I'm new to ASP.NET MVC, altough could call myself experinced programmer in web forms field.
I'm learning MVC now. Trying to add controller with Entity framework abolities.
Here is below code of model class:
Imports System.Data.Entity
Public Class Users
Public Property ID() As Integer
Public Property Login() As String
Public Property Password() As String
Public Property Avatar() As Image
Public Property Country() As Integer
Public Property City() As Integer
Public Property Phone() As String
Public Property Email() As String
Public Property Registered() As Date
End Class
Public Class StopSaleDBContext
Inherits DbContext
Public Property Users() As DbSet(Of Users)
End Class
When I'm adding controller I got error Unable retrieve metadata from ProjectName.Users Object reference not set to an instance of object.
Compile your project and try again.
Related
I'm trying to migrate an objectcontext/edmx system to dbcontext (EF6) with fluent mapping. I have a few instances like the following. Principal table has a relationship to a dependent table where a non-PK column in the dependent table holds the value of a PK column in the principal. On its own this would be a one to many relationship, but there is a unique index on the dependent table FK columns. Using EDMX mapping, this works fine as long as you define the relationship using mapping rather then referential constraints. Below is an executable example - you don't need the database because it doesn't get that far, currently:
Imports System.Data.Entity
Imports System.Data.Entity.ModelConfiguration
Module Module1
Sub Main()
Using session As New SaturnEntities
Dim res = session.BookingLegSet.Select(Function(x) New With {x.Prefix, x.ID, x.AddressDetails.Address}).ToList
End Using
End Sub
End Module
Partial Public Class BookingLeg
Public Property Prefix As String
Public Property ID As Integer
Public Property LegIndex As Integer
Public Overridable Property AddressDetails As BookingLegAddress
End Class
Partial Public Class BookingLegAddress
Public Property Prefix As String
Public Property ID As Integer
Public Property Address As String
Public Overridable Property BookingLeg As BookingLeg
Property JobLegPrefix As String
Property JobLegID As Integer?
End Class
Public Class BookingLegConfig
Inherits EntityTypeConfiguration(Of BookingLeg)
Public Sub New()
ToTable("JobLegs", "dbo")
HasKey(Function(x) New With {x.Prefix, x.ID})
HasOptional(Function(x) x.AddressDetails).WithRequired(Function(x) x.BookingLeg).Map(Function(x) x.MapKey("Prefix", "ID"))
End Sub
End Class
Public Class BookingLegAddressConfig
Inherits EntityTypeConfiguration(Of BookingLegAddress)
Public Sub New()
ToTable("JobAddresses", "dbo")
HasKey(Function(x) New With {x.Prefix, x.ID})
HasRequired(Function(x) x.BookingLeg).WithOptional(Function(x) x.AddressDetails).Map(Function(x) x.MapKey("JobLegPrefix", "JobLegID"))
End Sub
End Class
Partial Public Class SaturnEntities
Inherits DbContext
Public Sub New()
MyBase.New("data source=dbSaturn;initial catalog=Saturn;integrated security=True;MultipleActiveResultSets=True;")
End Sub
Protected Overrides Sub OnModelCreating(modelBuilder As DbModelBuilder)
modelBuilder.Configurations.Add(New BookingLegConfig)
modelBuilder.Configurations.Add(New BookingLegAddressConfig)
End Sub
Public Overridable Property BookingLegAddressSet() As DbSet(Of BookingLegAddress)
Public Overridable Property BookingLegSet() As DbSet(Of BookingLeg)
End Class
BookingLeg is the principal entity and BookingLegAddress is the dependant. JobLegPrefix and JobLegID in the dependent will be either null or will hold the Prefix and ID values from a BookingLeg record. When you run this you get an error that AddressDetails has been configured with conflicting mapping information. I've tried numerous different ways to map this, but haven't got anywhere - can anyone tell me what I need to do?
