Excluir arquivos dentro um diretório, sem excluir o diretório

public static void copyDir(string sourceDirName, string destDirName, bool copySubDirs)

{

// Get the subdirectories for the specified directory.

DirectoryInfo dir = new DirectoryInfo(sourceDirName);

if (!dir.Exists)
    {
        System.Console.WriteLine(dir);
        throw new DirectoryNotFoundException(
            "Source directory does not exist or could not be found: "
            + sourceDirName); 
    } 
    else
    {           
        System.Console.WriteLine(dir);            
    }
    DirectoryInfo[] dirs = dir.GetDirectories();
    // If the destination directory doesn't exist, create it.
    if (!Directory.Exists(destDirName))
    {
        Directory.CreateDirectory(destDirName);
    }
    // Get the files in the directory and copy them to the new location.
    FileInfo[] files = dir.GetFiles();
    foreach (FileInfo file in files)
    {
        string temppath = Path.Combine(destDirName, file.Name);
        file.CopyTo(temppath, true);
    }
        // If copying subdirectories, copy them and their contents to new location.
        if (copySubDirs)
        {
             foreach (DirectoryInfo subdir in dirs) 
             {
              string temppath = Path.Combine(destDirName, subdir.Name);
              copyDir(subdir.FullName, temppath, copySubDirs);
             }
        }
    }