Error: the entity type requires a primary key
I would like to expand the question asked on this thread
Binding listbox to observablecollection
by giving it an ability to persistent the data. The structure is mostly the same except I installed Entity Framework Core, created a DbContext class to hold the records. I added a button to save the dataset to SQL Server. I did not encounter the compiling error but when I attempted to save the data in the database I got this run time exception:
Message=The entity type 'Fruit' requires a primary key to be defined.
The whole exception in its entirety is listed below
System.InvalidOperationException was unhandled HResult=-2146233079 Message=The entity type 'Fruit' requires a primary key to be defined. Source=Microsoft.EntityFrameworkCore StackTrace: at Microsoft.EntityFrameworkCore.Internal.ModelValidator.ShowError(String message) at Microsoft.EntityFrameworkCore.Internal.ModelValidator.EnsureNonNullPrimaryKeys(IModel model) at Microsoft.EntityFrameworkCore.Internal.ModelValidator.Validate(IModel model) at Microsoft.EntityFrameworkCore.Internal.RelationalModelValidator.Validate(IModel model) at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator) at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.<>c__DisplayClass14_0.b__0(Object k) at System.Collections.Concurrent.ConcurrentDictionary2.GetOrAdd(TKey key, Func2 valueFactory) at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator) at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel() at Microsoft.EntityFrameworkCore.Internal.LazyRef1.get_Value() at Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model() at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServiceCollectionExtensions.<>c.
This is the updated class Fruit:
namespace Fruits.ViewModels
{
[Table("Fruits")]
public class Fruit : ViewModelBase
{
#region Constractor
public Fruit()
{
}
public Fruit(string name, String clrString)
{
FruitName = name;
// Parse colors like so: (Color)ColorConverter.ConvertFromString(clrString);
FruitColor = clrString;
_id = Guid.NewGuid();
}
public Fruit(string name, Color clr)
{
FruitName = name;
FruitColor = clr.ToString();
_id = Guid.NewGuid();
}
#endregion
#region Properties
private Guid _id;
[Key]
public Guid ID
{
get { return _id; }
}
#region FruitName
private string _fruitname;
public string FruitName
{
get
{
return _fruitname;
}
set
{
if (_fruitname != value)
{
_fruitname = value;
OnPropertyChanged("FruitName");
}
}
}
#endregion
#region FruitColor
private String _fruitcolor;
public String FruitColor
{
get
{
return _fruitcolor;
}
set
{
if (_fruitcolor != value)
{
_fruitcolor = value;
OnPropertyChanged("FruitColor");
}
}
}
#endregion
#region Selected Property
private bool _isSelected = true;
// NOTE: I renamed this property
public bool IsSelected
{
get
{
return _isSelected;
}
set
{
if (_isSelected != value)
{
_isSelected = value;
OnPropertyChanged("IsSelected");
}
}
}
#endregion
#endregion
}
}
The updated MainWindows xaml (to add a save button)
<Window x:Class="Fruits.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:Fruits"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<RoutedCommand x:Key="AddFruit" />
<RoutedCommand x:Key='SaveFruit' />
</Window.Resources>
<Window.CommandBindings>
<CommandBinding Command='{StaticResource AddFruit}'
Executed='AddFruitCommandBinding_Executed'
CanExecute='AddFruitCommandBinding_CanExecute' />
<CommandBinding Command='{StaticResource SaveFruit}'
Executed='SaveFruitCommandBinding_Executed'
CanExecute='SaveFruitCommandBinding_CanExecute' />
</Window.CommandBindings>
<Grid>
<StackPanel Orientation='Vertical'
Margin='10'>
<CheckBox IsChecked="{Binding ShowSelectedFruitOnly}">Selected Fruit Only</CheckBox>
<ListBox x:Name='MyList'
ItemsSource="{Binding FruitsView}"
ItemTemplate='{StaticResource FruitTemp}' />
<StackPanel Orientation="Horizontal"
Margin="0,10,0,0">
<Label Width="100">New Name:</Label>
<TextBox Width="200"
Text="{Binding NewFruitName, Mode=TwoWay }"
/>
</StackPanel>
<StackPanel Orientation="Horizontal"
Margin="0,10,0,0">
<Label Width="100">New Color:</Label>
<!--<TextBox Width="200"
Text="{Binding NewFruitColor, UpdateSourceTrigger=PropertyChanged}" />-->
