InterfaceType

interface InterfaceType {
	property: Int!
	method(arg1: Int!): Int!
}

type FieldType implements InterfaceType {
	property: Int!
	method(arg1: Int!): Int!
	property2: String!
}

Generated

• Model interface with properties for simple fields of the interface
• Controller interface with method for getting the actual Type System type of the object implementing the interface
• Default implementation of the controller interface

Model

Model class is generated with properties generated according to same rules as for object types.

public partial interface IInterfaceType
{
    public string __Typename => "InterfaceType";
    public int Property
    {
        get;
    }
}

Controller

GraphQL execution requires to know the actual type of the interface during value completion. Controller interface is generated with IsTypeOf method to resolve the actual type.

public partial interface IInterfaceTypeController
{
    INamedType IsTypeOf(IInterfaceType instance, ISchema schema);
}

Default Controller implementation

Default implementation of the interface controller uses the generated __Typename property to fetch the named type from the schema.

public partial class InterfaceTypeController : IInterfaceTypeController
{
    public INamedType IsTypeOf(IInterfaceType instance, ISchema schema)
    {
        return schema.GetNamedType(instance.__Typename);
    }
}