Generic value converter for strongly typed ids in ef core 8

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04-10-2024

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Simplifying Your EF Core 8 Development: A Generic Value Converter for Strongly Typed IDs

Problem: Working with strongly typed IDs in EF Core 8 often requires creating a separate value converter for each entity. This can lead to repetitive code and make your project less maintainable.

Solution: A generic value converter simplifies this process by providing a reusable solution for converting strongly typed IDs to and from their underlying database representation.

Scenario:

Imagine you have various entities in your EF Core 8 application, each using a unique strongly typed ID.

public class Product
{
    public ProductId Id { get; set; }
    // ... other properties
}

public class Order
{
    public OrderId Id { get; set; }
    // ... other properties
}

// ... other entities with unique ID types

Instead of writing a separate value converter for each ID type, you can use a generic converter:

public class StronglyTypedIdValueConverter<TId, TValue> : ValueConverter<TId, TValue>
    where TId : struct 
    where TValue : struct
{
    public StronglyTypedIdValueConverter(Func<TId, TValue> convertToProvider,
                                           Func<TValue, TId> convertFromProvider) 
        : base(convertToProvider, convertFromProvider)
    {
    }
}

How it Works:

1. Generic Parameters: The StronglyTypedIdValueConverter takes two generic parameters: TId represents the strongly typed ID type (e.g., ProductId), and TValue represents the underlying database value type (e.g., Guid).

2. Constructor: The constructor accepts two functions (convertToProvider and convertFromProvider) to handle the conversion logic between the two types.

3. Usage: You can use this converter with your model builder in EF Core 8:

   modelBuilder.Entity<Product>()
       .Property(p => p.Id)
       .HasConversion(new StronglyTypedIdValueConverter<ProductId, Guid>(
           productId => productId.Value,
           guid => new ProductId(guid)
       ));
   
   modelBuilder.Entity<Order>()
       .Property(o => o.Id)
       .HasConversion(new StronglyTypedIdValueConverter<OrderId, Guid>(
           orderId => orderId.Value,
           guid => new OrderId(guid)
       ));
   

Benefits of Using a Generic Value Converter:

• Reduced Code Duplication: No more writing individual converters for each ID type.
• Improved Maintainability: Changes to the conversion logic only need to be made in one place.
• Consistency: Ensures consistent handling of strongly typed IDs across your application.

Additional Notes:

• Customization: You can easily customize the StronglyTypedIdValueConverter by overriding the ConvertToProvider and ConvertFromProvider methods.
• Database Considerations: The underlying database type (TValue) should be chosen based on your database schema.

Conclusion:

A generic value converter for strongly typed IDs in EF Core 8 can significantly improve the maintainability and consistency of your code. This approach allows you to manage your entities with unique IDs more efficiently while keeping your database interactions streamlined.