How to create an editable previewable report?

Question

The Situation (the report is  CrystalReports.Engine.ReportDocument):
I load the report (.Load(Template)) and  set data (.SetDataSource(DataTable)). I save the report (.SaveAs or .Export). The Template does not necessary contains fields in DataTable used as datasource.
When I open the created report in "Crystal Reports 2011" the report preview is shown.  When I switch to the design tab I can drag fields to the report, but when I switch to the preview again a dialog asking for ado.net xml datafile is shown and when canceled (I have no datafile) empty preview is shown. In Visual Studio 2010 (CRVS 2010?) I see the preview when I cancel the dialog and click the design and  the preview again.
The Question:
Is it possible to create a report containing data with the preview working after report is edited?
Note:
I can achieve the desired behavior with external data file, but this soulution is not very convenient.

Answer 1

Ah... that helps a lot...
A couple of ways to go about this. From your template report compare the fields that exist in the report with those your Query has and add them into the Report. You can use the Command Object to append the fields and then the report will need to be refreshed against the XML file. In this case though the report will need to be ran again.
Another option is to export your data from your Query into a DataSet and simply .setlocation to the DS, great for small amounts of data, less than 2K rows or so but you'll have to test for the limits.
Another option is to to use RAS to completely create the report from nothing. See these samples on how to:
http://wiki.sdn.sap.com/wiki/display/BOBJ/CrystalReportsSDKSampleApplications
Bottom line is if you change the fields in a report it is going to have to be refreshed so the report can add/update the field reference list saved in the RPT file. If they don't match CR will simply delete all fields it can't match up.
If using RAS to Create the report and set it to the new field list then you can build your own "Report Designer"
As for running the Query again, that depends on how and where the data exists. If you save your date results into an XML file then it won't hit the DB again.
This will generate the XML file:
            ds.WriteXml(@"D:\Atest\list_of_workflows.xml");
            ds.WriteXmlSchema(@"D:\Atest\list_of_workflows.xsd");
Then load the XML file into a Dataset and then simply use:
rpt.SetDataSource(ds);
To set the Report to the XML file.
XML is the preferred way and it doesn't have any memory limitations as Active DataSets do. ( MS limitation due to security, CR can't access the original so we have to make a copy which effectively doubles the amount of memory required )
Don