Remove the
HasOptional(Function(x) x.AddressDetails).WithRequired(Function(x) x.BookingLeg).Map(Function(x) x.MapKey("Prefix", "ID"))
line from BookingLegConfig class. Every single relationships must be configured only once in a single place (part of the configuration of any of the two involved entities, but not in both). In this particular case you should keep the second configuration inside BookingLegAddressConfig class
HasRequired(Function(x) x.BookingLeg).WithOptional(Function(x) x.AddressDetails).Map(Function(x) x.MapKey("JobLegPrefix", "JobLegID"))
because it specifies the correct FK column names.
Also EF6 does not support explicit FK columns for this type of relationship - no HasForeignKey fluent API, and MapKey is for specifying shadow property (and column) names. So additionally remove the JobLegPrefix and JobLegID properties from the BookingLegAddress class:
Partial Public Class BookingLegAddress
Public Property Prefix As String
Public Property ID As Integer
Public Property Address As String
Public Overridable Property BookingLeg As BookingLeg
End Class
I'm trying to simply access information in a existing database using vb.net MVC. The issue is, when i run the code, it creates a table in the database, with a name similar to the table I'm attempting to access with an 's' appended on the end.
e.g:
Existing table: VXPartsData.
Table created after running application: VXPartsDatas
I've managed to do this in c sharp quite easily, but don't understand where I'm going wrong using VB. If someone could please point me in the right direction, thanks
Imports System.Data.Linq
Imports System.Data.Linq.Mapping
Imports System.ComponentModel.DataAnnotations
Imports System.Data.Entity
Namespace Models
<Table(Name:="dbo.VXPartsData")>
Public Class VXPartsData
<Key()>
Public Property PartNo As String
Public Property CustPart As String
Public Property ShortDesc As String
Public Property Part As String
Public Property Price As Decimal
Public Property DiscCode As String
Public Property Kit As Boolean
Public Property VXCODE As String
End Class
Public Class ProductContext
Inherits DbContext
Public Property VXPartsDatas As DbSet(Of VXPartsData)
End Class
End Namespace
Controller:
Imports System.Data.Entity
Imports Videx_PB2.Models
Public Class HomeController
Inherits System.Web.Mvc.Controller
Private db As New ProductContext
Function Index() As ActionResult
Return View(db.VXPartsDatas.ToList())
End Function
End Class
Connection String:
<connectionStrings>
<add name="ProductContext" connectionString="server=(localdb)\MSSQLLocalDB; database=VidexPB; integrated security=SSPI" providerName="System.Data.sqlClient" />
</connectionStrings>
In your ProductContext class, add the following code:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
...
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
...
base.OnModelCreating(modelBuilder);
}
EF will not pluralize table names
I have been working with MVC 4 and Entity Framework to create a web app recently. Things have been going well with my database "ppProject" model, as shown here:
Public Class ppProject
<Key()>
Public Property ProjectID As Integer
Public Property ClientID As Integer
Public Property ProjectTitle As String
Public Overridable Property Client As ppClient
Public Overridable Property Milestones As ICollection(Of ppMilestone)
Public Overridable Property Tasks As ICollection(Of ppTask)
End Class
The problem is that I am adding a new table of employees, "ppEmployees". This way the Project can have a ProjectManager, which is a foreign key into the Employees table. These are the new models where ProjectManagerID (foreign key) is linked to EmployeeID (primary key):
Public Class ppProject
<Key()>
Public Property ProjectID As Integer
Public Property ClientID As Integer
Public Property ProjectTitle As String
Public Property ProjectManagerID As Integer 'NEW'
Public Overridable Property Client As ppClient
Public Overridable Property Milestones As ICollection(Of ppMilestone)
Public Overridable Property Tasks As ICollection(Of ppTask)
Public Overridable Property ProjectManager As ppEmployee 'NEW'
End Class
Public Class ppEmployee
<Key()>
Public Property EmployeeID As Integer
Public Property DepartmentID As Integer
Public Property FirstName As String
Public Property LastName As String
Public Overridable Property ProjectsInManagement As ICollection(Of ppProject)
Public Overridable Property TimeItems As ICollection(Of ppTimeItem)
Public Overridable Property Department As ppDepartment
End Class
When I change my project model and add the employee model, I am getting the error
Invalid column name 'ProjectManager_EmployeeID'
The line of code that is triggering this is when I first access my projects in a view with:
#For Each proj In client.Projects
Any ideas at what is causing this? This must be a naming convention problem or something simple because I haven't had any errors with any of my other table models prior to this.
