Question

How can I check whether a path to a file that doesn’t necessarily exists points to a location inside a particular directory? Say I have a method:

bool IsInside(string path, string folder)
{
    //...
}

Then, if I call it like:

IsInside("C:\\Users\\Dude\\Hi", "C:\\Users\\Dude\\Hi\\SubFolder\\SubSubFolder\\tile.txt")

should return true (note the sub folder), but if I call it like:

IsInside("C:\\Users\\Dude\\Hi", "C:\\Users\\Dude\\BadFolder\\SubFolder\\SubSubFolder\\tile.txt")

should return false. The only thing I can think of right now is using string’s StartsWith, but sounds kinda hacky to me. I haven’t found a native .NET method that would check this either.

Answer 1

You could try the string.IndexOf method. If you use the overload with the StringComparison enumeration it should give you the result you need.

From above link:

Reports the zero-based index of the first occurrence of one or more characters, or the first occurrence of a string, within this string. The method returns -1 if the character or string is not found in this instance.

bool IsInside(string folder, string path)
{
   if (path.IndexOf(folder,StringComparison.OrdinalIgnoreCase) != -1)
        return true;
    else
        return false;