I have come across a few people with the same issue that seemed to have solved the problem with System.addProperty(\"webdriver.chrome.driver\", \".../chromedriver.exe\");<
Old question, new answer (for what it's worth): just install the Nuget package Selenium.WebDriver.ChromeDriver. Chromedriver.exe will be in the directory bin/debug on the next build.
On this github page jsakamoto/nupkg-selenium-webdriver-chromedriver/ that after running Install-Package Selenium.WebDriver -Version 3.5.2
the chromedriver(.exe) lies below this folder
" {solution folder} /packages/Selenium.WebDriver.ChromeDriver. {ver} /driver/ {platform}"