FILE: Programmatically Retrieve the Members of a DLL Class

• Microsoft Visual Basic Professional and Enterprise Editions for Windows, version 5.0

SUMMARY

This article shows you how to programmatically retrieve the class names and members of a dll or ActiveX file that contains a type library. You can get this information by using the Object Browser in Visual Basic or you can programmatically retrieve this information. The sample program uses an unsupported file Tlbinf32.dll to retrieve some of the type library information, but is not a complete substitute for the Object Browser.

NOTE: The file Tlbinf32.dll is not supported by Microsoft Technical Support either electronically or via telephone. This file is subject to change without notice.

A Visual Basic project that demonstrates how to use this file to get the class names and members from a dll or ActiveX controls is available for download from the Microsoft Software Library:

 ~ Clsnmmbr.exe (size: 20335 bytes) 

   ARTICLE-ID: Q119591
   TITLE     : How to Obtain Microsoft Support Files from Online Services

MORE INFORMATION

The Object Browser in Visual Basic shows you the collections and member names of a dll class. You may want to develop an add-in for use in other development environments that has the same functionality as the object browser and to add some automation capabilities. This sample shows you how to retrieve this information programmatically by using the file tlbinf32.dll. This file is stored in the OS\System directory of your installation disk and is copied to your computer's system folder during the Visual Basic installation.

After downloading and running the self-extracting file, the following files are extracted to your hard drive:

• From1.frm (4K)
• Form1.frx (1K)
• Project1.vbp (1K)
• Project1.vbw (1K)
• Readme.txt

You can duplicate this project by completing the steps shown in the following section.

Step-by-Step Example

1. Start Visual Basic and chose Standard Exe or, if Visual Basic is already running, choose New Project from the File menu.

2. Set a reference to the file Tlbinf32.dll by completing the following steps:

   a. From the Project menu, click References. The References dialog box

         is displayed.
   

   b. From the References dialog box, click Browse.

   c. From your Windows system directory, select the file Tlbinf32.dll.

3. Add the following controls to the Form1 form and set the indicated properties:

      Control               Property Name             Property Setting
      ----------------------------------------------------------------
      Command Button        Name                      Command1
                            Caption                   Choose File
                            Height                    495
                            Left                      4800
                            TabIndex                  3
                            Top                       720
                            Width                     1815
   
      Command Button        Name                      Command2
                            Caption                   End
                            Height                    495
                            Left                      4800
                            TabIndex                  4
                            Top                       1320
                            Width                     1815
   
      Text Box              Name                      Text1
                            Height                    375
                            Left                      1080
                            TabIndex                  1
                            Top                       120
                            Width                     5535
   
      List Box              Name                      List1
                            Height                    2205
                            Left                      120
                            Top                       720
                            Width                     4455
   
      Common Dialog         Name                      CommonDialog1
   
      Label                 Name                      Label1
                            Caption                   Selected DLL
                            Height                    375
                            Left                      0
                            TabIndex                  2
                            Top                       120
                            Width                     1095
   
   

4. Copy and paste the following code to the Code window of the Form1 form.

         Private Sub Form_Load()
             strFilter = "DLL Files (*.dll)|*.dll|"
             strFilter = strFilter & "OCX Files (*.ocx)|*.ocx|"
             strFilter = strFilter & "All Files (*.*)|*.*"
             CommonDialog1.Filter = strFilter
         End Sub
   
         Private Sub Command1_Click()
             Dim x As TypeLibInfo
             Dim y As CoClasses
             Dim z As Interfaces
             Dim w As Members
             Dim u As MemberInfo
             Dim i As Integer, j As Integer, n As Integer, k As Integer
             Dim strFilter As String
             Dim strName As String, strMembers As String
   
             On Error Resume Next
             CommonDialog1.ShowOpen
             List1.Clear
             Text1.Text = ""
   
             'Program ends if you click the Cancel button in the
             'file open dialog box
             If CommonDialog1.Flags = 0 Then
                 End
             End If
   
             'Get information from type library
             Set x = TypeLibInfoFromFile(CommonDialog1.filename)
             Set y = x.CoClasses
   
             'Show Type Library information in the List box
             For i = 1 To y.Count
                 If i <> 1 Then
                     strName = ""
                     List1.AddItem strName
                 End If
                 strName = "Class Name: " & y.Item(i).Name
                 List1.AddItem strName
                 Set z = y.Item(i).Interfaces
                 For n = 1 To z.Count
                     Set w = z.Item(n).Members
                     For k = 1 To w.Count
                         Set u = w.Item(k)
                         strMembers = "      Member: " & u.Name
                         List1.AddItem strMembers
                     Next
                 Next
             Next
             Set z = Nothing
             Set y = Nothing
             Set x = Nothing
             Set w = Nothing
   
             'Display filename in the text box
             Text1.Text = CommonDialog1.filename
   
             'If the file does not contain type library information
             'then display this error message.
             If Err.Number = 91 Then
                 Dim strMsgTitle As String, strMsgError As String
                 Dim intResponse
                 strMsgTitle = "No Type Library"
                 strMsgError = "You chose a file without a type library. "
                 strMsgError = strMsgError & "Choose another file."
                 Err.Clear
                 intResponse = MsgBox(strMsgError, vbOKCancel, strMsgTitle)
   
                 If intResponse = vbOK Then
                     Command1_Click
                 End If
   
             End If
   
         End Sub
   
         Private Sub Command2_Click()
             End
         End Sub
   
   

5. Press the F5 key to run the program. Select a .dll or an ActiveX control file. If the file contains a type library, the class names and members are displayed in the list box.

Keywords          : vb5all VBKBWinAPI kbsample
Version           : WINDOWS:5.0
Platform          : WINDOWS
Solution Type     : kbfile