StellarAdmin is still in development. We'd love for you to try it out and get your feedback, but please be advised that you may run into bugs. Changes to public APIs may also occur.

Defining fields for your resource

Specifying display fields

Display fields are fields that will be displayed to the user in the various views, such as the resource index view, resource detail view, and the edit and create views. You can specify the display fields of your resource by calling the AddField() method when registering your resource. The AddField method takes an expression parameter which specifies a lambda expression that must be evaluated to return the value of the field.

Let's assume you have the following Author class defined.

public class Author
    public string Bio { get; set; }

    public int Id { get; set; }

    public string Name { get; set; }

    public string Photo { get; set; }

When registering the resource for the Author class, you can define each of the display fields as follow:

builder.AddResource<Author>(rb =>
    rb.AddField(a => a.Photo);
    rb.AddField(a => a.Name);
    rb.AddField(a => a.Bio);

Note that in the code example above we did not declare a display field for the Id property. This is because the Id property is the key field and not something we necessarily want to display to the user in the user interface.

Specifying the name of the field

Each field requires a unique name which StellarAdmin will try and determine from the lambda expression passed to the AddField() method. This works when the lambda expression is a member expression, but if you create a complex expression, StellarAdmin will not be able to determine the name of the field.

The following code represents a complex expression where StellarAdmin will not be able to determine the name of the field:

rb.AddField(a => $"{a.FirstName} {a.LastName}");

In this case, you will need to specify the optional configure parameter for the AddField method. You will be passed an instance of FieldDefinitionBuilder<TResource> that allows you to further configure the field. To specify the name of the field, you can call the HasName() method.

rb.AddField(a => $"{a.FirstName} {a.LastName}", f => f.HasName("Fullname"));

Specifying display attributes

The configure callback parameter of the AddField method also allows you to control various display properties of the field. You can, for example, specify the label and help text for a field by calling the HasLabel() and HasHelpText() methods.

rb.AddField(a => a.Bio,
    f =>
        f.HasHelpText("Enter a short biography of the author");

Specifying a key field

It is essential to specify a key field for a resource so StellarAdmin knows how to retrieve specific instances of a resource. StellarAdmin can automatically determine the key field of a resource under the following conditions:

  • The property that represents the primary key of your class has a [Key] attribute specified
  • When using the DbContextDataSource, StellarAdmin will request the primary key details from Entity Framework. This means that as long as Entity Framework can determine the primary key of your entity - whether that be by convention, Data Annotations or the Fluent API - StellarAdmin will be able to determine it as well.

In cases where the key field cannot be automatically determined, you can specify it manually when you register your resource as follows:

builder.AddResource<Author>(rb =>
    rb.HasKey(a => a.Id);
    // ...