<TextBox Width="200"
Text="{Binding NewFruitColor, Mode=TwoWay }" />
<ContentControl Style="{StaticResource ColorSwatch}"
Margin="2"
VerticalAlignment="Center"
Content="{Binding NewFruitColor}" />
</StackPanel>
<StackPanel Orientation='Horizontal'>
<Button x:Name='AddFruit'
Height='auto'
Width='auto'
Content='Add New Fruit 2'
Margin='0,10,0,0'
Command='{StaticResource AddFruit}' />
<Button x:Name='SaveFruit'
Height='auto'
Width='auto'
Content='Save Fruit'
Margin='100,10,0,0'
Command='{StaticResource SaveFruit}' />
</StackPanel>
</StackPanel>
</Grid>
</Window>
and my code behind the mainwindows (added handler)
using Fruits.ViewModels;
using System;
using System.Windows;
using System.Windows.Input;
namespace Fruits
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
ViewModel.AddNewFruit("Jackfruit", "Yellow");
ViewModel.AddNewFruit("Watermelon", "ForestGreen");
ViewModel.AddNewFruit("Apple", "Red");
ViewModel.AddNewFruit("Banana", "Yellow");
ViewModel.AddNewFruit("Orange", "DeepSkyBlue");
//ViewModel.Fruits[0].IsSelected = false;
//ViewModel.Fruits[1].IsSelected = false;
ViewModel.FruitsView.Refresh();
}
public MainViewModel ViewModel { get { return DataContext as MainViewModel; } }
private void AddFruitCommandBinding_Executed(object sender, ExecutedRoutedEventArgs e)
{
ViewModel.AddNewFruit();
}
private void AddFruitCommandBinding_CanExecute(object sender, CanExecuteRoutedEventArgs e)
{
e.CanExecute =
ViewModel != null
&& !String.IsNullOrWhiteSpace(ViewModel.NewFruitName)
&& !String.IsNullOrWhiteSpace(ViewModel.NewFruitColor)
;
}
private void SaveFruitCommandBinding_Executed(object sender, ExecutedRoutedEventArgs e)
{
using (var db=new FruitDbContext())
{
db.SaveChanges();
}
}
private void SaveFruitCommandBinding_CanExecute(object sender, CanExecuteRoutedEventArgs e)
{
e.CanExecute = true;
}
}
}
My newly added dbContext:
namespace Fruits.ViewModels
{
public class FruitDbContext:DbContext
{
public DbSet<Fruit> Fruits { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionBuilder)
{
optionBuilder.UseSqlServer(@"Server = xxx; Database=Test; Integrated Security = True");
}
}
}
Other classes remain unchanged, but I listed them anyway:
ViewModelBase
namespace Fruits.ViewModels
{
public class ViewModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string name)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}
}
}
ViewModel
using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows.Data;
using System.Windows.Media;
namespace Fruits.ViewModels
{
#region MainViewModel Class
public class MainViewModel : ViewModelBase
{
public MainViewModel()
{
Fruits = new ObservableCollection<Fruit>();
}
public ICollectionView FruitsView { get; private set; }
#region ShowSelectedFruitOnly Property
private bool _showSelectedFruitOnly = true;
public bool ShowSelectedFruitOnly
{
get { return _showSelectedFruitOnly; }
set
{
if (value != _showSelectedFruitOnly)
{
_showSelectedFruitOnly = value;
FruitsView.Refresh();
OnPropertyChanged("ShowSelectedFruitOnly");
}
}
}
#endregion ShowSelectedFruitOnly Property
#region Add Methods
public void AddNewFruit()
{
Fruits.Add(new Fruit(NewFruitName, NewFruitColor));
NewFruitName = "";
NewFruitColor = "";
}
public void AddNewFruit(string name, string color)
{
Fruits.Add(new Fruit(name, color));
}
public void AddNewFruit(string name, Color color)
{
Fruits.Add(new Fruit(name, color));
}
#endregion Add Methods
#region NewFruitName Property
private String _newFruitName = default(String);
public String NewFruitName
{
get { return _newFruitName; }
set
{
if (value != _newFruitName)
{
_newFruitName = value;
OnPropertyChanged("NewFruitName");
}
}
}
#endregion NewFruitName Property
#region NewFruitColor Property
private String _newFruitColor = default(String);
public String NewFruitColor
{
get { return _newFruitColor; }
set
{
if (value != _newFruitColor)
{
_newFruitColor = value;
OnPropertyChanged("NewFruitColor");
}
}
}
#endregion NewFruitColor Property
#region Fruits Property
private static ObservableCollection<Fruit> _fruits;
public ObservableCollection<Fruit> Fruits
{
get { return _fruits; }
private set
{
if (value != _fruits)
{
_fruits = value;
FruitsView = CollectionViewSource.GetDefaultView(Fruits);
