“dataset不支持system.nullable”

Question

我在WPF中创建Crystal Report并且异常生成“数据集不支持system.nullable”

private void btngenrateReport_Click(object sender, RoutedEventArgs e)
{
    ReportDocument report = new ReportDocument();
    report.Load("../../CrystalReport1.rpt");
    var q = (from c in db.TableClients
             select new { c.ClientID, c.Name, c.City, c.Phone, c.Email }).ToArray();

    report.SetDataSource(q);

    crystalReportsViewer1.ViewerCore.ReportSource = report;
}