基于c# Windows应用程序中选择的组合框查看水晶报表

我使用了下面的代码，但是没有得到输出

SqlDataAdapter da = new SqlDataAdapter("select ddate,details from activitys where customerid=(Select customerid from crmtbe where companyname='" + comboBox1.Text + "')", con);
            DataSet dt = new DataSet();
            da.Fill(dt, "activitys");
            CrystalReport3 report = new CrystalReport3();
            report.SetDataSource(dt.Tables["activitys"]);
            crystalReportViewer1.ReportSource = report;
            crystalReportViewer1.Refresh();