update a student
{
//
}
Can anyone shed any light on how I should be accessing the related entities using the AppServices?
Edit: Thank you to those who have responded. To clarify, I am looking for a solution/explanation for how to access entities that have a many-many relationship using the AppService, not the repository.
To aid with this, I have uploaded a zip file of my whole source code, along with many of the changes I've tried in order to get this to work, here.
You can lazy load, eagerly load or configure default behaviour for the entity for sub-collections.
Default configuration:
Configure<AbpEntityOptions>(options =>
{
options.Entity<Student>(studentOptions =>
{
studentOptions.DefaultWithDetailsFunc = query => query.Include(o => o.Groups);
});
});
Eager Load:
//Get a IQueryable<T> by including sub collections
var queryable = await _studentRepository.WithDetailsAsync(x => x.Groups);
//Apply additional LINQ extension methods
var query = queryable.Where(x => x.Id == id);
//Execute the query and get the result
var student = await AsyncExecuter.FirstOrDefaultAsync(query);
Or Lazy Load:
var student = await _studentRepository.GetAsync(id, includeDetails: false);
//student.Groups is empty on this stage
await _studentRepository.EnsureCollectionLoadedAsync(student, x => x.Groups);
//student.Groups is filled now
You can check docs for more information.
Edit:
You may have forgotten to add default repositories like:
services.AddAbpDbContext<MyDbContext>(options =>
{
options.AddDefaultRepositories();
});
Though I would like to suggest you to use custom repositories like
IStudentRepository:IRepository<Student,Guid>
So that you can scale your repository much better.
Sorry, another multi tenancy post. I can't find a good solution to site, I have read tons of great posts on multi tenancy for ASP MVC but I still need some good advice.
I have an ASP MVC Entity Framework 6 Code First web application. This app has to work for many different clients using a single database for all of them.
I have an entity for all the clients, and each client can have different hosts.
public class Client
{
public int ClientId { get; set; }
public string Name { get; set; }
...
public ICollection<ClientHost> Hosts { get; set; }
}
public class ClientHost
{
public int ClientId { get; set; }
public Client Client { get; set; }
public string Name { get; set; }
}
I have added a column "ClientId" to all the entities I need to filter, so I can separate data from different clients.
public class SomeEntity
{
public int Id { get; set; }
...
public int ClientId { get; set; }
}
First thing I need is, base on the host, retrieve the ClientId to work with.
private static int GetClientId()
{
var currentClient = Convert.ToInt32(HttpRuntime.Cache[CacheClient]);
if (currentClient != null) return currentClient;
lock (Synclock)
{
using (var dataContext = new MyDataContext())
{
var urlHost = HttpContext.Current.Request.Url.Host;
currentClient = dataContext.Clients
.FirstOrDefault(p => p.Hosts.Any(h => h.Name == urlHost));
if (currentClient == null) return null;
HttpRuntime.Cache.Insert(CacheClient, currentClient, null, Cache.NoAbsoluteExpiration, TimeSpan.FromSeconds(0), CacheItemPriority.Default, null);
return currentClient;
}
}
}
QUESTION 1
As you see I get the clientId from DB and store it in cache, so I don't have to call DB every time I need it.
I don't know if there is a better approach to get the client Id or, better, to store it.
EDIT
After investigation I have created a variable in DbCOntext and initialize it in the Startup.cs file.
public class MyDataContext : IdentityDbContext<ApplicationUser, CustomRole, int, CustomUserLogin, CustomUserRole, CustomUserClaim>
{
public static string ClientId { get; set; }
public MyDataContext() : base("MyDataBase") { }
public static MyDataContext Create()
{
return new myDataContext();
}
....
}
In Startup.cs
public partial class Startup
{
public void Configuration(IAppBuilder app)
{
MyDataContext.ClientId = ClientConfiguration.GetCurrentClientId();
ConfigureAuth(app);
}
}
QUESTION 2
Once I have the ClientId, I need to add a filter to every query that needs it. Doing this manually can take you to make many errors or forget to do it in some places.
I need a way that the application can add the filter to all queries automatically (only those entities that need it), so I don't have to worry about a client getting other client's data. Also I need to add the ClientId to all the Insert and Update commands.
I have read about filtering and/or use EF Interceptors, but after reading some posts about that I can't figure out how to do it. Need some help here.
Thanks in advance.
