Showing tag results for Code

Feb 11, 2013
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Display an overlay on the taskbar button

Raymond Chen
Raymond Chen

Today's "Little Program" displays an overlay on the taskbar button. I've seen some people call this a "badge", but "overlay" is the official term. Start with our scratch program and make the following changes: #include <comip.h> #include <comdef.h> #include <shlobj.h> #include <shellapi.h> _COM_SMARTPTR_TYPEDEF(ITaskb...

Code
Feb 4, 2013
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Obtaining the parsing name (and pidl) for a random shell object

Raymond Chen
Raymond Chen

The parsing name for a shell item is handy, because it lets you regenerate the item later. Actually, the pidl for the shell item is even better, because that is the official way of saving and restoring objects. It's the pidl that gets saved in a shortcut, and since shortcuts can be copied around from machine to machine, pidls must be transportable...

Code
Feb 1, 2013
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Psychic debugging: Why your IContextMenu::InvokeCommand doesn’t get called even though you returned success from IContextMenu::QueryContextMenu

Raymond Chen
Raymond Chen

A customer was having trouble with their IContext­Menu implementation. They observed that their IContext­Menu::Query­Context­Menu method was being called, but when the user selected their menu item, IContext­Menu::Invoke­Command was not being called. Given what you know about shell context menus, you can already direct th...

Code
Jan 31, 2013
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The somewhat misguided question of whether MapViewOfFile or WriteProcessMemory is faster

Raymond Chen
Raymond Chen

A customer asked, "Which is faster for copying data from one process to another; or ?" This is one of those "Huh?"-type questions, where the customer has solved half of a problem and is looking for help with the other half, the half that makes no sense. First of all, the question is malformed because does not copy any data at all. It takes e...

Code
Jan 30, 2013
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Why doesn’t HeapValidate detect corruption in the managed heap?

Raymond Chen
Raymond Chen

A customer had a program that was corrupting the managed heap by p/invoking incorrectly. The problem didn't show up until the next garbage collection pass, at which point the CLR got all freaked-out-like. "According to Knowledge Base article 286470, the tool is supposed to catch heap corruption, but it doesn't catch squat." Depending on your po...

Code
Jan 28, 2013
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Finding a printer, and then creating a shortcut to that printer

Raymond Chen
Raymond Chen

Today's "Little Program" does two things: It looks for a printer in the Printers folder, and then once it finds it, it creates a shortcut to that printer. As is common with "Little Programs", I don't bother with error checking. I'll leave you to do that. Second part first, since it is handy on its own: Creating a shortcut to an arbitrary item ...

Code
Jan 25, 2013
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When you have a SAFEARRAY, you need to know what it is a SAFEARRAY *of*

Raymond Chen
Raymond Chen

A customer had a problem with SAFEARRAY, or more specifically, with CComSafeArray. CComSafeArray<VARIANT> sa; GetAwesomeArray(&sa); LONG lb = sa.GetLowerBound(); LONG ub = sa.GetUpperBound(); for (LONG i = lb; i <= ub; i++) { CComVariant item = sa.GetAt(i); ... use the item ... } The GetAt method returns a VARIANT&, and wh...

Code
Jan 24, 2013
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STRICT_TYPED_ITEMIDS is the shell namespace version of the STRICT macro used by USER and GDI

Raymond Chen
Raymond Chen

Starting with the Windows Vista PlatformSDK, defining the symbol before including shell header files changes declarations that previously had simply used now use one of various types which are more clear about what type of ID list is being used. Think of it as the macro for the shell. The more precise names emphasize the form of the ID lis...

Code
Jan 18, 2013
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What is this rogue version 1.0 of the HTML clipboard format?

Raymond Chen
Raymond Chen

At least as of the time this article was originally written, the HTML clipboard format is officially at version 0.9. A customer observed that sometimes they received HTML clipboard data that marked itself as version 1.0 and wanted to know where they could find documentation on that version. As far as I can tell, there is no official version 1.0...

Code