How to set FiddlerCore response to Textbox in c#

Question

I am using FiddlerCore in c# to decode a response from a url containing "getflags" and inside this url response has a lot of data; which changes time from time. I am wanting FiddlerCore to decode the response of the url; then find specific data; and if found; then set that data to textbox1.text. However, when it's doing so; it's saying "cannot convert type int to string"; even though it's set as a string. How can I accomplish my goal of reading the data; if found; then set that data as the text for textbox 1? Here is my code below:

                    if (session.uriContains("getflags"))
                {
                var baseage = "120960";
                session.utilDecodeResponse();

                    try
                    {                        
                        textBox1.Text = session.utilFindInResponse(baseage, false);
                        
                        session.bBufferResponse = false;
                        session.PoisonClientPipe();
                        session.PoisonServerPipe();
                    }
                    finally
                    {
                    }
                }