Deleting multiple files with wildcard

You can use the Directory.GetFiles method with the wildcard overload. This will return all the filenames that match your pattern. You can then delete these files.

I know this has already been answered and with a good answer, but there is an alternative in .NET 4.0 and higher. Use Directory.EnumerateFiles(), thus:

foreach (string f in Directory.EnumerateFiles(myDirectory,"f*.txt"))
{
    File.Delete(f);
}

The disadvantage of DirectoryInfo.GetFiles() is that it returns a list of files - which 99.9% of the time is great. The disadvantage is if the folder contains tens of thousands of files (which is rare) then it becomes very slow and enumerating through the matching files is much faster.

You can use the DirectoryInfo.EnumerateFiles function:

var dir = new DirectoryInfo(directoryPath);

foreach (var file in dir.EnumerateFiles("f*.txt")) {
    file.Delete();
}

(Of course, you'll probably want to add error handling.)