CategoryModel has a property & dependency-property Color of type Object Brush (Complex data type) that can't be Stored using EF directly so I use Serialization and store it as string.
using System.ComponentModel.DataAnnotations.Schema;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
public class CategoryModel : UserControl{
...
[NotMapped] // Not mapped to the database
public Brush Color
{
get { return (Brush)GetValue(ColorProperty); }
set { SetValue(ColorProperty, value); }
}
public static readonly DependencyProperty ColorProperty =
DependencyProperty.Register("Color", typeof(Brush), typeof(CategoryModel), new PropertyMetadata(Brushes.Black));
...
}
so the solution is to use get & set to & from another property let's call it serializedBrush of type string.
the Problem is: the property is already using get & set to & from the dependency-property.
suggested this approach to ChatGPT: So I changed the dependency-property to serializedBrush string
public class CategoryModel : UserControl{
...
public Brush Color
{
get { return JsonSerializer.Deserialize<Brush>(SerializedBrush); }
set { SerializedBrush = JsonSerializer.Serialize(value); }
}
public static readonly DependencyProperty SerializedBrush=
DependencyProperty.Register("Color", typeof(string), typeof(CategoryModel));
}
AI comment: don't use dependency property to interact with the database, it is used more to deal with the business logic, and gave me the following solution
using System.ComponentModel.DataAnnotations.Schema;
using System.Windows;
using System.Windows.Media;
using System.Text.Json;
namespace YourNamespace
{
public class CategoryModel : DependencyObject
{
public static readonly DependencyProperty SerializedBrushProperty =
DependencyProperty.Register("SerializedBrush", typeof(string), typeof(CategoryModel));
[Column(TypeName = "nvarchar(max)")] // Specify column type for EF
public string SerializedBrush
{
get { return (string)GetValue(SerializedBrushProperty); }
set { SetValue(SerializedBrushProperty, value); }
}
public Brush Color
{
get { return JsonSerializer.Deserialize<Brush>(SerializedBrush); }
set { SerializedBrush = JsonSerializer.Serialize(value); }
}
}
}
but what about the dependency property of the Brush Color
adding another property to be used for serialization or change the color to RGB
for
a property that has < dependency-property > related to it, is the cause/source of the problem.
because you will then have 3 properties that you need to somehow identify the relation (getters & setters) between them.
Solution : we got 2 options:
First: use Value Conversion in the "OnModelCreating()" method in the DbContext.
you can do that in the model class (CategoryModel)
using System.ComponentModel.DataAnnotations.Schema;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
public class CategoryModel : UserControl{
...
[Column(TypeName = "nvarchar(24)")] // EF8 will automatically pick the pre-configured conversion method for it.
public Brush Color
{
get { return (Brush)GetValue(ColorProperty); }
set { SetValue(ColorProperty, value); }
}
public static readonly DependencyProperty ColorProperty =
DependencyProperty.Register("Color", typeof(Brush), typeof(CategoryModel), new PropertyMetadata(Brushes.Black));
...
}
Or in the DbContext OnModelCreating() method
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder
.Entity<CategoryModel>()
.Property(e => e.Color)
.HasConversion<string>();
}
Second: leverage Entity Framwork Core 8's ability to store complex types as JSON. (might provide the solution for it later)
Thank you everyone, and special thanks to Jeremy Lakeman.