FruitsView.Filter = FruitFilterPredicate;
FruitsView.Refresh();
OnPropertyChanged("Fruits");
}
}
}
protected bool FruitFilterPredicate(Object o)
{
if (ShowSelectedFruitOnly)
{
return (o as Fruit).IsSelected;
}
return true;
}
#endregion Fruits Property
}
#endregion MainViewModel Class
}
App.xaml
<Application x:Class="Fruits.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Fruits"
StartupUri="MainWindow.xaml">
<Application.Resources>
<Style x:Key="ColorSwatch"
TargetType="ContentControl">
<Setter Property="Width"
Value="24" />
<Setter Property="Height"
Value="24" />
<Setter Property="IsTabStop"
Value="false" />
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<Rectangle HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Stroke="Gray"
StrokeThickness="1">
<Rectangle.Fill>
<SolidColorBrush Color="{Binding}" />
</Rectangle.Fill>
</Rectangle>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
<DataTemplate x:Key='FruitTemp'>
<StackPanel Orientation='Horizontal'
Margin='5'>
<TextBlock x:Name='tbName'
Text='{Binding FruitName}'
Margin='10,0,0,0'
Width='100' />
<TextBlock x:Name='tbColor'
Text='{Binding FruitColor}'
Margin='10,0,0,0'
Width='100' />
<ContentControl Width="16"
Height="16"
Style="{StaticResource ColorSwatch}"
Content="{Binding FruitColor}" />
<!-- The problem here was you were trying to bind Checked, an event,
instead if IsChecked, a bool? property.
-->
<CheckBox x:Name='cbSelected'
Content='Selected'
Margin='10,0,0,0'
IsChecked='{Binding IsSelected}' />
</StackPanel>
</DataTemplate>
</Application.Resources>
</Application>
The structure of my project
https://i.stack.imgur.com/l3p5z.png
My table in SQL Server:
CREATE TABLE [dbo].[Fruits]
(
[ID] [uniqueidentifier] NOT NULL,
[FruitName] [nvarchar](50) NULL,
[FruitColor] [nvarchar](50) NULL,
[IsSelected] [nvarchar](1) NULL,
CONSTRAINT [PK_Fruit]
PRIMARY KEY CLUSTERED ([ID] ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
Please advise why the message said there was no primary key while it does exist
This exception message doesn't mean it requires a primary key to be defined in your database, it means it requires a primary key to be defined in your class.
Although you've attempted to do so:
private Guid _id; [Key] public Guid ID { get { return _id; } }
This has no effect, as Entity Framework ignores read-only properties. It has to: when it retrieves a Fruits record from the database, it constructs a Fruit object, and then calls the property setters for each mapped property. That's never going to work for read-only properties.
You need Entity Framework to be able to set the value of ID. This means the property needs to have a setter.
I came here with similar error:
System.InvalidOperationException: 'The entity type 'MyType' requires a primary key to be defined.'
After reading answer by hvd, realized I had simply forgotten to make my key property 'public'. This..
namespace MyApp.Models.Schedule
{
public class MyType
{
[Key]
int Id { get; set; }
// ...
Should be this..
namespace MyApp.Models.Schedule
{
public class MyType
{
[Key]
public int Id { get; set; } // must be public!
// ...
I found a bit different cause of the error. It seems like SQLite wants to use correct primary key class property name. So...
Wrong PK name
public class Client
{
public int SomeFieldName { get; set; } // It is the ID
...
}
Correct PK name
public class Client
{
public int Id { get; set; } // It is the ID
...
}
public class Client
{
public int ClientId { get; set; } // It is the ID
...
}
It still posible to use wrong PK name but we have to use [Key] attribute like
public class Client
{
[Key]
public int SomeFieldName { get; set; } // It is the ID
...
}
This worked for me:
using System.ComponentModel.DataAnnotations;
[Key]
public int ID { get; set; }
Make sure you have the following condition:
Use [key] if your primary key name is not Id or ID. Use the public keyword. Primary key should have getter and setter.
Example:
public class MyEntity {
[key]
public Guid Id {get; set;}
}
If you get the error:
The entity type 'DeviceFlowCodes' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. For more information on keyless entity types, see https://go.microsoft.com/fwlink/?linkid=2141943.
