How Can I Find The Path To A Folder from a Controller Constructor in ASP.NET MVC?

Question

I am trying to get the path to a folder in my website root and save it to a class property when my controller constructor is called:

public TestController:Controller{
    string temp;

    public TestController(){
        temp = "";
        }

    }

I have tried the following:

temp = Server.MapPath("~/TheFolder/"); // Server is null - error.
temp = Request.PhysicalApplicationPath + @"TheFolder\"; // Request is null - error.

Any ideas?

Answer 1

AppDomain.CurrentDomain.BaseDirectory will give you the root of your site. So:

temp = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TheFolder");

(Update thanks to Marc Gravell's comment)

Answer 2

Try going through the ControllerContext. Forgive my syntax, but it should something like this:

base.[Controller?]Context.HttpContext.Server.MapPath();

If Server is still null in that situation, are you running outside of a web request (ie. in a test)?

Answer 3

Do you actually need this path during the constructor? If you don't need it until the main page cycle begins, consider deferring it - just using a regular property; something like

public string BasePath {
    get { return Server.MapPath("~/TheFolder/"); }
}

Then when this is used during the page cycle, it should be fine. You could cache it if you really want to, but I don't imagine this is going to be a bottleneck:

private string basePath;
public string BasePath {
    get {
        if(basePath == null) basePath = Server.MapPath("~/TheFolder/");
        return basePath;
    }
}