.Net Entity Framework Core Unique index with Foreign Key

Question

Problem: Hi guys. Im using EF core 2.1 and I need to have in the Table InstallationInformation the attributes LicenceKey and Importrun(FK) to a unique index(combination).

Added Info: If im right with the research that i have made. I cant use Annotation [index] in .net Core 2.1 cause it not supported. I tryed to upgrade but it needed VS 2019 which i dont have. And to use VS 2019 I need windows 10 which i also not using.

Methods that i have tryed. I tryed the Annotation thing. But unfortunately it was not working. I found out that i could try using Fluent API and found out that i could map the attribute.

modelBuilder.Entity<InstallationInformation>(entity =>
            {
                entity.HasIndex(i => new { i.LicenceKey, i.ImportRun }).IsUnique();
            });

But as i was debbuging it had this error "InvalidOperationException: 'ImportRun' cannot be used as a property on entity type 'InstallationInformation' because it is configured as a navigation."

Code structure:

public class ImportRun
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int ImportRunId { get; set; }

        public DateTime ExtractedDate { get; set; }

        public DateTime ProcessDate { get; set; }

        public ResultCondition ProcessResult { get; set; }        

        public string FailureDescription { get; set; }

        [Required]
        public virtual ICollection<InstallationInformation> InstallationInformation { get; set; }

    }

public class InstallationInformation
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int InstallationInformationID { get; set; }

        [MaxLength(256)]
        public string LicenceKey { get; set; }

        [MaxLength(256)]
        public string ProductVersion { get; set; }

        [MaxLength(256)]
        public string ProductName { get; set; }        

        [MaxLength(256)]
        public string CompanyName { get; set; }

        public DateTime Timestamp { get; set; }
        [Required]
        public ImportRun ImportRun { get; set; }
    }

protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);

            modelBuilder.Entity<ImportRun>()
                .HasMany(c => c.InstallationInformation)
                .WithOne(e => e.ImportRun)
                .IsRequired();

            modelBuilder.Entity<InstallationInformation>(entity =>
            {
                entity.HasIndex(i => new { i.LicenceKey, i.ImportRun }).IsUnique();
            });
        }

Answer 1

Change:

            modelBuilder.Entity<InstallationInformation>(entity =>
            {
                entity.HasIndex(i => new { i.LicenceKey, i.ImportRun }).IsUnique();
            });

To:

            modelBuilder.Entity<InstallationInformation>(entity =>
            {
                entity.HasIndex(i => new { i.LicenceKey, i.ImportRunId }).IsUnique();
            });