You are probably using a solution with Individual User Accounts and have used protected override void OnModelCreating(ModelBuilder modelBuilder) in ApplicationDbContext.
The error comes from ApiAuthorizationDbContext that has a public DbSet<DeviceFlowCodes> DeviceFlowCodes { get; set; }.
Solve the error by calling base.OnModelCreating(modelBuilder); in protected override void OnModelCreating.
Source:
https://github.com/IdentityServer/IdentityServer4/issues/3169
Your Id property needs to have a setter. However the setter can be private. The [Key] attribute is not necessary if the property is named "Id" as it will find it through the naming convention where it looks for a key with the name "Id".
public Guid Id { get; } // Will not work
public Guid Id { get; set; } // Will work
public Guid Id { get; private set; } // Will also work
When I used the Scaffold-DbContext command, it didn't include the "[key]" annotation in the model files or the "entity.HasKey(..)" entry in the "modelBuilder.Entity" blocks. My solution was to add a line like this in every "modelBuilder.Entity" block in the *Context.cs file:
entity.HasKey(X => x.Id);
I'm not saying this is better, or even the right way. I'm just saying that it worked for me.
Yet another reason may be that your entity class has several properties named somhow /.*id/i - so ending with ID case insensitive AND elementary type AND there is no [Key] attribute.
EF will namely try to figure out the PK by itself by looking for elementary typed properties ending in ID.
See my case:
public class MyTest, IMustHaveTenant
{
public long Id { get; set; }
public int TenantId { get; set; }
[MaxLength(32)]
public virtual string Signum{ get; set; }
public virtual string ID { get; set; }
public virtual string ID_Other { get; set; }
}
don't ask - lecacy code. The Id was even inherited, so I could not use [Key] (just simplifying the code here)
But here EF is totally confused.
What helped was using modelbuilder this in DBContext class.
modelBuilder.Entity<MyTest>(f =>
{
f.HasKey(e => e.Id);
f.HasIndex(e => new { e.TenantId });
f.HasIndex(e => new { e.TenantId, e.ID_Other });
});
the index on PK is implicit.
I happened to have tried everything:
made sure the property has a setter
tried using the [Key] annotation
used a property named "Id" with and without the [Key] annotation.
None of these worked, for a simple reason: my database was unavailable.
Fixing the connection to the database solved the "requires a primary key" issue.
(Weird that it's this error that shows even in that case.)
The entity type 'DisplayFormatAttribute' requires a primary key to be defined.
In my case I figured out the problem was that I used properties like this:
public string LastName { get; set; } //OK
public string Address { get; set; } //OK
public string State { get; set; } //OK
public int? Zip { get; set; } //OK
public EmailAddressAttribute Email { get; set; } // NOT OK
public PhoneAttribute PhoneNumber { get; set; } // NOT OK
Not sure if there is a better way to solve it but I changed the Email and PhoneNumber attribute to a string. Problem solved.
None of the answers worked until I removed the HasNoKey() method from the entity. Dont forget to remove this from your data context or the [Key] attribute will not fix anything.
Removed and added back in the table using Scaffold-DbContext and the error went away
In the DBContext I had this <List> code causing the error:
public DbSet<List<<Item>> Items { get; set; } = null!;
You can get around it by making another class, I made a class ListItem that has a List<Item> in it and then declare both:
public DbSet<Item> Items { get; set; } = null!;
public DbSet<ListItem> ListItems { get; set; } = null!;
If you're using FluentApi make sure you're applying your configuration class like this:
internal class MyModelConfiguration : IEntityTypeConfiguration<MyModel>
{
public void Configure(EntityTypeBuilder<MyModel> builder)
{
builder.ToView("MyView", "dbo");
...
protected void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.ApplyConfiguration(new MyConfiguration());
...
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DbSet<Fruit>.Localshould be anObservableCollection<Fruit>you can bind to. It tracks all entities loaded into the context. Then (or before), just ensure you load the entities into the context (context.Fruits.Load();) and it should work. This requires you to keep the context around at least as long as your view model. Opinions vary on whether contexts should be short-lived or long-lived. Personally, in this case, I'd opt for a long-lived context.ObservableCollection<Fruit>, don't you? You're doing it in the code you've shown in your question. So all you'd need to do instead of creating a brand newObservableCollection<Fruit>object is using the one EF creates for you.