How do I create directory if it doesn't exist to create a file?

Question

To Create

(new FileInfo(filePath)).Directory.Create() before writing to the file.

....Or, if it exists, then create (else do nothing)

System.IO.FileInfo file = new System.IO.FileInfo(filePath);
file.Directory.Create(); // If the directory already exists, this method does nothing.
System.IO.File.WriteAllText(file.FullName, content);

You can use following code

  DirectoryInfo di = Directory.CreateDirectory(path);

As @hitec said, you have to be sure that you have the right permissions, if you do, you can use this line to ensure the existence of the directory:

Directory.CreateDirectory(Path.GetDirectoryName(filePath))

An elegant way to move your file to an nonexistent directory is to create the following extension to native FileInfo class:

public static class FileInfoExtension
{
    //second parameter is need to avoid collision with native MoveTo
    public static void MoveTo(this FileInfo file, string destination, bool autoCreateDirectory) { 

        if (autoCreateDirectory)
        {
            var destinationDirectory = new DirectoryInfo(Path.GetDirectoryName(destination));

            if (!destinationDirectory.Exists)
                destinationDirectory.Create();
        }

        file.MoveTo(destination);
    }
}

Then use brand new MoveTo extension:

 using <namespace of FileInfoExtension>;
 ...
 new FileInfo("some path")
     .MoveTo("target path",true);

Check Methods extension documentation.