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Microsoft KB Archive/174156

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Knowledge Base


Article ID: 174156

Article Last Modified on 7/1/2004



APPLIES TO

  • Microsoft Visual Basic 6.0 Learning Edition
  • Microsoft Visual Basic 5.0 Learning Edition
  • Microsoft Visual Basic 6.0 Professional Edition
  • Microsoft Visual Basic 5.0 Professional Edition
  • Microsoft Visual Basic 6.0 Enterprise Edition
  • Microsoft Visual Basic 5.0 Enterprise Edition
  • Microsoft Visual Basic 5.0 Control Creation Edition
  • Microsoft Visual Basic 4.0 Standard Edition
  • Microsoft Visual Basic 4.0 Professional Edition
  • Microsoft Visual Basic 4.0 32-Bit Enterprise Edition
  • Microsoft Visual Basic for Applications 5.0



This article was previously published under Q174156

SUMMARY

You can use the Windows API to start the default Internet browser on your system. To do so, you must first determine what Internet browser is registered as the default on your system, and then start that application.

MORE INFORMATION

The following Visual Basic example will launch whatever Internet browser is registered as the default on your system. Obviously, at least one Internet browser must be successfully installed and set up on the system for this to work. Also, since this code is highly dependent on the application-file type associations in the HKEY_CLASSES_ROOT hive of the registry, this can lead to unexpected results and exceptions if the registry is damaged. File types and extensions may also be associated with applications other than the browser. For example, HTM or HTML files may be associated with web development software instead of the browser.

Note that both API functions in the following sample return a value of 32 or less on failure, but the error constants are not included in this article. Full error trapping is recommended for any production use of this technique.

Step-by-Step Example

  1. Start a new project in Visual Basic. Form1 is created by default.
  2. Add a Command button to Form1. Command1 is created by default.
  3. Copy the following code into the Form's module:

           Private Const SW_SHOW = 5       ' Displays Window in its current size
                                          ' and position
          Private Const SW_SHOWNORMAL = 1 ' Restores Window if Minimized or
                                          ' Maximized
    
          Private Declare Function ShellExecute Lib "shell32.dll" Alias _
             "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As _
             String, ByVal lpFile As String, ByVal lpParameters As String, _
             ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long
    
          Private Declare Function FindExecutable Lib "shell32.dll" Alias _
             "FindExecutableA" (ByVal lpFile As String, ByVal lpDirectory As _
             String, ByVal lpResult As String) As Long
    
          Private Sub Command1_Click()
          Dim FileName As String, Dummy As String
          Dim BrowserExec As String * 255
          Dim RetVal As Long
          Dim FileNumber As Integer
    
          ' First, create a known, temporary HTML file
          BrowserExec = Space(255)
          FileName = "C:\temphtm.HTM"
          FileNumber = FreeFile                    ' Get unused file number
          Open FileName For Output As #FileNumber  ' Create temp HTML file
              Write #FileNumber, "<HTML> <\HTML>"  ' Output text
          Close #FileNumber                        ' Close file
          ' Then find the application associated with it
          RetVal = FindExecutable(FileName, Dummy, BrowserExec)
          BrowserExec = Trim(BrowserExec)
          ' If an application is found, launch it!
          If RetVal <= 32 Or IsEmpty(BrowserExec) Then ' Error
              MsgBox "Could not find associated Browser", vbExclamation, _
                "Browser Not Found"
          Else
              RetVal = ShellExecute(Me.hwnd, "open", BrowserExec, _
                "www.microsoft.com", Dummy, SW_SHOWNORMAL)
              If RetVal <= 32 Then        ' Error
                  MsgBox "Web Page not Opened", vbExclamation, "URL Failed"
              End If
          End If
          Kill FileName                   ' delete temp HTML file
          End Sub
                            
  4. Press the F5 key to run the project. Click on Command1 and your default Internet Browser will start.


REFERENCES

For more information, please Search on the following topics in either the Win32 Programmer's Reference or The Microsoft Developer Network (MSDN) Library CD-ROM:

  • ShellExecute
  • FindExecutable



Additional query words: IE Internet Explorer Netscape Navigator kbVBp500 kbVBp600 kbVBp kbdsd kbDSupport kbVBp400 kbVBA500 kbInternet Communicator KBWIN32SDK KBAPI

Keywords: kbhowto kbgrpdsvb KB174156