Question

I have uploaded a report and created a datasource in Reporting Services 2005. When I view the report through Report Manager, it runs successfully and displays correctly.

However, when I try to open this report in an ASP.net application which uses a ReportViewer control to view the report, it returns an exception:

Exception Details: Microsoft.Reporting.WebForms.ReportServerException: The data source
‘ReportTesting’ cannot be found. (rsDataSourceNotFound)

A warning is logged in Event Viewer on the ReportServer server:

**Process information: 
    Process ID: 3536 
    Process name: w3wp.exe 
    Account name: NT AUTHORITY\NETWORK SERVICE** 

**Exception information: 
    Exception type: ReportServerException 
    Exception message: The data source 'ReportTesting' cannot be found. (rsDataSourceNotFound)** 

I can’t figure out why the report and datasource runs fine through ReportManager but won’t when I run it via the RepotrViewer. There are other reports on the server (using different datasources) which are running fine.

Update:
To confuse matters further – If I go untick ‘Enable this data source’ in ReportManager, the following is returned when I try to run the report in the ReportViewer control:

Exception Details: Microsoft.Reporting.WebForms.ReportServerException:
The report server cannot process the report. A data source associated
with the report has been disabled. (rsDataSourceDisabled)

If I retick the option to ‘Enable this data source’, it reverts to the original exception.

Answer 1

I finally discovered the cause / resolution!

I opened the .rdl file in a text editor and noticed that the Datasets were still pointing to the previous datasource.

<Query>
    <DataSourceName>[old datasource name]</DataSourceName>

I replaced all references to the previous datasource with the new datasource and it now runs successfully.