A customer is moving from Impromptu to SSRS. One of the SSRS missing features that was very important for this customer was the Imprompu pick list that allows users to copy a list of parameter values, such as a list entered in Notepad, to the parameter prompt. For example, the user might get a list of account codes via e-mail and this list may vary from day to day. Instead of hardcoding the list in the query WHERE clause or in the parameter default values, the user wants an easy way to copy and paste the parameter values.
Actually, SSRS supports this scenario just fine and without any custom coding on your part. You just need to add a multivalued parameter of type Text and code your SQL query to use an IN clause as usual. The attached report shows how this is done. Just copy the codes below and paste in the parameter to test the report.