Question

I’m using EF 4.1 Code First, with a Fluent Mapping:

Entity:

public class MyClass
{
    public int MyClassID { get; set; }
    public string Name { get; set; }
}

Mapping:

public class MyClassMapping: EntityTypeConfiguration<MyClass>
{
    public MyClassMapping()
    {
        Map(t => t.ToTable("MyClass"))
             .HasKey(t => t.MyClassID);

        Property(t => t.MyClassID)
             .IsRequired()
             .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        Property(t => t.Name)
             .IsRequired()
             .HasMaxLength(200);
    }
}

Given this configuration (and a number of similar declarations/mappings for other entities), if I know the type of the entity class (ie MyClass) is it possible to get the Type and Name of the key property of the entity class? – Since I’ve defined it in the mapping, shouldn’t I be able to get this back from either IDbSet for MyClass or my DbContext derived Entity container?

I’m not interested in just assuming that keyname = classname + "ID" or similar – how is it done properly from the mappings?

Answer 1

You need to access the MetadataWorkspace

public class MyContext : DbContext
{

    public void Test()
    {            
        var objectContext = ((IObjectContextAdapter)this).ObjectContext;

        var mdw = objectContext.MetadataWorkspace;

        var items = mdw.GetItems<EntityType>(DataSpace.CSpace);
        foreach (var i in items)
        {
            Console.WriteLine("Class Name: {0}", i.Name);
            Console.WriteLine("Key Property Names:");
            foreach (var key in i.KeyMembers)
            {
                Console.WriteLine(key.Name);
            }
        }
 }