As you already stated - most of your try-catch blocks have no any exception handling, so the only thing they do is hiding any error (exception) you have in your code...
Do not use try-catch without good reason!!! Never!!! Try-catch is very expensive and for that it intended for
exceptional errors only...Do not use it as a solution for input validation for instance or to overcome problems of missing files and so on...
If you want to handle all unhandledexceptions in one place utilize the Application_Error method in Global.asax...
https://msdn.microsoft.com/en-us/library/24395wz3(v=vs.140).aspx[
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