Field in Crystal report

For the report design, u set the field from DB. and then during form load, set ur datasource value to the report dynamically. Then it will take the value from ur datasource only, not from DB table.
 
//Begin: Bind the reports dynamically
            DataTable dtReports = BindReports();
            rpt.SetDataSource(dtReports);
            //End: Bind the reports dynamically

            //Begin: Update the report label value from All to the entered employee name in the text box
            TextObject myTextObjectOnReport;
            if (rpt.ReportDefinition.ReportObjects["txtEmpName"] != null)
            {
                myTextObjectOnReport = (TextObject)rpt.ReportDefinition.ReportObjects["txtEmpName"];
                myTextObjectOnReport.Text = txtName.Text;
            }

            crystalReportViewer1.ReportSource = rpt;
            crystalReportViewer1.Refresh();
            //End

How can i do if i do not use your steps from 1 to 9 and if my data comes from multitable what should i do . I do not want to give the report the database at designer .

Try the below steps
1. Right click from report
2. Database --> DatabaseExpert
3. Expand "Create New Connection"
4. Expand OLEDB (ADO)
5. Select "Microsoft OLEDB provider for SQL Server" then click "Next"
6. Give the database credentials and click Next and then Finish(Click check box Integrated Security for windows authentication)
7. Select the table from Database Expert window then click OK
8. Expand Database fields from Field Explorer
9. Drag and drop the Table field inside the Details section.
10. To change the font style right click from the field and click format object and change ur font style in Font Tab and click OK
 
Dynamically set the Datasource into report viewer:
 
http://www.c-sharpcorner.com/UploadFile/MuthuA/1640/?ArticleID=b7d43f06-4403-407e-bdf1-1b9a78307082