Map System.Uri using Entity Framework Fluent Api

Question

Pretty simple question. I have a model that has a property which is a System.Uri type. Uris don't have a default parameterless constructor, and no ID field. Is there any way to override my model generation to store it in the DB in a custom way (e.g. just as a string)? In NHibernate, I've done this before by implementing IUserType, but I could not find yet a similar mechanism in CodeFirst.

Obviously, I could create a custom type that uses a Uri under the hood and exposes regular mappable properties & constructor, I'm just curious if there's any way to map this system type so that I don't have to make a wrapper like that.

score 34 · Answer 1 · answered Jun 11 '18 at 13:47

This is a very old question but I just had the same question today. With Entity Framework Core 2.1, you can set up a Value Conversion:

public class MyEntityDbConfiguration : IEntityTypeConfiguration<MyEntity>
{
    public void Configure(EntityTypeBuilder<MyEntity> builder)
    {
        builder.Property(e => e.UriField)
                .HasConversion(v => v.ToString(), v => new Uri(v));
    }
}

public class MyDbContext : DbContext
{
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.ApplyConfiguration(new MyEntityDbConfiguration());
    }
}

score 9 · Accepted Answer · edited Jan 20 '15 at 03:39

9

EF does not support custom type mappings like NH.

For System.Uri in particular, I'd use a wrapper property and map the actual value as a string; it's not that bad.

edited Jan 20 '15 at 03:39

Shimmy Weitzhandler

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answered Feb 18 '11 at 12:57

Diego Mijelshon

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Yeah, what I ended up doing was just using a String and then doing a DataType validation attribute. – Paul Feb 18 '11 at 15:59
I think they got support in 6, not 5. – Diego Mijelshon Nov 30 '13 at 20:29
4

Can you provide an example or a code snippet for clarification? – A-Sharabiani Jul 21 '15 at 20:01

score 6 · Answer 3 · answered Jan 20 '15 at 04:07

Unfortunately, there is no direct way to map System.Uri to string with EF.

You could however use Data Annotations and attribute your URL property as follows:

[DataType(DataType.Url)]
public string Link { get; set; }

This will able to tell some services that this should be displayed and validated as a URL (ASP.NET and Silverlight for instance have built in support for it).

score -1 · Answer 4 · answered Feb 18 '11 at 14:18

-1

Try doing this..

[Column(Name="MyUri", TypeName="string")]
public Uri MyUri

Make sure you add reference needed for Column Attribute

using System.ComponentModel.DataAnnotations;

Hope that helps...

answered Feb 18 '11 at 14:18

Vamsi Krishna Rallabhandi

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Just wanted to make sure I am referring to CTP5 of EF Code First – Vamsi Krishna Rallabhandi Feb 18 '11 at 15:11
6

No joy, this did not work. I still get the "Entity would not round-trip" error. – Paul Feb 18 '11 at 15:59

Map System.Uri using Entity Framework Fluent Api

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