Get all files from directory folder using asp.net c#

// Add namespace

using System.IO;

// listed files

       // 1. for all files of directory folder

       public void getfiles()

    {

        string targetDirectory = Server.MapPath("slider/images");

        DirectoryInfo d = new DirectoryInfo(targetDirectory);//get directory folder

        FileInfo[] Files = d.GetFiles("*"); //get all files from Folder

        string str = "";

        foreach (FileInfo file in Files)

        {

            str = str + "" + file.Name + ", ";

        }

    } 

 // 2. for selected extension files only of directory folder

    public void getfiles()

    {

        string targetDirectory = Server.MapPath("slider/images");

        DirectoryInfo d = new DirectoryInfo(targetDirectory);//get directory folder

        FileInfo[] Files = d.GetFiles("*.jpg");//get all files from Folder

        string str = "";

        foreach (FileInfo file in Files)

        {

            str = str + "" + file.Name + ", ";

        } 

    }