Question

I am using the function below to open the user’s default web browser.

 Public Function ShowHelp(ByVal url As String) As System.Diagnostics.Process
    Dim startInfo As New Diagnostics.ProcessStartInfo()
    startInfo.FileName = url
    startInfo.WindowStyle = ProcessWindowStyle.Maximized
    Return System.Diagnostics.Process.Start(startInfo)
 End Function

A couple of times the function returned the error (on users machine) “the system cannot find the file specified”

I guess the user has not set a default web browser.
Why i get this error? How could i add a default web browser check before calling this function?

Answer 1

This is in C#, but this is a good article:

http://ryanfarley.com/blog/archive/2004/05/16/649.aspx

Here’s the C# as VB.NET:

Private Function getDefaultBrowser() As String
    Dim browser As String = String.Empty
    Dim key As RegistryKey = Nothing
    Try
        key = Registry.ClassesRoot.OpenSubKey("HTTP\shell\open\command", False)

        'trim off quotes
        browser = key.GetValue(Nothing).ToString().ToLower().Replace("""", "")
        If Not browser.EndsWith("exe") Then
            'get rid of everything after the ".exe"
            browser = browser.Substring(0, browser.LastIndexOf(".exe") + 4)
        End If
    Finally
        If key IsNot Nothing Then
            key.Close()
        End If
    End Try
    Return browser
End Function