Intellisense

For reasons that I cannot understand, intellisense stops working frequently in VS for me. Now, I am not sure if how much it happens to me nowadays has to do with how quickly the VS designer breaks. My WPF project, which does no work with date times, anywhere, rarely will show a preview of my XAML, and if I get a meaningful error, it's 'cannot convert value to DateTime'. However, it's now starting to actually tell me that all the objects in my code behind do not exist, if they are defined in the XAML. So, I have to code blind, where usually I use prefixes like txt and lbl and then intellisense helps me find the control I want. Now, as I code, I am told that InitializeComponent does not exist, and my variables do not exist, either. Of course, when I do a build, it builds and runs fine.