how to open a file selected in listbox ?

Question

I have all the dirctories (2014, 2012), the files of each selected folder (.pdf) in the listbox 2

 

 

 

get the dirctories by this code , 

if (FBD.ShowDialog() == DialogResult.OK)
{
 listBox1.Items.Clear();

 DirectoryInfo[] diri_info =newDirectoryInfo(FBD.SelectedPath).GetDirectories();


 foreach (DirectoryInfo diri in diri_info)
 {

 listBox1.Items.Add(diri);

 }

and i get the files by this code

private void button1_Click(object sender, EventArgs e)
 {

 if (listBox1.SelectedIndex >= 0)
 {

 DirectoryInfo dirictory_choisis = (DirectoryInfo)listBox1.SelectedItem;

 FileInfo[] files = dirictory_choisis.GetFiles();

 listBox2.Items.Clear();
 foreach (FileInfo file in files)
 {

 listBox2.Items.Add(file);


 }

 }
 else
 {
 MessageBox.Show("selectioner un dossier");
 }
 }

Now how I can open the selected file (.pdf)  ?

  

i use this code but dosn't work ( throw an exception file dosn't found) 

private void listBox2_Click(object sender, EventArgs e)
      {

              FileInfo file =(FileInfo) listBox2.SelectedItem;
              Process.Start(file.Name);

      }