I have a problem passing a struct with an enum field.
I have this c++ code:

typedef struct st_mysql_bind
{
 ....
 my_bool       *error;
 enum enum_field_types buffer_type;
 ....
}MYSQL_BIND;

enum enum_field_types { MYSQL_TYPE_DECIMAL, MYSQL_TYPE_TINY,
            MYSQL_TYPE_SHORT,  MYSQL_TYPE_LONG,
                       ......};
my_bool STDCALL mysql_stmt_bind_result(MYSQL_STMT * stmt, MYSQL_BIND *
bnd);

I declared the following in c#:

    [StructLayout(LayoutKind.Sequential)]
    public unsafe class MYSQL_BIND
    {
               .....
        public sbyte error;
        public enum_field_types  buffer_type;
               .....
       }

    public enum enum_field_types
    {
        MYSQL_TYPE_DECIMAL, MYSQL_TYPE_TINY,
               MYSQL_TYPE_SHORT,  MYSQL_TYPE_LONG,
                 .......
       }
        [ DllImport( "libmySQL.dll", EntryPoint="mysql_stmt_bind_result" )]
        unsafe public static extern sbyte mysql_stmt_bind_result(IntPtr stmt,
ref MYSQL_BIND[] result);

When It calls mysql_stmt_bind_result it execute something like this:
            bind = new MYSQL_BIND[4];
            bind[0] = new MYSQL_BIND();
            bind[0].buffer_type = enum_field_types.MYSQL_TYPE_LONG;
                       mysql_stmt_bind_result(stmt, ref bind);

The problem is that the buffer_type of MYSQL_BIND type is not a valid
type (it means a value from the enum values) when executing
mysql_stmt_bind_result (I get an error from mysql_stmt_bind_result
because of the invalid number of buffer_type).

Is it the correct way to pass enum fields in structs?.

Any help would be appreciated.