I am working in the dark. There is an application installed on my PC by the corporate fathers that allows programmatic access to a library of reports. I can't get anyone to tell me the application's properties or methods (apart from a couple methods found in some scripts....)
I'm using Access VBA to get to the application, and it does load it up (it shows a GUI when the CreateObject() statement is executed.)
How can I get it to list its properties and methods once I invoke it? You can see my effort, but it fails saying "Object doesn't support this property or method" when it executes the "for each" statement.
Sub StartDataNav()
Set oleDataNav = CreateObject("DataNavigator.Application")
Dim p As Object
For Each p In oleDataNav.Properties
Next p
End Sub
If need be, I can change to C#.net, but I'm not as experienced invoking what I assume is a non-managed application....
You can use the TlbInf32.dll (TLI) to inspect the public members of the target application. http://msdn.microsoft.com/en-us/magazine/bb985086.aspx seems to be a good start.
Or just inspect TLI itself using the object browser (after referencing it in the VBE).
Put a breakpoint on your line
Dim p As Object
and open the locals window (View --> Locals).
This will let you see all the properties of your object by expanding the oleDataNav object in the locals window.
Related
This question already has answers here:
How to use GetObject in VBScript
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Closed 3 years ago.
I recently got a small CG software package from my friend his father wrote about 30 years ago. It has a window where one can create and render some solid primitives. Interestingly, it has a VBA interface and I can in Excel (let’s call it TheSoftware) use Set app = CreateObject(“TheSoftware.Application”) to create such application (after setting app.Visible to True one can get the window on the screen)! However, the GetObject(, “TheSoftware.Application”) returns the “ActiveX component can’t create object” error. More surprisingly to me, the GetObject(“”, “TheSoftware.Application”) successfully creates the application! I have its source code in C++ about 900 KB that I can share, but just to be quick, has anyone had this issue before, or have a clue what may be the issue? I am no expert in C++, and the author passed away 4 years ago. I have seen the “opposite” problem of failing to create an object but OK when getting it, but not this one. Any idea is welcome, thanks!
GetObject(FName) opens a file or connects to a file if it already opened (and if class is specified use that class to open it) OR GetObject(,"Appname") connects to a running instance of an application. You are creating a blank file.
Visual Basic Scripting Edition
GetObject Function
See Also CreateObject Function
Requirements
Version 5
Returns a reference to an Automation object from a file.
GetObject([pathname] [, class])
Arguments
pathname
Optional; String. Full path and name of the file containing the object to retrieve.
If pathname is omitted, class is required.
class
Optional; String. Class of the object.
The class argument uses the syntax appname.objectype and has these
parts:
Use the GetObject function to access an Automation object from a file
and assign the object to an object variable. Use the Set statement to
assign the object returned by GetObject to the object variable. For
example:
Dim CADObject
Set CADObject = GetObject("C:\CAD\SCHEMA.CAD")
When this code is executed, the application associated with the
specified pathname is started and the object in the specified file is
activated. If pathname is a zero-length string (""), GetObject
returns a new object instance of the specified type. If the pathname
argument is omitted, GetObject returns a currently active object of
the specified type. If no object of the specified type exists, an
error occurs.
Some applications allow you to activate part of a file. Add an
exclamation point (!) to the end of the file name and follow it with a
string that identifies the part of the file you want to activate. For
information on how to create this string, see the documentation for
the application that created the object.
For example, in a drawing application you might have multiple layers
to a drawing stored in a file. You could use the following code to
activate a layer within a drawing called SCHEMA.CAD:
Set LayerObject = GetObject("C:\CAD\SCHEMA.CAD!Layer3")
If you don't specify the object's class, Automation determines the application to start and the object to activate, based on the file
name you provide. Some files, however, may support more than one class
of object. For example, a drawing might support three different types
of objects: an Application object, a Drawing object, and a Toolbar
object, all of which are part of the same file. To specify which
object in a file you want to activate, use the optional class
argument. For example:
Dim MyObject
Set MyObject = GetObject("C:\DRAWINGS\SAMPLE.DRW", "FIGMENT.DRAWING")
In the preceding example, FIGMENT is the name of a drawing application
and DRAWING is one of the object types it supports. Once an object is
activated, you reference it in code using the object variable you
defined. In the preceding example, you access properties and methods
of the new object using the object variable MyObject. For example:
MyObject.Line 9, 90
MyObject.InsertText 9, 100, "Hello, world."
