I am currently making an ASP.Net and C# page, which is a front end for some reports.
I also want to run some queries, from the same data source as the reports (each report uses just 1 data source).
Is it possible to extract the data source connection information from a report, using either ReportingService2005 or ReportExecutionService members, so that it can be reused in an SqlConnection?
You can use the ReportingService2005 API to get the datasource used by a particular report.
You need the full path of the report (which I assume you have), and then use it to query the reporting service for its data source (API).
The ds in the code above is either a DataSourceDefinition or a DataSourceReference. If it's a definition you can just cast it into that type and then get the connection string using the following code.
If it's a datasourcereference you need to check out the API.
Hopefully this is of some help. It will list all the properties, but specifically it pulls out the connection string: