ASP.NET C＃根据下拉列表更改连接字符串

I'm still very new to ASP.Net C#, I have this piece of code which works fine. I have multiple connection strings in the web.config file and I switch between them based on the text of my drop down list. I was hoping for some advice of any neater/cleaner method to archive this rather than what I have below (if there is). Thanks!I'm still very new to ASP.Net C#, I have this p