MyObject.SaveAs "C:\DRAWINGS\SAMPLE.DRW"
Note Use the GetObject function when there is a current instance
of the object or if you want to create the object with a file already
loaded. If there is no current instance, and you don't want the
object started with a file loaded, use the CreateObject function.
If an object has registered itself as a single-instance object, only
one instance of the object is created, no matter how many times
CreateObject is executed. With a single-instance object, GetObject
always returns the same instance when called with the zero-length
string ("") syntax, and it causes an error if the pathname argument is
omitted.
Requirements Version 5
See Also CreateObject Function
© 2001 Microsoft Corporation. All rights reserved.
Build: Topic Version 5.6.9309.1546
Also these are the COM API calls that each form makes. From the Automation part of the COM docs.
CreateObject (“ProgID”)
CLSIDFromProgID
CoCreateInstance
QueryInterface to get IDispatch interface.
GetObject (“filename”, “ProgID”)
CLSIDFromProgID
CoCreateInstance
QueryInterface for IPersistFile interface.
Load on IPersistFile interface.
QueryInterface to get IDispatch interface.
GetObject (“filename”)
CreateBindCtx creates the bind context for the subsequent functions.
MkParseDisplayName returns a moniker handle for BindMoniker.
BindMoniker returns a pointer to the IDispatch interface.
Release on moniker handle.
Release on context.
GetObject (“ProgID”)
CLSIDFromProgID
GetActiveObject on class ID.
QueryInterface to get IDispatch interface.
Dim x As New interface
Find CLSID for interface.
CoCreateInstance
QueryInterface
I am writing a VBA application, and for a specific function, I am using only late-binding, as most of the users of the application won't have the reference installed (and won't use this specific function).
The object I am using behaves like:
class PISDK{
PIServer GetServer(string hostName)
}
The GetServer method returns a PIServer object, but a more specific interface exists, implementing PIServer:
interface IGetPoints2 : PIServer{}
I would like to downcast the PIServer object to a IGetPoints2 object.
Without doing anything, I get a PIServer object:
Dim PiSdk As Object
Dim PiServer As Object
Set PiSdk = CreateObject("PISDK.PISDK")
Set PiServer = PiSdk.GetServer("foo")
Looking at PiServer in the debugger confirms that.
Using a strongly typed variable should work, but I do not want to reference any of the types used here.
How can I downcast this object using late-binding only?
Please read this:
As you are not adding a reference to the PI SDK Type Library, I
believe you cannot use "rtInterpolated" as the second parameter of
the ArcValue method; instead, you can use the corresponding number
(which is 3 for "rtInterpolated" in the RetrievalTypeConstants
enumeration).
VBA with late binding is tricky with optional
parameters, as we cannot omit them when calling a method. Instead,
you need to use either Nothing (in case the optional parameter is
an object) or "" (in case the optional parameter is a string) as
"parameter placeholders" (by the way, the same happens in
VBScript, a scripting language for scripts contained in files with
.vbs extension that run independently from any application).
able to put some functional sample code together, which is more
complete and will hopefully help you.
I've created a spreadsheet which optionally uses Bloomberg data pulled using the API COM 3.5 Type Library. I want to be able to distribute that spreadsheet to non-Bloomberg users, but they can't run it since they don't have the right libraries.
All blpapi-related code besides what's in the Class Module is behind if statements that should not be entered by the non-BB users. In the class module, I lazily define the session and Service so that the blpapi-specific definitions are delayed until the class initializes (see below):
Option Explicit
Private session As Object
Dim refdataservice As Object
Private Sub Class_Initialize()
' First create session.
Set session = New blpapicomLib2.session
session.QueueEvents = True
session.Start
' Then open service.
' A service provides the schemas needed to make requests.
session.OpenService "//blp/refdata"
Set refdataservice = session.GetService("//blp/refdata")
End Sub
In short - the code which appears to be causing the issues never runs. My (very limited) understanding of VBA is mostly functional, so I'm probably missing something obvious. Is this a compilation-related error? Is there a way for me to precompile the VBA so users don't experience this issue? Maybe some type of error handling method so the workbook doesn't hang?
