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• Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 32-bit only, for Windows, version 4.0

SUMMARY

You can use the Windows API ShellExecute() function to start the application associated with a given document extension without knowing the name of the associated application. For example, you could start the Paintbrush program by passing the filename ARCADE.BMP to the ShellExecute() function.

MORE INFORMATION

The ShellExecute function opens or prints the specified file. Following is the declaration to use when calling this function from Visual Basic:

   Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" _
                   (ByVal hwnd As Long, ByVal lpszOp As String, _
                    ByVal lpszFile As String, ByVal lpszParams As String, _
                    ByVal LpszDir As String, ByVal FsShowCmd As Long) _
                    As Long 

Parameter     Description
----------------------------------------------------------------------------
hwnd          Identifies the parent window. This window receives any
              message boxes an application produces (for example, for error
              reporting).

lpszOp        Points to a null-terminated string specifying the operation
              to perform. This string can be "open" or "print." If this
              parameter is NULL, "open" is the default value.

lpszFile      Points to a null-terminated string specifying the file
              to open.

lpszParams    Points to a null-terminated string specifying parameters
              passed to the application when the lpszFile parameter
              specifies an executable file. If lpszFile points to a string
              specifying a document file, this parameter is NULL.

LpszDir       Points to a null-terminated string specifying the default
              directory.

FsShowCmd     Specifies whether the application window is to be shown when
              the application is opened. 

Step-by-Step Example

1. Start a New project in Visual Basic. Form1 is created by default.
   
   
2. Add the following code to the General Declarations section of Form1:
   

         Option Explicit
   
         Private Declare Function ShellExecute Lib "shell32.dll" Alias _
         "ShellExecuteA" (ByVal hwnd As Long, ByVal lpszOp As _
         String, ByVal lpszFile As String, ByVal lpszParams As String, _
         ByVal lpszDir As String, ByVal FsShowCmd As Long) As Long
   
         Private Declare Function GetDesktopWindow Lib "user32" () As Long
   
         Const SW_SHOWNORMAL = 1
   
         Const SE_ERR_FNF = 2&
         Const SE_ERR_PNF = 3&
         Const SE_ERR_ACCESSDENIED = 5&
         Const SE_ERR_OOM = 8&
         Const SE_ERR_DLLNOTFOUND = 32&
         Const SE_ERR_SHARE = 26&
         Const SE_ERR_ASSOCINCOMPLETE = 27&
         Const SE_ERR_DDETIMEOUT = 28&
         Const SE_ERR_DDEFAIL = 29&
         Const SE_ERR_DDEBUSY = 30&
         Const SE_ERR_NOASSOC = 31&
         Const ERROR_BAD_FORMAT = 11&
   
         Function StartDoc(DocName As String) As Long
             Dim Scr_hDC As Long
             Scr_hDC = GetDesktopWindow()
             StartDoc = ShellExecute(Scr_hDC, "Open", DocName, _
             "", "C:\", SW_SHOWNORMAL)
         End Function
   
         Private Sub Form_Click()
             Dim r As Long, msg As String
             r = StartDoc("C:\WINDOWS\ARCADE.BMP")
             If r <= 32 Then
                 'There was an error
                 Select Case r
                     Case SE_ERR_FNF
                         msg = "File not found"
                     Case SE_ERR_PNF
                         msg = "Path not found"
                     Case SE_ERR_ACCESSDENIED
                         msg = "Access denied"
                     Case SE_ERR_OOM
                         msg = "Out of memory"
                     Case SE_ERR_DLLNOTFOUND
                         msg = "DLL not found"
                     Case SE_ERR_SHARE
                         msg = "A sharing violation occurred"
                     Case SE_ERR_ASSOCINCOMPLETE
                         msg = "Incomplete or invalid file association"
                     Case SE_ERR_DDETIMEOUT
                         msg = "DDE Time out"
                     Case SE_ERR_DDEFAIL
                         msg = "DDE transaction failed"
                     Case SE_ERR_DDEBUSY
                         msg = "DDE busy"
                     Case SE_ERR_NOASSOC
                         msg = "No association for file extension"
                     Case ERROR_BAD_FORMAT
                         msg = "Invalid EXE file or error in EXE image"
                     Case Else
                         msg = "Unknown error"
                 End Select
                 MsgBox msg
             End If
         End Sub 

   
   
   
3. Run the project and click the form.
   
   

General Information About the Process

REFERENCES

"Programmer's Reference, Volume 2: Functions" of the Microsoft Windows Software Development Kit (SDK), pages 901-904

Additional query words: kbVBp500 kbVBp600 kbVBp kbdsd kbDSupport kbVBp400 KBWIN32SDK KBAPI

Keywords : kbGrpVB
Issue type : kbhowto
Technology :

Article ID: Q170918

Last Reviewed:
February 16, 2000

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