ssrs report error ""String reference not set to an instance of a String"-- error coming randonly on calling report first time of the day. reports called from dotnet application.

Question

ssrs report error ""String reference not set to an instance of a String"-- error coming randonly on calling report first time of the day. reports called from dotnet application.

---

Moved from: Community Center | Discuss the Q&A site | Site suggestion

Answer 1

The error message "String reference not set to an instance of a String" typically indicates that there is an attempt to use a string variable that has not been initialized or is set to null. This can occur in SSRS reports if there are expressions or parameters that are not properly set or if there are issues with the data being returned from the database.

To troubleshoot this issue, consider the following steps:

1. Check Report Parameters: Ensure that all report parameters are being passed correctly and are not null. If a parameter is expected to have a value but is null, it can lead to this error.
2. Review Expressions: Look through the expressions used in the report for any that may reference string variables. Ensure that these variables are initialized properly before they are used.
3. Data Source Issues: Verify that the data source is returning the expected results. If the data source returns null or unexpected values, it may cause this error.
4. Error Handling: Implement error handling in your .NET application to catch and log any exceptions that occur when calling the report. This can help identify the exact point of failure.
5. Testing: Try running the report in SQL Server Data Tools (SSDT) to see if the error can be reproduced outside of the application context. This can help isolate whether the issue is with the report itself or with how it is being called from the application.

By following these steps, you should be able to identify and resolve the underlying cause of the error.

Answer 2

Perhaps you can post/ask in the SQL forum?

https://techcommunity.microsoft.com/category/sql-server/discussions/sql-server-reporting-services