title: FastMember and nullable properties
body: <p>i'm having an issue using fastmember, where by i have a public nullable property (datetime) for my class, but when i try and insert it into the db the column value is an empty string an not a null, which causes an exception to be thrown, any ideas on how to make the column value null?</p>
  
  <pre><code>public class MyClass
  {
      public DateTime? MyDate {get;set;}
  }
  
  DataTable testTable = new DataTable();
  using (var reader = ObjectReader.Create(myClassList))
  {
      testTable.Load(reader);
  }
  
   using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["connection"].ConnectionString))
   {
       SqlTransaction transaction = null;
       connection.Open();
       try
       {
           transaction = connection.BeginTransaction();
           using (var sqlBulkCopy = new SqlBulkCopy(connection, SqlBulkCopyOptions.TableLock, transaction))
           {
                sqlBulkCopy.BulkCopyTimeout = 0;
                sqlBulkCopy.BatchSize = batchSize;
                sqlBulkCopy.DestinationTableName = "myTable";
                for (var cols = 0; cols &lt; testTable.Columns.Count; cols++)
                {
                     sqlBulkCopy.ColumnMappings.Add(cols, cols);
                }
  
                sqlBulkCopy.WriteToServer(testTable);
            }
            transaction.Commit();
        }
        catch (Exception ex)
        {
            transaction.Rollback();
            throw ex;
        }
    }
  </code></pre>
  
  <p>if releasedate is null then it will always put it into the table as a blank string rather than a null, is there a way to force it to be null? or to interpret the empty string as a null in the sql bulk copy?</p>