queryinterface

QueryInterface for interface VBA._Collection failed

Hi, we are randomly seeing this error during long executions of our system. The error is caught by our alarm system, and we successfully retry, and continue running the system. The only hits we found on Google seem to mention corrupt installations. We do not think this is the case here, since our systems is running, gets the error, and c...

Zero results in Query/GqlQuery

How do I know if the results of my query either using the Query interface or the GqlQuery interface returned zero results? Would using .get() on zero results produce an error? If yes, what's the best way to handle it? ...

QueryInterface method for the IID_IPersistStreamInit quit working

I have an application that I've been using to parse data from an HTML document. The application has been working for a few years until this week when the QueryInterface method for the IID_IPersistStreamInit started failing. The call to QueryInterface is returning -2147467262 which fails the SUCCEEDED(hr) test. Any ideas why this quit wor...

Can't access the COM interface

Hi all. I am working with the scantest of application documentation (shocker), and what there is seems to be misleading/contradicting. I will ask the software company as well, but their last reply took weeks. In the meantime....(thanks)..... I am trying to access the [alledged] COM interface of a GUI application we'll call: Xyz My Ques...

QueryInterface fails at casting inside COM-interface implementation

I am creating a tool in c# to retrieve messages of a CAN-network (network in a car) using an Dll written in C/C++. This dll is usable as a COM-interface. My c#-formclass implements one of these COM-interfaces. And other variables are instantiated using these COM-interfaces (everything works perfect). The problem: The interface my C#-fo...

Access violation exception from Delphi's Supports -> QueryInterface

Hi, I have the following piece of code: for i := 0 to FControlList.Count - 1 do if Supports(IMyControl(FControlList[i]), IMyControlEx) then begin MyControlEx := IMyControl(FControlList[i]) as IMyControlEx; MyControlEx.DoYourMagic(Self, SomeData); end; This code is called many times during my applic...

Access violation after GetInterface/QueryInterface in Delphi

Hi everyone! First, I'm very new in Delphi and COM, but I should build COM application in Delphi. I read a lot of articles and notes on the internets, but COM and COM in Delphi are still not clear to me. My sources - http://www.everfall.com/paste/id.php?wisdn8hyhzkt (about 80 lines). I try to make a COM Interface and Impl class - it w...

Delphi: How to implement QueryInterface of IUnknown?

In Delphi, IUnknown is declared as: function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall; Note: The output parameter is untyped In my TInterfacedObject descendant i need to handle QueryInterface, so i can return an object that supports the requested interface: function TFoo.QueryInterface(const IID: TGUID; out Obj): ...

InvalidCastException, QueryInterface call failing on COM component

First off, I'm extremely new to the whole COM scene so bare with me. I'm trying to use PCAnywhere's Ole automation in a .net applicaction I'm currently developing (VS 2010, c#). PCA 12.5 comes with a couple tlb files that when I try to add as references through VS I get an error on both saying 'A reference to 'E:\Dev\PcaOle\awrem32.tlb'...

Has anyone else noticed this behaviour in Delphi using QueryInterface?

Here are my types... unit unitTestInterfaces; interface type IFoo = interface ['{169AF568-4568-429A-A8F6-C69F4BBCC6F0}'] function TestFoo1:string; function TestFoo:string; end; IBah = interface ['{C03E4E20-2D13-45E5-BBC6-9FDE12116F95}'] function TestBah:string; function TestBah1:string; end; TFooBah ...

How to make 'will_paginate' lazyload in rails 3?

In rails3, almost all query interface change to be lazyloading now, but 'will_paginate' will hit the database imediately after you use the 'paginate' method. How can I make it lazyload records? ...

What is IconnectionPoint and EventHandling

Trying to understand What is IConnectionPoint and how this is connected to IConnectionPointContainer,IEnumConnectionPoints,IEnumConnections and EventHandling. Read the artcicles from MSDN and CodeProject which is explaining a about other methods like: QueryInterface() and otherthings. I am unable to figure out how all these things(ICo...

How can I do a Custom QueryInterface for .NET 3.5?

I have .NET Assembly exposed to COM, and I want to create a custom QueryInterface, otherwise my Class will have to implement a lot of interfaces. Currently my implementation is like this [ComVisible(true] [ProgId("SomeLib.SomeClass")] [Guid("516E4529-38F1-44EE-B340-ABFA498DC922")] public class MyClass : Interface1, Interface2......, et...

Python, ArcObjects, and .AppRef: how to get from IAppROT to IMxDocument?

I am writing an external Python/comtypes script (in PythonWin) that needs to get a reference to the current ArcGIS 10.0 ArcMap session (through the ArcObjects COM). Because the script is outside the application boundary, I am getting the application reference through the AppROT (running object table). The first code snippet below is the...