How to Modify VISDATA Sample to Work with Compatibility Layer

MORE INFORMATION

1. Start a new project in Visual Basic. Form1 is created by default.
2. Load the VISDATA.MAK sample application located in the \VB\SAMPLES\VISDATA directory.
3. Select the VDMDI.FRM from the project window, and bring this form into view.
4. Press the F7 key to view the code, and find the MDIForm_Load event procedure in VDMDI.FRM.
5. Make the following modifications to the code. In the load event, look for the following comment:

      'write ISAM entries in INI file just in case
   						

   Immediately following this comment, you'll find a series of lines of the following form:

      x = OSWritePrivateProfileString("Installable ISAMs", ...
   						

   The third argument in each of these calls is a file name. Modify the name so that it contains the number 200 instead of 110. For example, change XBS110.DLL into XBS200.DLL. Also, add an extra line to support Paradox 4.X. The resulting code should look like the following except that each pair of lines will appear as one, single line in Visual Basic:

      x = OSWritePrivateProfileString("Installable ISAMS", "Paradox 3.X",
      "PDX200.DLL", "VISDATA.INI")
      x = OSWritePrivateProfileString("Installable ISAMS", "Paradox 4.X",
      "PDX200.DLL", "VISDATA.INI")
      x = OSWritePrivateProfileString("Installable ISAMS", "dBASE III",
      "XBS200.DLL", "VISDATA.INI")
      x = OSWritePrivateProfileString("Installable ISAMS", "dBASE IV",
      "XBS200.DLL", "VISDATA.INI")
      x = OSWritePrivateProfileString("Installable ISAMS", "FoxPro 2.0",
      "XBS200.DLL", "VISDATA.INI")
      x = OSWritePrivateProfileString("Installable ISAMS", "FoxPro 2.5",
      "XBS200.DLL", "VISDATA.INI")
      x = OSWritePrivateProfileString("Installable ISAMS", "Btrieve",
      "BTRV200.DLL", "VISDATA.INI")
   						

   Add the following entries to support Paradox on a network:

      x = OSWritePrivateProfileString("Paradox ISAM", "ParadoxUserName",
      "Bill", "VISDATA.INI")
      ' NOTE: Bill is the machine name (any name you want to give it)
      x = OSWritePrivateProfileString("Paradox ISAM", "ParadoxNetPath",
      "c:\vb\prdx", "VISDATA.INI")
      x = OSWritePrivateProfileString("Paradox ISAM", "ParadoxNetStyle",
      "4.x", "VISDATA.INI") '** note: 4.x works with 3.x and 4.x NetStyles
      x = OSWritePrivateProfileString("Paradox ISAM", "CollatingSequence",
      "Ascii", "VISDATA.INI")
   						

   Further down in the code (about half way through the Sub procedure), you will see this line:

      If PrefOpenOnStartup.Checked = True Then
   						

   Add an extra If statement to support the shortcut key for Paradox 4.x to make the code look like this:

      If PrefOpenOnStartup.Checked = True Then
         If gstDataType = "MS Access" Then
            SendKeys "%FOM"
         ElseIf gstDataType = "dBASE III" Then
            SendKeys "%FOD"
         ElseIf gstDataType = "dBASE IV" Then
            SendKeys "%FOA"
         ElseIf gstDataType = "FoxPro 2.0" Then
            SendKeys "%FOF"
         ElseIf gstDataType = "FoxPro 2.5" Then
            SendKeys "%FOX"
         ElseIf gstDataType = "Paradox 3.X" Then
            SendKeys "%FOP"
         ElseIf gstDataType = "Paradox 4.X" Then   '** new addition
            SendKeys "%FOR"   '** 'r' in the word Paradox is shortcut
         ElseIf gstDataType = "Btrieve" Then
            SendKeys "%FOB"
         ElseIf gstDataType = "ODBC" Then
            SendKeys "%BOB"
         End If
      End If
   						

