Coding in London: December 2006

Sunday 31 December 2006

What I listened to this week #7

Saturday 30 December 2006

Mixing legacy MFC code with Windows Forms (Part 3)

Summary: The ability to intimately mix unmanaged MFC/C++ code with managed code is one of my favorite features in .NET. Migration projects that would otherwise take years can be done in a matter of months. To re-use legacy MFC/C++ code with minimal changes and call the code from a C# Winforms application, you need to:

Create an MFC DLL project and activate the /CLR switch to indicate that this is a mixed assembly.
Add the legacy source files to the MFC DLL project.
Prepare the legacy code so that it compiles for Unicode (see Converting an MFC project to Unicode)
Add a managed class to the above project. This class will be the interface between the managed Winforms application and the legacy MFC/C++ code.

Project settings:

Dynamically link against the MFC DLLs: in Configuration Properties > General > Use of MFC
Compile for Unicode (this is mandatory because .NET works only with Unicode): General > Character Set
Make it a mixed assembly: General > Common Language Runtime Support, set to /CLR. This way the DLL can contain both unmanaged and managed code. The managed code will be visible to any managed application using the DLL.

Can I debug the legacy MFC/C++ code loaded as part of the managed application?

Yes! In the project properties for the managed executable using the DLL, go to the Debug tab and tick Enable unmanaged code debugging.

Step by step:

Create an MFC DLL using the MFC DLL Wizard. Call the project Legacy for instance. Options: Regular DLL using MFC DLL. If the legacy code is an MFC-based MDI application, the main frame will be created as soon as the DLL is loaded (through CLegacyApp::InitInstance)
Add the source files containing the legacy code to this new project.
Set the project settings as described above.
Compile and fix all Unicode issues and other compiler annoyances...
Created a LegacyWrapper C++ class.

Issues associated with compiling with /CLR:

Warning LNK4248: unresolved typeref token (01000013) for '_TREEITEM'; image may not run. Solution here. This is because _TREEITEM is defined in a native library, but the forward declaration is done in an MSIL module. Forcing the definition of _TREEITEM in stdafx.h eliminates the warning.

Cool things in Visual Studio 2005

Useful features that do not exist in Visual Studio 2003

Code definition window (separate window that shows automatically the definition of the variable currently under the cursor)
Find all references command
Class view is searchable
Class view shows base types and derived types (C++)
Class view contains a subpane showing members of current class (makes the tree cleaner)
Find in files dialog is modeless (crucial for refactoring) and automatically moves to display the matched string.

New in Visual Studio 2005: http://msdn2.microsoft.com/en-us/library/88fx1xy0(VS.80).aspx

Wednesday 27 December 2006

IE7 or Firefox?

IE7:

I like the thumbnails view (Ctrl Q)
I like the way it handles RSS feeds: by displaying an HTML view of the feed content first, before offering you to add it to your list.
I don't like the text search.

Firefox:

I like the text search (embedded in the status bar instead of a modal dialog)
I like the download manager.

Sunday 24 December 2006

Books I currently flip through #2

Software Engineering...

Web Services...

Enterprise Databases...

Sound

What I listened to this week #6

Video

Sound

Saturday 23 December 2006

Installing a wireless adapter under Vista RC2

I bought a Netgear WG111T USB2.0 adapter to connect to my Netgear DG834PN router. I thought I would have problems with Vista RC2 but I was surprised how easy it was. I followed the install intructions: installed the drivers first then plugged-in the USB adapter. The drivers installed without any problem. To make things easier, I disabled security on the router and enabled broadcasting of the SSID. I tried starting up the 'NETGEAR WG111T Smart Wizard' but that didn't work: the wizard always closes immediately after launch, so I used the software built into Vista instead. Went into Network and Sharing Center > Manage wireless networks, clicked Add. Then I selected Add a network that is in range of this computer. The wizard displayed my wireless connection with a little icon indicating that it was insecure. I selected the connection then gave a try to Internet Explorer: no problem, Internet worked like a charm. Then I enabled WEP security and disabled the SSID broadcast. Went back to Manage wireless entworks, clicked Add. This time, my wireless connection was displayed as secured this time. I selected it and Vista prompted me for a key. Out of the 4 WEP keys it asked only the first one, which I entered, then it connected successfully. Checked that IE still works OK, no problem.

Sunday 17 December 2006

What I listened to this week #5

Monday 11 December 2006

What I listened to this week #4

Last week

Wednesday 6 December 2006

Handy Collections

Generic key/value pair collection that automatically sorts based on the key: SortedList<TKey,TValue>
Same as above but without the automatic sorting and better performance with large number of items: Dictionary<TKey,TValue>

http://msdn2.microsoft.com/en-us/library/5tbh8a42.aspx

Declare either of them it as follows:

        public SortedList<int, Antenna> antennas;

To iterate through it:

        for each (KeyValuePair<int, Antenna^> kvp in rigging->antennas)

            Antenna^ antenna = kvp.Value;

            CString antennaId;

            antennaId.Format(_T("%d"), kvp.Key);

            (...)

I'm using key/value pair collections because I want to be able to retrieve an element given its key. But it is possible to perform much more complex retrievals in a very elegant way. Anything that implements IEnumerable can be searched.

Monday 4 December 2006

What I listened to this week #3

Vista

SOA

Misc

Last week

Friday 1 December 2006

C# or C++/CLI?

Advantages of C#

no cpp/h, just one file
better IDE support:

better intellisense
code auto-complete
refactoring (auto rename, method extraction, ...)
code snippets
compile errors displayed as you type

no, it's not Microsoft proprietary, there is an ECMA standard for it.

Advantages of C++/CLI

support for mixing managed and unmanaged code. Excellent for re-use of legacy code.
cool language extensions (e.g. for each, ...)
no, it's not Microsoft proprietary, there is an ECMA standard for it

Articles:

C++ Interop is for the Performance Minded Developer

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