DOCUMENT:Q174050 11-JAN-2001 [vbwin] TITLE :HOWTO: Determine File Type from Registered CLSID PRODUCT :Microsoft Visual Basic for Windows PROD/VER: OPER/SYS: KEYWORDS:kbGrpDSVB ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual Basic Learning Edition for Windows, version 6.0 - Microsoft Visual Basic Professional Edition for Windows, version 6.0 - Microsoft Visual Basic Enterprise Edition for Windows, version 6.0 - Microsoft Visual Basic Control Creation Edition for Windows, version 5.0 - Microsoft Visual Basic Learning Edition for Windows, version 5.0 - Microsoft Visual Basic Professional Edition for Windows, version 5.0 - Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 - Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 - Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 - Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 ------------------------------------------------------------------------------- SUMMARY ======= You can use the Windows API to retrieve the CLSID (class ID) associated with a given file and use this value to determine the product and version of its format. MORE INFORMATION ================ The CLSID for a product or component can be found in the Windows Registry under HKEY_CLASSES_ROOT. For example: MyComputer\HKEY_CLASSES_ROOT\Excel.Sheet.8\CLSID The following example creates a Visual Basic project that shows how to retrieve and use the CLSID associated with a given file. Constants are only defined for two versions of Microsoft Excel and two versions of Microsoft Word to demonstrate this technique. This example can be modified to work for any file format with a unique CLSID associated with it. NOTE: In order to identify a file on a given system, the appropriate CLSID must be registered on the system running this code. Also, this sample does not include any error trapping, which should be added for any production use of this technique. Step-by-Step Example -------------------- 1. Start a new Standard EXE project. Form1 is created by default. 2. Add a Command button, a TextBox, and two Labels to Form1. 3. Copy the following code into the Form's module: Private Sub Command1_Click() Dim FileCLSID As String FileCLSID = GetCLSID(Text1.Text) Label2.Caption = FileCLSID Select Case FileCLSID Case EXCEL97 Label1.Caption = "Excel 97" Case EXCEL95 Label1.Caption = "Excel 95" Case WORD97 Label1.Caption = "Word 97" Case WORD95 Label1.Caption = "Word 95" Case Else Label1.Caption = "Unknown File Version" End Select End Sub Private Sub Form_Load() Label1.AutoSize = True Label2.AutoSize = True End Sub 4. Add a Module to the project. In Visual Basic 4, choose "Module" from the "Insert" menu. In later versions of Visual Basic, choose "Add Module" from the "Project" menu. 5. Copy the following code into Module1: Type GUID B(16) As Byte End Type Declare Function GetClassFile Lib "Ole32.DLL" (ByVal lpszFileName _ As String, ByRef pclsid As GUID) As Long Declare Function StringFromGUID2 Lib "Ole32.DLL" (ByRef rguid _ As GUID, ByVal lpsz As String, ByVal cbMax As Long) As Long Public Const EXCEL97 As String = _ "{00020820-0000-0000-C000-000000000046}" Public Const EXCEL95 As String = _ "{00020810-0000-0000-C000-000000000046}" Public Const WORD97 As String = _ "{00020906-0000-0000-C000-000000000046}" Public Const WORD95 As String = _ "{00020900-0000-0000-C000-000000000046}" Function GetCLSID(FileName As String) As String Dim g As GUID Dim RetVal As Long Dim strGUID As String RetVal = GetClassFile(StrConv(FileName, vbUnicode), g) strGUID = Space(255) RetVal = StringFromGUID2(g, strGUID, 255) strGUID = StrConv(strGUID, vbFromUnicode) If (InStr(strGUID, Chr(0)) > 0) Then strGUID = Left(strGUID, InStr(strGUID, Chr(0)) - 1) End If GetCLSID = strGUID End Function 6. Run the project and enter a path and filename for a Word 97 or Word 95 document, or an Excel 97 or Excel 95 Worksheet into Text1. Click on Command1 and the type of file will be displayed in Label1 and the actual CLSID will be displayed in Label2. 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: - GetClassFile - StringFromGUID2 - CLSID (class ID) Additional query words: kbVBp kbdsd kbDSupport kbRegistry kbVBp400 kbVBp500 kbVBp600 kbAPI ====================================================================== Keywords : kbGrpDSVB Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500Search kbVBA500 kbVBA600 kbVB500 kbVB600 kbVB400Search kbVB400 kbZNotKeyword3 Issue type : kbhowto ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.