Show Name Property on a foreignkey relationship - foreign-keys

Question

I have a selectList of foreignkey (like a parent). Currently, the ID are binded for the value and item name. I want to change that for my Name property:
Here's my models:
public class Genus
{
public int GenusID { get; set; }
public EnumCategory Category { get; set; }
public string Name { get; set; }
public List<Species> Species { get; set; }
}
public class Species
{
public int SpeciesID { get; set; }
public int GenusID { get; set; }
public virtual Genus Genus { get; set; }
public string Name { get; set; }
}
On my Create and Edit Species page I have this code:
<select asp-for="Species.GenusID" class ="form-control" asp-items="ViewBag.GenusID"></select>
This code are generated by default when We Add Razor Page Scaffold. Well, the result are on the line 1, and what I want of result on the line 2:
<option selected="selected" value="1">1</option>
<option selected="selected" value="1">NameProperty</option> <!-- Species.Genus.Name -->
Do you have an idea to make that right ?
Thanks per advance

Answer 1

Looking at the code for the NavigationMetadata class in the scaffolding repo (https://github.com/aspnet/Scaffolding) I have found the following commented code which describe the behaviour.
// The default for the display property is the primary key of the navigation.
DisplayPropertyName = PrimaryKeyNames[0];
// If there is a non nullable string property in the navigation's target type, we use that instead.
var displayPropertyCandidate = navigation
.GetTargetType()
.GetProperties()
.FirstOrDefault(p => !p.IsNullable && p.ClrType == typeof(string));
if (displayPropertyCandidate != null)
{
DisplayPropertyName = displayPropertyCandidate.Name;
}
So if you want the Name property to show by default instead of the ID, then ensure it is the first string property in the model (yours already is), and then make sure it's not nullable.
protected override void OnModelCreating(ModelBuilder builder)
{
// ...
builder.Entity<Genus>().Property(l => l.Name).IsRequired();
// ...
}