EDIT
In order to solve QUESTION 2 I have followed this great post by Xabikos:
http://xabikos.com/2014/11/17/Create-a-multitenant-application-with-Entity-Framework-Code-First-Part-1/
I have changed it a little bit, since I don't use Users to get the current tenant and instead I use the host. This is part of the program I don't know yet how I'm going to solve but, assuming I already have the ClientId I can add filters to all the queries without realizing that is happening:
I have replaced all the user logic:
private static void SetTenantParameterValue(DbCommand command)
{
if (MyDataContext.ClientId == 0) return;
foreach (DbParameter param in command.Parameters)
{
if (param.ParameterName != TenantAwareAttribute.TenantIdFilterParameterName)
continue;
param.Value = MyDataContext.ClientId;
}
}
Same in all the places...
Than I only have to mark the entities that have to filter with TenantAware, indicating the property. In this case I do in my base class and then apply that base class to all the entities I need.
[TenantAware("ClientId")]
public abstract class ClientEntity : Entity, IClientEntity
{
public int ClientId { get; set; }
public Client Client { get; set; }
}
Here are a couple of things I have done in the past that might help.
Question 1:
I am not a big fan of session as the web is supposed to be stateless. However, it is sometimes necessary. Your approach is reasonable. You could also use cookies as well. What I use are Json Web Tokens (JWT) via my authentication provider (Auth0.com). For each request as it is authenticated, I look for this client id. Here is an example. This is MVC 6 as well. You could do the same type of things w/ cookies.
public class Auth0ClaimsTransformer : IClaimsTransformer
{
private string _accountId = AdminClaimType.AccountId.DefaultValue;
private string _clientId = AdminClaimType.ClientId.DefaultValue;
private string _isActive = AdminClaimType.IsActive.DefaultValue;
public Task<ClaimsPrincipal> TransformAsync(ClaimsTransformationContext context)
{
foreach (var claim in context.Principal.Claims)
{
switch (claim.Type)
{
case "accountId":
_accountId = claim.Value ?? _accountId;
break;
case "clientId":
_clientId = claim.Value ?? _clientId;
break;
case "isActive":
_isActive = claim.Value ?? _isActive;
break;
}
}
((ClaimsIdentity)context.Principal.Identity)
.AddClaims(new Claim[]
{
new Claim(AdminClaimType.AccountId.DisplayName, _accountId),
new Claim(AdminClaimType.ClientId.DisplayName, _clientId),
new Claim(AdminClaimType.IsActive.DisplayName, _isActive)
});
return Task.FromResult(context.Principal);
}
Then in my Startup.cs Configure method I plug in my claims transformer.
app.UseJwtBearerAuthentication(options);
app.UseClaimsTransformation(new ClaimsTransformationOptions
{
Transformer = new Auth0ClaimsTransformer()
});
Next I use a base authentication controller that parses out my claims into properties I can use in my controller.
[Authorize]
[Route("api/admin/[controller]")]
public class BaseAdminController : Controller
{
private long _accountId;
private long _clientId;
private bool _isActive;
protected long AccountId
{
get
{
var claim = GetClaim(AdminClaimType.AccountId);
if (claim == null)
return 0;
long.TryParse(claim.Value, out _accountId);
return _accountId;
}
}
public long ClientId
{
get
{
var claim = GetClaim(AdminClaimType.ClientId);
if (claim == null)
return 0;
long.TryParse(claim.Value, out _clientId);
return _clientId;
}
}
public bool IsActive
{
get
{
var claim = GetClaim(AdminClaimType.IsActive);
if (claim == null)
return false;
bool.TryParse(claim.Value, out _isActive);
return _isActive;
}
}
public string Auth0UserId
{
get
{
var claim = User.Claims.FirstOrDefault(x => x.Type == ClaimTypes.NameIdentifier);
return claim == null ? string.Empty : claim.Value;
}
}
private Claim GetClaim(AdminClaimType claim)
{
return User.Claims.FirstOrDefault(x => x.Type == claim.DisplayName);
}
Finally in my controller it is trivial to extract which tenant is making the call. e.g.
public FooController : BaseController
{
public async Task<IActionResult> Get(int id)
{
var foo = await _fooService.GetMultiTenantFoo(ClientId, id);
return Ok(foo);
}
}
Question 2:
One of the ways I have used in the past is create a BaseMultiTenant class.
public class BaseMultiTenant
{
public int ClientId {get;set;}
public virtual Client Client {get;set;}//if you are using EF
}
public class ClientHost : BaseMultiTenant
{
public string Name {get;set;}
//etc
}
Then simply create an extension method for multi-tenant based entities. I know this doesn't "do it automatically" but it is an easy way to ensure each multi-tenant entity is being called only by its owner.
public static IQueryable<T> WhereMultiTenant<T>(this IQueryable<T> entity, int clientId, Expression<Func<T, bool>> predicate)
where T : BaseMultiTenant
{
return entity.Where(x => x.ClientId == clientId)
.Where(predicate);
}
Then when someone calls for their resource you can:
var clientHost = _myContext.ClientHosts
.WhereMultiTenant(ClientId,
x => x.Name == "foo")
.FirstOrDefault();
Hope this is helpful.
