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SmartPhone 2003 and .NETcf Primer
Written by casey chesnut  [author's bio]  [read 45837 times]
Edited by Derek

         

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GAPI

GAPI is still the same, but the difference is that the 2003 emulators for both SP and PPC support it now. You have to deploy gx.dll to the device, and then you can directly pInvoke it and run your app on the emulator. Along with the sample by Alex Feinman, there was an article  that came out while I was playing around with this. My code is real simple and just randomly draws black dots to the screen.

i control the horizontal and the vertical

Web.Services

Of course I also went digging for any changes regarding web services support, and found a nice little surprise! For auto-generated web-service proxies, we now can override GetWebRequest() on the SoapHttpClientProtocol to get access to the actual HttpWebRequest object that will be used to send the SoapRequest. I consider this a big deal! It lets us add Headers, set KeepAlive, and so forth. I'm sure this will make a lot of people happy so that they can add Cookies to keep a session between ASP.NET web service requests ... although I promote using a <Session/> SoapHeader instead because SOAP works on other protocols than HTTP. Prior to this change, you had to either do cookieless web services and munge the URLs, or build the SoapMessages manually and use the HttpWebRequest / Response classes.

a session-enabled web service would look like this:

[WebMethod(true)]
public int GetSessionCount()
{
	int iSess = 0;
	object oSess = Session["count"];
	if(oSess == null)
	{
		iSess = 1;
	}
	else
	{
		iSess = (int) oSess;
		iSess = iSess + 1;
	}
	Session["count"] = iSess;
	return iSess;
}

and you have to add the following overrides to the autogen'd proxy. NOTE I recommend creating a new class, inheriting from the autogen'd proxy, and adding the following code there (so you dont lose changes when updating the web ref). Then call the web service as you normally would using the subclass, and the web service will retain state between calls. NOTE PPC 2003 does not have SP1 in ROM, so this will not work without that addition. Not to mention that the current SP1 does not auto integrate with VS .NET

using System.Net;
private static string sessCookie = null;

protected override WebRequest GetWebRequest(Uri uri)
{
	HttpWebRequest hwr = (HttpWebRequest) base.GetWebRequest (uri);
	if(sessCookie != null)
	{
		hwr.Headers.Add("Cookie", sessCookie);
	}
	return hwr;
}
	
protected override WebResponse GetWebResponse(ebRequest request)
{
	HttpWebResponse hwr = (HttpWebResponse) base.GetWebResponse (request);
	if(hwr.Headers["Set-Cookie"] != null)
	{
		sessCookie = hwr.Headers["Set-Cookie"];
		//"ASP.NET_SessionId=g3exyaihxpmbkr55rhfxwq45; path=/"
	}
	return hwr;
}

Now for the bad news. Although WSE (Web Service Enhancements) 2.0 is now a technical preview and Soap 1.2 is now a recommendation, we still have no word on getting a client-side version of the WSE for mobile clients to support WS-Security, DIME, WS-Routing, WS-Policy etc... not to mention WS-Reliablity which should ultimately find its way into the WSE and would make perfect sense for devices that can constantly lose their connection. My only hope is the new Messaging model introduced in WSE 2.0, which begins to decouple the WSE from ASP .NET. With this break, it seems like the best chance we have for ultimately getting the WSE for the .NETcf. My guess is that the decoupling of WSE from ASP .NET will kill off the SoapFormatter in System.Remoting as well? I'm holding my breath to find out what 'Indigo' is ...

Security

I dont have an actual phone, so I do not entirely understand this ... but it is something to be aware of. SmartPhones follow the CE module security scheme. The device can be either a One-Tier or Two-Tier devices. One-Tier devices treat access to all parts of the device as needing the same security, while Two-Tier might provide access to some functions, but restrict others. A privileged certificate would be required to access those restricted Two-Tier functions, and can be obtained through programs such as MS Mobile2Market. As well as being 1 or 2-Tier, the devices can be in different modes: Open, Locked, Prompt. The apps ability to run will then depend based on 3 things:

• whether it is a 1 or 2-Tier device
• what mode it is in: Open, Locked, Prompt
• if the app is signed with a privileged certificate, unprivileged certificate, or not at all

The emulator is 1-Tier and Open by default ... meaning you dont have to worry about this when using it. NOTE this security model is different than Code Access Security with the full framework, which does not exist for the .NETcf. Also related to Security, the CryptoApi does exist on the SmartPhone and can be pInvoked. NOTE The high encryption pack rsaenh.dll exists on the emulator, but coredll.dll is what should be pInvoked. Did not see rsabase.dll at all.

SqlCe

SqlCe does not exist for the SmartPhone. So I asked on the MS smartphone.developer newsgroup what should be used instead. Peter Foot felt it should be replaced with the built-in XML support (e.g. DataSets and / or WebServices) and / or the CSV lib from opennetcf.org. Another option might be pInvoking the low level CE DB data store. Some combination of the above seems like it will work for a lot of apps. 

APIs

There are some interesting APIs that can be pInvoked as well. The ones I took note of included Bluetooth, Vibrate, Connection Manager, and Speech Recognition. The documentation even explicitly points out 3 that also exist on PocketPC Phone Edition (TAPI, SMS, and SIM).

Questions

These are just random thoughts that popped into my head and I did not have time to look into.

• With Speech .NET Beta 3, we get a Pocket IE add-in for Speech, will the SmartPhone PIE get the same add-in for SALT'ed web sites?
• From a newsgroup posting, a person asked about getting DirectPlay for SP. The last drop was DirectPlay for PPC 2002. This is relevant to me, because I wrote an article on how to pInvoke DirectPlay for PPC from a combination of managed and unmanaged code.
• When do we get Flash for SmartPhones?
• e911 - forget privacy, I want Location Based Services
• MMS, SyncML, SVG?

Conclusion

The SmartPhone 2003 SDK allows for managed coders to begin developing apps for the SmartPhone. It will be an easy transition for those already familiar with the .NETcf and developing for the PocketPC or CE. Cannot wait for the actual SP 2003 hardware to become readily available to consumers. Later.

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