Category: NETCF

Neither .NETCF v1.0 or v2.0 will support runtime hosting, this means it’s not possible to write a service in managed code which will run within the Services.exe process. However it is often useful to be able to query and manipulate other system services from managed code.

An example of this is where a system service needs to be stopped so that you can access some hardware – such as the OBEX listener service on Windows Mobile which opens the Infrared port. With this scenario in mind I set about wrapping some of the CE functionality for managing services, using the desktop framework as a model.

The resultant library – InTheHand.ServiceProcess.dll is designed as a subset of System.ServiceProcess.dll – this is the assembly which is added as a reference to your project when you create a windows service project with the desktop framework. The library includes a single class ServiceController which is created with the identifier of the service you which to attach to. Under Windows CE these services have an identifier in the form of a device name e.g. AAAN: where AAA is the prefix, often providing a clue as to the purpose of the service, and N is a numerical index. Returning to our example of OBEX the service is called OBX0:. If you don’t know the name of a particular service you can either trawl through the registry under HKLMServices, or better still call the ServiceController.GetServices static method. The final consideration is to ensure you close/dispose the ServiceController when you have finished working with it. Our OBEX shutdown code looks like this:-

ServiceController scObex = new ServiceController(“OBX0:”);
scObex.Stop();

while(scObex.Status!=ServiceControllerStatus.Stopped)
{
    System.Threading.Thread.Sleep(1000);
}

scObex.Close();

Notice that the WaitForStatus method isn’t supported so in this case we periodically check the status while sleeping. If we weren’t bothered when the service shutdown you could leave out this section, even when you call Close() to close our handle to the service it will continue with it’s action and shutdown in it’s  own time.

In terms of platform support, this services.exe model is supported on CE.NET 4.x and above so this includes Windows Mobile 2003 and above.

You can download the library here:-

http://www.inthehand.com/Services.aspx

If you’ve tried documenting .NETCF libraries which make use of Compact Framework specific types you’ll know that you have to do all sorts of workarounds and special builds to get an output which can successfully run through NDoc. This is because although the device specific assemblies such as Microsoft.WindowsCE.Forms are marked retargetable there isn’t an equivalent in the desktop framework to retarget to.

One solution is aggressive conditional compilation to hide all hints of of these device classes. Another way which is cleaner and easier to deal with when you are regularly updating code and documentation is to build your own dummy classes into your NDoc configuration of your project. I’ve done this for documenting my own code as I often find myself using MessageWindows etc in my projects. Ratherthan everyone re-invent the wheel you can use the file (see link below) as-is. You will still be producing a separate dll for documentation purposes but the amount of code you have to hack around with is greatly reduced.

Simply add the attached cs or vb file to your project. Then when you build the project in Debug or Release configuration absolutely nothing is added into your dll which will reference Microsoft.WindowsCE.Forms normally. But when you do an NDoc build and define the NDOC conditional constant it will magically spring into life and create a local dummy copy of the whole Microsoft.WindowsCE.Forms namespace. Because of the way the compiler chooses which class to reference your local version will take preference over the official library, thus removing all dependency on the Microsoft.WindowsCE.Forms library.

Microsoft.WindowsCE.Forms.zip (1.27 KB)

For this to work in VB there are a couple of additional points, firstly make sure you don’t have a Root Namespace configured (Project > Properties). You will also need VBCommenter to build the XML output used to feed Ndoc (Visual Studio 2005 will introduce built in XML comments generation for VB.NET projects).

Of course the same technique can be used for other device specific assemblies such as System.Data.SqlServerCe, although it contains a lot more types and so is less practical to do in this way. You can instead use this technique just with the individual types/methods you use…

A requested feature for NETCF is to retrieve a list of named colors. Fortunately this is easily done using reflection to read all the public statis properties of the Color class:-

System.Reflection.PropertyInfo[] colors = typeof(Color).GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Static);
Color[] allcolors = new Color[colors.Length];


for(int i = 0; i < colors.Length; i++)
{
    allcolors[i] = (Color)colors[i].GetValue(null,null);
}

comboBox1.DataSource = allcolors;

In this example the full list is assigned to a ComboBox for display purposes.

With the release of the Smart Device Framework v1.3 the compiled help documentation was no longer included in the installer. I’ve built a standalone installer to install the full collection of documentation into your Visual Studio help. This release includes:-