That said, by all means if you know SOLID well you can apply the principles in what you're doing, the ways you avoid breaking them just may be different.
Now then, as for Frameworks, personally as another C# dev I have found JQuery to be hands down the best to work with and feels most similar to working with the .NET framework to me in that it gives you tools but doesn't force your model in any way.
I would personally say if like me you're a back-end guy which I'm guessing to be the case considering you're now asking about what front-end framework to work with: Stay away from the large frameworks that try to force an object model structure onto you. Stick with JQuery and other utilitarian ones like it, I can suggest Handlebars for templating. Other than those (and similar ones you'll find, oh yeah moment.js is a great utility) I would say avoid the overarching "you must use this pattern" frameworks, as it's uncomfortable to a C# developer used to making the pattern and system model that fits their problem rather than the one that fits their technology stack.