using System.IO;
string fileName;
String extendedName;
String fileName1;
private void button1_Click(object sender, EventArgs e)
{
OpenFileDialog ofd = new OpenFileDialog(); //new一个方法
ofd.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments); //定义打开的默认文件夹位置
ofd.ShowDialog(); //显示打开文件的窗口
fileName = ofd.FileName; //获得选择的文件路径
extendedName = Path.GetExtension(fileName); //获得文件扩展名
fileName1 = Path.GetFileName(fileName);
}