open file after find it with FileInfo

Question

1 ) i read the part about (Working with FileInfo and DirectoryInfo classes) . but i don't find a function to open the specific file by comparing his name with the name on textbox ,

how can i open a file however his extension ?

if (diri_info.Name == textBox1.Text)

{

{

foreach (FileInfo file in files_info)

{

 // open this file

listBox1.Items.Add(file.Name);

}

}

 

 

 

 

 

2) how can i get name for all files on 4 Directory on one specific Directory  ?

think you !