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  • QueryInterface fails at casting inside COM-interface implementation

    - by brecht
    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#-form implements has 3 abstract functions. One of these functions is called -by the dll- and i need to implement it myself. In this function i wish to retrieve a property of a form-wide variable that is of a COM-type. The COM library is CANSUPPORTLib The form-wide variable: private CANSUPPORTLib.ICanIOEx devices = new CANSUPPORTLib.CanIO(); This variable is also form-wide and is retrieved via the devices-variable: canreceiver = (CANSUPPORTLib.IDirectCAN2)devices.get_DirectDispatch(receiverLogicalChannel); The function that is called by the dll and implemented in c# public void Message(double dTimeStamp) { Console.WriteLine("!!! message ontvangen !!!" + Environment.NewLine); try { CANSUPPORTLib.can_msg_tag message = new CANSUPPORTLib.can_msg_tag(); message = (CANSUPPORTLib.can_msg_tag) System.Runtime.InteropServices.Marshal.PtrToStructure(canreceiver.RawMessage, message.GetType()); for (int i = 0; i < message.data.Length; i++) { Console.WriteLine("byte " + i + ": " + message.data[i]); } } catch (Exception e) { Console.WriteLine(e.Message); } } The error rises at this line: message = (CANSUPPORTLib.can_msg_tag)System.Runtime.InteropServices.Marshal.PtrToStructure(canreceiver.RawMessage, message.GetType()); Error: Unable to cast COM object of type 'System.__ComObject' to interface type 'CANSUPPORTLib.IDirectCAN2'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{33373EFC-DB42-48C4-A719-3730B7F228B5}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)). Notes: It is possible to have a timer-clock that checks every 100ms for the message i need. The message is then retrieved in the exact same way as i do now. This timer is started when the form starts. The checking is only done when Message(double) has put a variable to true (a message arrived). When the timer-clock is started in the Message function, i have the same error as above Starting another thread when the form starts, is also not possible. Is there someone with experience with COM-interop ? When this timer

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  • Visual Studio Setup and Deployment - D Drive

    - by JB_SO
    I'm creating a VS2005 setup and deployment installer and I need to create some folders in the D: drive since the customer has a partitioned their hard-drive. I've created some folders in the filesystem view and hard-coded the 'DefaultLocation' parameter to point to the D: drive. Now my question is, is it possible to put a 'Condition' parameter that will check to see if the D: drive on the system that the software is being installed is (or is not) a CD-Drive. Thanks

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  • Convert to list after Cast<T>

    - by Timmie Sarjanen
    Hi, I need to convert an IQueryable to List(is it possible to convert to IList?). There had not been an problem if it was not that i need to Cast because I have interfaces to my objects. I've tried most things but for some reason I must run Cast first and then ToList() which generates System.NullReferenceException. How do I solve this? public IQueryable GetPhrases() { return (from r in _repository.All<Phrase>() select r).Cast<IPhrase() }

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  • How to create sockets in google chrome extension ?

    - by Xinus
    Hello, I created small hello world extension for google chrome http://code.google.com/chrome/extensions/getstarted.html. I need to use sockets in extension for peer to peer communication using UDP. Is there any firefox Jslib equivalent in google chrome or how we can use other languages in google chrome extension? I doubt its possible in google chrome, looking at its documentation. ? Are there any other ways to achieve p2p communication in extension? Thanks

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  • Set attributes from dictionary in python

    - by Oscar Reyes
    Is it possible to create an object from a dictionary in python in such a way that each key is an attribute of that object? Something like this: dict = { 'name': 'Oscar', 'lastName': 'Reyes', 'age':32 } e = Employee( dict ) print e.name # Oscar print e.age + 10 # 42 I think it would be pretty much the inverse of this question: Python dictionary from an object's fields

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  • Fastest Strategy for Drawing Flash Particles

    - by user146543
    I am wondering what the fastest approach might be for using Flash/AS3 to render a 2D point plot (sonar lofargram) ; basically screens full of tiny 2D dots using Flash as fast as possible. Any suggestions on where to start? Is Flash capable of displaying 10's of thousands of 2D points (or more) with an acceptable fps?