6. Add new lines of code to the OpenLocalDB procedure in the VDMDI.FRM form's general section. Look for the Select Case statement, and modify it to look like this:

      Select Case gstDataType
         Case "MS Access"
            CMD1.Filter = "Access DBs (*.mdb)|*.mdb|All Files (*.*)|*.*"
            CMD1.DialogTitle = "Open MS Access Database"
         Case "dBASE III"
            CMD1.Filter = "dBASE III DBs (*.dbf)|*.dbf"
            CMD1.DialogTitle = "Open dBASE III Database"
         Case "dBASE IV"
            CMD1.Filter = "dBASE IV DBs (*.dbf)|*.dbf"
            CMD1.DialogTitle = "Open dBASE IV Database"
         Case "FoxPro 2.0"
            CMD1.Filter = "FoxPro DBs (*.dbf)|*.dbf"
            CMD1.DialogTitle = "Open FoxPro 2.0 Database"
         Case "FoxPro 2.5"
            CMD1.Filter = "FoxPro DBs (*.dbf)|*.dbf"
            CMD1.DialogTitle = "Open FoxPro 2.5 Database"
         Case "Paradox 3.X"
            CMD1.Filter = "Paradox DBs (*.db)|*.db"
            CMD1.DialogTitle = "Open Paradox 3.X Database"
         Case "Paradox 4.X"             '** newly added for Paradox 4.x
            CMD1.Filter = "Paradox DBs (*.db)|*.db"
            CMD1.DialogTitle = "Open Paradox 4.X Database"
         Case "Btrieve"
            CMD1.Filter = "Btrieve DBs (FILE.DDF)|FILE.DDF"
            CMD1.DialogTitle = "Open Btrieve Database"
      End Select
   						

   Further down in the code there is another Select Case statement. Make it look like this:

      Select Case gstDataType
         Case "dBASE III"
            Connect = "dBASE III"
            DataBaseName = StripFileName(gstDBName)
         Case "dBASE IV"
            Connect = "dBASE IV"
            DataBaseName = StripFileName(gstDBName)
         Case "FoxPro 2.0"
            Connect = "FoxPro 2.0"
            DataBaseName = StripFileName(gstDBName)
         Case "FoxPro 2.5"
            Connect = "FoxPro 2.5"
            DataBaseName = StripFileName(gstDBName)
         Case "Paradox 3.X"
            Connect = "Paradox 3.X"
            DataBaseName = StripFileName(gstDBName)
         Case "Paradox 4.X"               '** newly added
            Connect = "Paradox 4.X"
            DataBaseName = StripFileName(gstDBName)
         Case "Btrieve"
            Connect = "Btrieve;"
            DataBaseName = gstDBName
         Case Else
            Connect = ""
            DataBaseName = gstDBName
      End Select
   						

7. Choose Menu Design Window from the Window menu, while the VDMDI.FRM is showing. A code window cannot be showing or the Menu Design Window option is grayed-out.
8. Select the --------&Btrieve... line under the ----&Open DataBase... section, and choose the Insert button. Type Pa&radox 4.X... as the caption and Open_paradox4x as the name. Then add the following code to the Open_paradox4x_Click event procedure:

      Sub Open_paradox4X_Click ()
         gstDataType = "Paradox 4.X"
         OpenLocalDB False
      End Sub
   						

9. Select the --------&Btrieve... line under the ----&New... section and choose the Insert button. Enter Pa&radox 4.X... as the caption and New_paradox4x as the name. Then add the following code to the New_paradox4x_Click event procedure:

      Sub New_paradox4X_Click ()
         gstDataType = "Paradox 4.X"
         NewLocalISAM
      End Sub
   						

The VISDATA sample application will now work with the Microsoft Access version 2.0 database engine.

NOTE: If you run VISDATA without making the changes outlined in this article, you will receive the following error message if you try to connect to a dBASE file: