Pass user selected parameter

I have a report where the user will clik on a field value and anotherreport will run and appear. I want to pass the field value the userclicks on as a parameter to the report so when the second report appersit will have been filtered by the user selected value.

Pass the parameter in the URL to the report you are opening, and on the PageLoad method of the aspx page that contains the target report, just create a new ReportParameter using the value of the query string, add it to an array, and call report.SetParameters() with that array.