EDIT - See my answer below. Very confused about what Entity Framework is doing here.
In Entity Framework the name of the field must match the name of the column.
otherwise EF wouldnt know how to map the fields unless you decorate the property with the column attribute like you did in your answer.
Ok I think I've fixed this. I had to make the following changes to the "ppProject" class:
<Column("ProjectManagerID")>
Public Property EmployeeID As Nullable(Of Integer) 'Has to be set, dont know why
If anyone knows why my property has to be named EmployeeID, please let me know. I'm very curious.
I had a similar problem about a month ago. I dropped the table and created a new one and the problem was solved. that is after i have tried other ways that did not work
I am complete beginner with ASP.net and VB.net, I created two classes one for Teams and another for Fixtures which will take in 2 teams.
Imports System.Data.Entity
Public Class Team
Public Property ID() As Integer
Public Property Name() As String
Public Property Points() As Integer
End Class
Public Class TeamDBContext
Inherits DbContext
Public Property Teams() As DbSet(Of Team)
End Class
Imports System.Data.Entity
Public Class Fixture
Public Property ID() As Integer
Public Property Week() As Integer
Public Property HomeTeam() As Team
Public Property AwayTeam() As Team
End Class
Public Class FixtureDBContext
Inherits DbContext
Public Property Fixtures() As DbSet(Of Fixture)
End Class
I created a FixturesController with the read/write actions and views. However when I go to create a Fixture in my application I only see a field for Week and not field for HomeTeam or AwayTeam.
Well you need to add them manually. Brad Wilson wrote a nice article explaining in details how you could make the templated helpers to recursively descend in your nested models.
Also as a side remark you probably don't need 2 db contexts, one should be enough and it could contain both your Teams and Fixtures:
Public Class FixtureDBContext
Inherits DbContext
Public Property Teams() As DbSet(Of Team)
Public Property Fixtures() As DbSet(Of Fixture)
End Class
OK, I have a problem where the ModelState errors are not mapping to the correct properties.
Let me see if I can explain this.
I have a ViewModel like so:
public class MyViewModel
{
public string Prop1 {get;set;}
public string Prop2 {get;set;}
....
}
In my view, I have a model that has a collection of this type which I have an EditorTemplate for. So it generates MyViewModels[0].Prop1, MyViewModels[1].Prop1, etc.
Problem is, when I set the error on the ModelState in my service layer via an interface I have made called IValidationDictionary which has a wrapper around model state, it does not attach the error to the correct row in the view, rather to the end of the model as Prop1.
EDIT
Here is the ModelStateWrapper (VB - Sorry!)
Public Class ModelStateWrapper
Implements IValidationDictionary
#Region "Private Members/Properties"
Private modelState As ModelStateDictionary
Public ReadOnly Property IsValid As Boolean Implements IValidationDictionary.IsValid
Get
Return modelState.IsValid
End Get
End Property
#End Region
#Region "Constructor(s)"
Public Sub New(modelState As ModelStateDictionary)
Me.modelState = modelState
End Sub
#End Region
#Region "Methods"
Public Sub AddError(key As String, message As String) Implements IValidationDictionary.AddError
modelState.AddModelError(key, message)
End Sub
#End Region
End Class
Sounds like you may be using Dependency Injection and injecting the ModelStateDictionary into your ModelStateWrapper class, which is again injected into your Service Layer?
I can only guess whatever is getting injected is not using the Controller class ModelState property (ModelStateDictionary) of your current HTTP request.
Are you by any chance initializing a new instance of ModelStateDictionary and passing it into your ModelStateWrapper?
If you are using Dependency Injection, please show me your Injection configuration so I can give you a better answer.