System.Data.DataRowView shows in winforms combobox instead of actual data

After I load my combobox, it displays System.Data.DataRowView instead of data. I am using the correct column names as returned from the stored procedure (TimeframeDesc and TimeframeCode).

I get the message 'Cannot bind to the new display member' when debugging.

        private bool loadTimeframeList(out string msg)
    {
        msg = "";
        string spName = "schemaExec.SelTimeframeCode";
        bool result = true;
        SqlCommand cmd = new SqlCommand(spName);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Connection = _sqlConn;

        try
        {
            SqlDataAdapter rdr = new SqlDataAdapter(cmd);
            cmd.ExecuteNonQuery();
            DataTable dt = new DataTable();
            rdr.Fill(dt);

            cbTimeframe.DisplayMember = "TimeframeDesc";
            cbTimeframe.ValueMember = "TimeframeCode";
            cbTimeframe.DataSource = dt;             
        }
        catch (Exception ex)
        {
            result = false;
            msg = "Could not load Timeframe Codes" + Environment.NewLine + ex.Message;
        }
        return result;
    }