In a previous article entitled "WebLink: What is it anyway?", I discussed Pro/WebLink and how it's not exactly a Javascript interface. Now it's the VB API's turn. The VB API is newly released by PTC with Wildfire 4. It is billed as a Visual Basic interface to PTC's PFC libraries, which is the same core that J-Link and Pro/WebLink are built upon.
While this is true, it's not that limited. Don't let the name scare you away from using your favorite COM accessible programming or scripting language to write Pro/Engineer applications. This is a good thing because it opens the API to a much wider range of applications.
In this article, I'll walk through sample applications written in Visual Basic, VBScript (using Windows Script Host), Perl, and Javascript (in a HyperText Application), all using the VB API. The sample application will connect to a Pro/Engineer session, obtain the session object, display the name of the current model, then disconnect from the Pro/Engineer session. Each program will display the model name in a different way.
Suggested reading is the section on the importance of disconnecting from Pro/Engineer in Pro/E VB API: A First Look.
Excel Macro
This is the standard and documented approach to the sample program. Objects are declared up front, the connection to Pro/Engineer is made, then the session object is obtained. The model name is displayed both in cell A1 and in a MsgBox.
Sub Macro1()
Dim asynconn As New pfcls.CCpfcAsyncConnection
Dim conn As pfcls.IpfcAsyncConnection
Dim session As pfcls.IpfcBaseSession
Dim mdlname
Set conn = asynconn.Connect("", "", ".", 5)
Set session = conn.session
mdlname = session.CurrentModel.Filename
Range("A1").Select
ActiveCell.FormulaR1C1 = mdlname
MsgBox ("Name: " & mdlname)
conn.Disconnect(2)
End Sub
VBScript
The VBScript code is almost identical except that VBScript doesn't seem to allow for the type declaration of the objects. As a result, the CreateObject() call is used to instantiate a pfcAsyncConnection object.
The program is executed using the following command line:
cscript vbapi_script.vbs
Dim asynconn
Dim conn
Dim session
Dim mdlname
Set asynconn = CreateObject("pfcls.pfcAsyncConnection")
Set conn = asynconn.Connect("", "", ".", 5)
Set session = conn.session
mdlname = session.CurrentModel.Filename
MsgBox ("Name: " & mdlname)
conn.Disconnect(2)
Perl
As with most COM applications, the Perl syntax is also very similar to the VBScript code, but with Perl's own syntactical flavor. Win32::OLE->new() is the Perl equivalent to VBScript's CreateObject(). The Perl program outputs the model name to the command prompt (or standard output).
use Win32::OLE;
$asynconn = Win32::OLE->new("pfcls.pfcAsyncConnection");
$conn = $asynconn->Connect( "", "", ".", 5 );
$session = $conn->Session;
$mdlName = $session->CurrentModel->FileName;
print "mdlName: $mdlName", "\n";
$conn->Disconnect(2);
Javascript
Pro/WebLink applications can finally break out of the embedded browser jail using the VB API. This example uses a "Hypertext Application", which is a web page with a special HTA tag and with a file extension of ".hta" instead of ".htm". The pfcUtils.js file cannot be used as-is because it tries to use COM objects with "pfc." prefixes, instead of those associated with VB API which have "pfcls." prefixes.
Other than those differences, it's essentially a Pro/WebLink application. As with the other examples, because it's an asynchronous application, the code must connect to the Pro/Engineer session. This is a step that embedded browser based Pro/WebLink applications don't have to worry about.
<html>
<head>
<title>VB API Test</title>
<HTA:APPLICATION
ID="vbapi-test"
APPLICATIONNAME="VB API Test"
SCROLL="auto"
SINGLEINSTANCE="yes"
>
</head>
<body>
<SCRIPT LANGUAGE="JavaScript">
function HitMe ( ) {
var obj = null;
var elem = document.getElementById("mesg");
if (obj == null) {
try {
obj = new ActiveXObject("pfcls.pfcAsyncConnection");
}
catch (e) {
elem.innerHTML = "Failed to create object";
return;
}
}
var conn = obj.Connect( "", "", ".", 5 );
var session = conn.Session;
var mdlName = session.CurrentModel.FileName;
elem.innerHTML = "mdlName: " + mdlName;
conn.Disconnect(2);
}
</SCRIPT>
<form name="f">
<INPUT name="a" type=button value="Hit me!" onclick="HitMe()">
<br><a id="mesg"></a><br>
</form>
</body>
</html>
These are just a few of the possibilities. As you can see, there is nothing really Visual Basic specific about the VB API. It's just an API.