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  • Downloading & Viewing ePub Books

    - by david
    I have the following requirements for an iPad App and would like to know if it's possible to implement them: Download ePub books and view them in iPads iBooks reader Install the downloaded book in the devices itunes library, so that they are accessibly from the iBooks applications

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  • Jquery Validation Plugin - Require 2 checkboxes

    - by jethomas
    I have a group of 12 checkboxes, all with the same name (name="4_RepPeriods"). I am using the Jquery validation plugin and i want the user to select no more or less than two of these check boxes. If possible I also want the other check boxes to become deactivated (unclickable) after two have been selected. I appreciate the help! Thanks!

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  • What are the most popular RSS readers? (software/web apps)

    - by Daniel Magliola
    I'm creating an application that generates RSS feeds that include an <enclosure (for showing an audio player). Since RSS readers are kinda flaky, in my experience, I'd like to test how my feeds look in as many readers as possible. I only use Google Reader. What other RSS readers (websites or installable apps, for Windows, Linux AND Mac) are popular? Which are the ones I must test on? Thanks! Daniel

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  • Android: how to place a button at an x,y position over top of Canvas

    - by Ben Mc
    Is it possible to place buttons at an X,Y position over the top of a Canvas? For example, on the opening screen of my game, I would like to place buttons for "Play Now", "Instructions", etc, right on top of the canvas. Right now, I'm looking at Touch locations on the Canvas and comparing them to various X,Y bounds. It works, but adding a button with a click listener would probably be much more efficient.

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  • C# 4.0 'dynamic' and foreach statement

    - by ControlFlow
    Not long time before I've discovered, that new dynamic keyword doesn't work well with the C#'s foreach statement: using System; sealed class Foo { public struct FooEnumerator { int value; public bool MoveNext() { return true; } public int Current { get { return value++; } } } public FooEnumerator GetEnumerator() { return new FooEnumerator(); } static void Main() { foreach (int x in new Foo()) { Console.WriteLine(x); if (x >= 100) break; } foreach (int x in (dynamic)new Foo()) { // :) Console.WriteLine(x); if (x >= 100) break; } } } I've expected that iterating over the dynamic variable should work completely as if the type of collection variable is known at compile time. I've discovered that the second loop actually is looked like this when is compiled: foreach (object x in (IEnumerable) /* dynamic cast */ (object) new Foo()) { ... } and every access to the x variable results with the dynamic lookup/cast so C# ignores that I've specify the correct x's type in the foreach statement - that was a bit surprising for me... And also, C# compiler completely ignores that collection from dynamically typed variable may implements IEnumerable<T> interface! The full foreach statement behavior is described in the C# 4.0 specification 8.8.4 The foreach statement article. But... It's perfectly possible to implement the same behavior at runtime! It's possible to add an extra CSharpBinderFlags.ForEachCast flag, correct the emmited code to looks like: foreach (int x in (IEnumerable<int>) /* dynamic cast with the CSharpBinderFlags.ForEachCast flag */ (object) new Foo()) { ... } And add some extra logic to CSharpConvertBinder: Wrap IEnumerable collections and IEnumerator's to IEnumerable<T>/IEnumerator<T>. Wrap collections doesn't implementing Ienumerable<T>/IEnumerator<T> to implement this interfaces. So today foreach statement iterates over dynamic completely different from iterating over statically known collection variable and completely ignores the type information, specified by user. All that results with the different iteration behavior (IEnumarble<T>-implementing collections is being iterated as only IEnumerable-implementing) and more than 150x slowdown when iterating over dynamic. Simple fix will results a much better performance: foreach (int x in (IEnumerable<int>) dynamicVariable) { But why I should write code like this? It's very nicely to see that sometimes C# 4.0 dynamic works completely the same if the type will be known at compile-time, but it's very sadly to see that dynamic works completely different where IT CAN works the same as statically typed code. So my question is: why foreach over dynamic works different from foreach over anything else?

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  • NSThread with class method?

    - by Jeroen Sterckx
    Is it possible to run a class method (starting with a '+') in a separate thread? Normally I call the method like [myClass myController]; I tried [NSThread detachNewThreadSelector:myController toTarget:myClass withObject:nil]; without success.

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