Also found a similar example using an interface.
the Get(string _date) method below does not work. I get the following exception. I know EFCore is very limited but this exception does not help to see where the problem is exactly at. Can you please explain me what's causing this exception?
An unhandled exception occurred while processing the request.
ArgumentException: The given expression 'new EntryViewModel([x])' does not contain the searched expression '[x]' in a nested NewExpression with member assignments or a MemberBindingExpression.
Parameter name: fullExpression
InvokeMethod
TargetInvocationException: Exception has been thrown by the target of an invocation.
InvokeMethod
EntryController.cs
[HttpGet("{_date}")]
public async Task<IEnumerable<EntryViewModel>> Get(string _date)
{
DateTime date = DateTime.ParseExact(_date, "dd-MM-yyyy", CultureInfo.InvariantCulture);
User user = await _userManager.GetUserAsync(HttpContext.User);
var Entries = _context.Entries.Include(x => x.Budget)
.Where(x => x.User.Id == user.Id && x.Date >= date && x.Date < date.AddDays(7))
.Select(x=> new EntryViewModel(x))
.ToList();
return Entries;
}
EntryViewModel.cs
public class EntryViewModel
{
public int Id { get; set; }
public int BudgetId { get; set; }
public string Date { get; set; }
public int Duration { get; set; }
public string UserId { get; set; }
public EntryViewModel(Entry entry)
{
Id = entry.Id;
BudgetId = entry.BudgetId;
Date = entry.Date.ToString("dd-MM-yyyy", CultureInfo.InvariantCulture);
Duration = entry.Duration;
UserId = entry.UserId;
}
}
What this cryptic exception message is saying is that in EF, if you want to use x to construct a new object, it must be in the form new C { A = x.B, ... } (where C may be omitted to project to an anonymous type). EF does not support calling arbitrary functions (including constructors), only some specific functionality such as calling property setters is supported.
You can try as shown below then and let us know about the result.
var Entries = _context.Entries.Include(x => x.Budget)
.Where(x => x.User.Id == user.Id && x.Date >= date && x.Date < date.AddDays(7))
.Select(e=> new EntryViewModel
{
BudgetId=e.BudgetId,
Duration=e.Duration,
}).ToList();
Try adding AsNoTracking() to your query if you have no write
I'm a newbie with Entity Framework, and I have looked at the questions with the same title, but I haven't found a satisfying answer yet.
Here is my class:
public class MyUser
{
public string FirstName { get; set; }
public virtual ICollection<ProfileSkillEdu> Skills { get; set; }
}
And in the controller I have:
[HttpPost]
public ActionResult EditProfile(MyUser user, string emailAddress)
{
try
{
if (ModelState.IsValid)
{
_unitOfWork.GetMyUserRepository().Update(user);
_unitOfWork.Save();
return View(user);
}
}
catch (DataException)
{
//Log the error
ModelState.AddModelError("", "Unable to save changes. Try again, and if the problem persists see your system administrator.");
}
return View(user);
}
In my user repository:
public virtual void Update(TEntity entityToUpdate)
{
dbSet.Attach(entityToUpdate);
context.Entry(entityToUpdate).State = EntityState.Modified;
}
I keep getting An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key. at dbSet.Attach(entityToUpdate). I watched the variables and I found that if MyUser has only 1 Skill object, it's fine because when it does Attach, the key is unique (value is 0). But if MyUser has 2 skill objects, both primary key have the value of 0 and therefore the error.
Can someone explain why all the Skill object's primary key have the values of 0? Also, is there a simple solution to this problem? I thought it's supposed to be straight forward but I have been struggling with this for hours.
Edit:
I wonder if the problem is because of how I use the context.
In the controller definition I have:
public class MyAccountController : Controller
{
IUnitOfWork _unitOfWork;
public ActionResult EditProfile()
{
if (_user == null)
{
MembershipUser currentUser = Membership.GetUser();
if (currentUser == null)
{
return RedirectToAction("Logon", "Account");
}
Guid currentUserId = (Guid)currentUser.ProviderUserKey;
MyUserService svc = new MyUserService();
MyUser user = svc.GetUserLoaded(currentUserId); //this uses include/eager loading to get the Skills too.
if (user == null)
{
return RedirectToAction("Logon", "Account");
}
else
_user = user;
}
return View(_user);
}
}
In my UnitOfWork I have:
public class UnitOfWork:IUnitOfWork
{
private GlobalContext context = new GlobalContext();
private GenericRepository<MyUser> myUserRepository;
private GenericRepository<Skill> skillRepository;
.. and implementation of Save() and Dispose()
}