Morse code translator in C#
Is translator really a translator? IMO a better name could be dictionary.

I also don't understand an idea to create variables like dot and dash.
{'a', ".-"} would be much clearer.

Don't use misleading function names. The function getUserInput does much more than getting something from user! It also translates the text and prints it. So, in Main, I'd write:

input = getUserInput();
morse = translate(input);
PrintOnScreen(morse);


Be consistent in naming: now some functions have names starting with capital letter, some not.