Here was my solution for my own problem:
I had two functions with inputs that used library-specific types. I converted those to generic objects (using late binding on the session and refdataservice was not enough). Then, I unselected the bbcom library, and added a dynamic reference to the dll file in Workbook_Open(). Even if the load fails, the error is able to be caught, whereas before excel would have to be killed. This is still a problem if the user tries to use part of the workbook that uses the BB-related code, but this can be mitigated in a few different ways.
The setup
I'm developing and maintaining an Excel add-in that comes with its own tab of controls within Excel's Ribbon UI. I've come across the problem of state loss before (meaning loss of all variables with global scope, static variables, etc, which of course includes my reference to the RibbonUI). With regards to the ribbon reference I've "solved" the problem by including a "Reset Ribbon" button that restores the reference from a persistently stored pointer and then invalidates the ribbon. Although certainly not the most elegant, this part works just fine.
However, after the introduction of a logging class, the state loss issue haunts me once again. The logger is instantiated in ThisWorkbook's module:
Private Sub Workbook_Open()
Set LogToFile = SingletonFactory.getToFileLogger
End Sub
and is then put to work, for example, as follows:
Private Sub buttonReloadObjects_onAction(ByVal control As IRibbonControl)
LogToFile.trace "Event firing: buttonReloadObjects_onAction"
' more stuff happening...
invalidateRibbon ' restores ribbon object and invalidates it
End Sub
The logger is instantiated when the add-in is loaded so that I have the freedom to log whatever I want within the confines of my add-in's code. It has several logging levels like trace/debug/error/... and a couple of other methods. Usually it works just fine - until the state loss hits (usually caused by an unrelated error, followed by clicking "End").
State loss
At this point the VBA environment forgets about the very existence of my LogToFile object and nothing works any more, because every click on the ribbon controls will trigger a runtime error 91: Object variable or with block variable not set pointing to whatever line is the first to contain a reference to LogToFile.
A solution?
Now, short of doing crazy workarounds like placing
if not isObject(LogToFile) then
Set LogToFile = SingletonFactory.getToFileLogger
end if
LogToFile.trace "Message"
before any occurrence of LogToFile, the only real "solution" I was able to come up with is to wrap all my logger calls in functions (residing in a standard module) and call these functions any time I want to send something to the log. This way I could catch the missing object reference right before the object is needed and I avoid calling methods of uninstantiated objects.
However, after having everything neatly encapsulated in class modules, it strikes me as odd, maybe even wrong(?), going down this route.
So, is there a "proper" solution to the problem of a lost logger instance? Or is my suggested approach already as proper as it can get?
Note: This problem is of course not specific to logging classes. It affects all global variables, most notably my ApplicationEventClass. The issue just happens to be the most glaring with the logger due to its frequent usage around all entry points to the code.
You only need one function that either returns the original variable or resets it. If you call that function LogToFile you don't need to change any of the other code other than removing the Workbook_Open code which is then superfluous. So:
Function LogToFile() As WhateverVariableType
Static temp as WhateverVariableType
If temp is Nothing then Set temp = SingletonFactory.getToFileLogger
Set LogToFile = temp
End Function
This way you will also still benefit from Intellisense when writing the code.
Note: you may not actually need the temp variable - it depends on whether there are settings that you want persisted. If there are, you may want to reset them in the function too.
In Excel when I'm running some code and put a breakpoint in I can look at the values of things in the locals window. In the locals window, when I try to expand a object for the class I've created Excel Crashes with "Microsoft Office Excel has encountered a problem and needs to close. We are sorry for the inconvinience. This also happens if I try to view the object in the watch window.
Any ideas? Or anyone had this before?
Thanks,
Chris
Check, check again and recheck your class properties, especially your GET code. I had the same error where expanding the a custom class object during debugging caused Excel to crash. Excel essentially runs those GET properties when you expand the object in the locals window, so they must compile and not cause any runtime errors.
Of course I can't say this definitely caused the OP's error without seeing their code, but for me the error was an extremely simple one where a GET property contained a type mismatch:
Private pAccFullArr() As String
Public Property Get accFullArr() As Variant
accFullArr = pAccFullArr
End Property
should have been
Private pAccFullArr() As String
Public Property Get accFullArr() As STRING()
accFullArr = pAccFullArr
End Property