OpenFileDialog open = new OpenFileDialog();
open.RestoreDirectory = true;
string fullname = open.FileName;
string path = System.IO.Path.GetDirectoryName(fullname);//路徑
string name = System.IO.Path.GetFileName(fullname);//名稱

OpenFileDialog open = new OpenFileDialog();
open.RestoreDirectory = true;
string fullpath = open.FileName;
//獲取文件路徑和文件名
int index = fullpath.LastIndexOf("http://");  //返回“//”最后一次出現的位置
string filepath = fullpath.Substring(0,index); //截取字符串，0到“//”最后出現的位置
string filename = fullpath.Substring(index+1);  //截取文件名

string fullPath = @"\WebSite1\Default.aspx";

string filename = System.IO.Path.GetFileName(fullPath);//文件名 ?“Default.aspx”
string extension = System.IO.Path.GetExtension(fullPath);//擴展名 “.aspx”
string fileNameWithoutExtension = System.IO.Path.GetFileNameWithoutExtension(fullPath);// 沒有擴展名的文件名 “Default”