How to map C# enum to PostgreSQL enum using Dapper.FastCRUD?

I have a class Sample, one of whose properties is an enum, TargetType. I have a corresponding table samples defined in a PostgreSQL database, along with a matching enum type, targettypes.

With Dapper.FastCRUD, I can retrieve records from the table successfully. However, I get an error during insertion:

Npgsql.PostgresException (0x80004005): 42804: column "target_type" is of type targettype but expression is of type integer

EDIT 1: MoonStorm - creator of Dapper.FastCRUD - clarified that DB-CLR type conversions are handled by Dapper. So, now the question is:

How do I tell Dapper to map the C# enum TargetType to PostgreSQL ENUM TYPE targettype?

The enum is defined as:

public enum TargetType
{
    [NpgsqlTypes.PgName("Unknown")]
    UNKNOWN = 0,

    [NpgsqlTypes.PgName("Animal")]
    ANIMAL = 1,

    [NpgsqlTypes.PgName("Car")]
    CAR = 2,

    [NpgsqlTypes.PgName("Truck")]
    TRUCK = 3
}

And the class is defined as:

[Table("samples")]
public partial class Sample
{
    [Column("recording_time")]
    public DateTime RecordingTime { get; set; }

    [Column("x_position")]
    public double X_Position { get; set; }

    [Column("x_velocity")]
    public double X_Velocity { get; set; }

    [Column("y_position")]
    public double Y_Position { get; set; }

    [Column("y_velocity")]
    public double Y_Velocity { get; set; }

    [Key]
    [Column("id")]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public ulong Id { get; set; }

    [Column("target_type")] // <--- This is the offending column
    public TargetType TargetType { get; set; }

}

EDIT 2: Revised the example with working insert.

Illustration of usage:

using Npgsql;
using Dapper.FastCrud;
...

NpgsqlConnection.MapEnumGlobally<TargetType>("public.targettype"); // ... (1)

OrmConfiguration.DefaultDialect = SqlDialect.PostgreSql;

(using NpgsqlConnection conn = ...) // Connect to database
{
    var samples = conn.Find<Sample>();  // <--- This works correctly
    foreach (Sample s in samples)
        Console.WriteLine(s);

    ... // Generate new samples

    using (var writer = conn.BeginBinaryImport(sql))
    {
        foreach (Sample s in entities)
        {
            writer.StartRow();

            writer.Write(s.TargetType);  // <--- This insert works, due to (1)
            ...
        }
    }

    foreach (Sample sample in sampleList)
        conn.Insert<Sample>(sample);    // <--- This throws PostgresException
    ...
}

You probably have to convert TargetType to a integer.

Untested but something like:

Get 
{
    return (int)this.TargetType;
}