How to check if I can create a file in a specific folder

Question

I need to know if I can create a file in a specific folder, but there are too many things to check such as permissions, duplicate files, etc. I'm looking for something like File.CanCreate(@"C:\myfolder\myfile.aaa"), but haven't found such a method. The only thing I thought is to try to create a dummy file and check for exceptions but this is an ungly solution that also affects performance. Do you know a better solution?

Answer 1

In reality, creating a dummy file isn't going to have a huge performance impact in most applications. Of course, if you have advanced permissions with create but not destroy it might get a bit hairy...

Guids are always handy for random names (to avoid conflicts) - something like:

string file = Path.Combine(dir, Guid.NewGuid().ToString() + ".tmp");
// perhaps check File.Exists(file), but it would be a long-shot...
bool canCreate;
try
{
    using (File.Create(file)) { }
    File.Delete(file);
    canCreate = true;
}
catch
{
    canCreate = false;
}