Question

I need to know if there is any way to detect in a client PC (Windows) there any PDF reader (Adobe Reader, Foxit Reader, …), using VB6 and. NET (C #).

I can not do by reading the Windows registry, because the user may not have permissions to read it.

Thank you.

Answer 1

A sample based on Jerry Coffin’s suggestion to use FindExecutable (based on this article):

Private Declare Function FindExecutable Lib "shell32.dll" _
  Alias "FindExecutableA"  ( _
  ByVal lpFile As String, _
  ByVal lpDirectory As String, _
  ByVal lpResult As String) As Long 

Private Declare Function lstrlen Lib "kernel32.dll" _
  Alias "lstrlenA" ( _
  ByVal lpString As Any) As Long

' FindExecutable Constants
Private Const ERROR_FILE_NOT_FOUND = 2&
Private Const ERROR_PATH_NOT_FOUND = 3&
Private Const ERROR_BAD_FORMAT = 11&

Private Sub Command1_Click()
  Dim Retval As Long, buffer As String

  ' init buffer 
  buffer = Space(256)

  Retval = FindExecutable("c:\windows\media\tada.wav", "", buffer)

  Select Case Retval
    Case 0
      Debug.Print "Not enough memory to execute this method." 
    Case 31
      Debug.Print "No file association found."
    Case ERROR_FILE_NOT_FOUND
      Debug.Print "File not found."
    Case ERROR_PATH_NOT_FOUND
      Debug.Print "Path not found."
    Case ERROR_BAD_FORMAT
      Debug.Print "The associated application is not a valid Win32 executable."
    Case Else
      Debug.Print "Associated application: " & Left$(buffer, lstrlen(buffer))
  End Select
End Sub