SpecFlow Selenium run on local webpage with Chrome - selenium

Question

I'm learning how to use SpecFlow with Selenium in Visual Studio 2015. I finished creating a simple webpage that has checkbox on it. Now I want to use SpecFlow with Selenium to test the checkbox selection. Since the webpage is HTML file and locally on my computer also Selenium does not have ChromeDriver version correctly, so I have to download the ChromeDriver to locally and copy the exe file to C:\Temp\SpecFlowDemo\packages folder.
Below is the code and I think the problem is using "BinaryLocation". I've searched online, but most posts I have seen, they use "setBinary" method, but based on the ChromeDriver version I have, "setBinary" does not exist. So I find "BinaryLocation" is the closest that I can use. But when I run the test via Visual Studio, it says "OpenQA.Selenium.DriverServiceNotFoundException: the chromedriver.exe file does not exist in the current directly" I already copy chromedriver.exe into my C:\Temp\SpecFlowDemo\packages folder. So not sure what is the issue.
IWebDriver webDriver;
ChromeOptions optionChrome;
[Given(#"There are five selections avaiable")]
public void GivenThereAreFiveSelectionsAvaiable()
{
string driverExe = #"C:\Temp\SpecFlowDemo\packages";//my SpecFlow project named SpecFlowDemo created with Visual Studio 2015
//initialize driver
optionChrome = new ChromeOptions();
optionChrome.AddArgument("--allow-file-access-from-files");
optionChrome.BinaryLocation = driverExe;//setBinary() does not exist
webDriver = new ChromeDriver(optionChrome);
webDriver.Navigate().GoToUrl(#"C:\Projects\WebDemo\index.html");//my webpage project
}