How do I convert a file path to a URL in ASP.NET

Question

Basically I have some code to check a specific directory to see if an image is there and if so I want to assign a URL to the image to an ImageControl.

if (System.IO.Directory.Exists(photosLocation))
{
    string[] files = System.IO.Directory.GetFiles(photosLocation, "*.jpg");
    if (files.Length > 0)
    {
        // TODO: return the url of the first file found;
    }
}

Answer 1

So far as I know there's no single function which does this (maybe you were looking for the inverse of MapPath?). I'd love to know if such a function exists. Until then, I would just take the filename(s) returned by GetFiles, remove the path, and prepend the URL root. This can be done generically.

Answer 2

As far as I know, there's no method to do what you want; at least not directly. I'd store the photosLocation as a path relative to the application; for example: "~/Images/". This way, you could use MapPath to get the physical location, and ResolveUrl to get the URL (with a bit of help from System.IO.Path):

string photosLocationPath = HttpContext.Current.Server.MapPath(photosLocation);
if (Directory.Exists(photosLocationPath))
{
    string[] files = Directory.GetFiles(photosLocationPath, "*.jpg");
    if (files.Length > 0)
    {
        string filenameRelative = photosLocation +  Path.GetFilename(files[0])   
        return Page.ResolveUrl(filenameRelative);
    }
}

Answer 3

The simple solution seems to be to have a temporary location within the website that you can access easily with URL and then you can move files to the physical location when you need to save them.

Answer 4

For get the left part of the URL:

?HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority)
"http://localhost:1714"

For get the application (web) name:

?HttpRuntime.AppDomainAppVirtualPath
"/"

With this, you are available to add your relative path after that obtaining the complete URL.