opening file in treeview

Question

i have used this code, but i am getting 'System.ComponentModel.Win32Exception' occurred in System.dll exception. 

 

string path = dir + treeView1.SelectedNode.FullPath;

MessageBox.Show(path);

System.Diagnostics.Process.Start(path);

 

plz help me how i remove this exception and my file get open on click