Resolving Object Null Exception in ASP.NET WebMethods: How to Set Session After Successful Login

Struggling with setting sessions in your ASP.NET application after successful login? Learn how to resolve the Object Null Exception error with this comprehensive guide. --- This video is based on the question https://stackoverflow.com/q/63529899/ asked by the user 'Peter Sun' ( https://stackoverflow.com/u/2252502/ ) and on the answer https://stackoverflow.com/a/63530936/ provided by the user 'Jeethendra' ( https://stackoverflow.com/u/14141234/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Asp.net/JQuery: Set session after successful login Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- How to Set Session After Successful Login in ASP.NET with jQuery When developing web applications, one common functionality you'll likely encounter is user authentication. Specifically, setting a session after a successful login can sometimes present challenges, especially when using ASP.NET and jQuery. In this guide, we'll explore a common issue — the Object Null Exception — that occurs while trying to create a session, and provide a clear solution to resolve this problem. Understanding the Problem Imagine you’re building a login page that connects to a SQL database to authenticate users. Using jQuery, you send a request to a web method that validates the user credentials. If the validation is successful, you intend to create a session and set a user ID. However, you encounter an Object Null Exception at the line where you try to set the session variable. This can stop your authentication process in its tracks and result in an incomplete user experience. Example Code that Triggers the Issue [[See Video to Reveal this Text or Code Snippet]] As you can see, the error occurs on the line where the session variable is set, leading to complications in processing user authentication. The Solution Fortunately, there's a simple solution that will help you avoid this Object Null Exception. The key lies in enabling session state in your web method, which is done by modifying the method’s attributes. Step-by-Step Instructions Modify WebMethod Attributes: You need to add the EnableSession = true attribute to your WebMethod definition. This allows you to use session variables in the web method. [[See Video to Reveal this Text or Code Snippet]] Test the Implementation: After making the above change, try running your application again. Log in with valid credentials and check if the session is being created successfully. Handle Exceptions: It’s always good practice to handle exceptions properly. Ensure that any potential errors during database operations are logged and handled gracefully, to improve the robustness of your application. Conclusion By enabling session state in your ASP.NET WebMethod, you can effectively resolve the Object Null Exception issue, allowing you to successfully create sessions after user authentication. These steps will help create a smoother user experience and ensure that your login functionalities work as intended. If you have encountered similar issues in the past or have any other questions regarding user authentication, feel free to leave your comments below! We're here to help.