What are the most valuable .Net Compact Framework Tips, Tricks, and Gotcha-Avoiders? [closed]

Answer 1

When doing anything with OutlookSession, always

• instantiate it on the main (application) thread
• execute against it on the main thread (I use a Control object to Invoke against)
• and dispose of it within a decent timeframe (if you don't you'll have strange behavior in Pocket Outlook)

Answer 2

Working with Compact Framework and SqlCe, there can be a lot of issues with performance, memory leaks and thread synchronisations.

Rules to abide by to minimise Compact Framework - SqlCe headaches.

1. Use one SqlCe connection - you can use a locking mechanism on the connection to enable the use of one connection on multiple threads.
2. Bulk Data inserts are slow because of the Sqlce Engine. Use direct table inserts, which has a similar performance benefit to writing directly to a text file.
3. Dispose the SqlCe connection on close of the application. This makes sure all resources are cleaned up.
4. Dispose all commands, datareaders etc after every call to the database. Using statements are your friend. Make sure reader objects are inside command using statements etc...

Answer 3

• You will encounter a lot of Bugs and Limitations in .net cf. You will have to monkey patch them. its ugly but you will have no choice.

• You will end up writing a lot of custom controls. As most of the controls in the framework don't support features that are commonly requested by clients. So its a good practice to create custom controls for each and every control you use from the start. Even though you might not have anything in them when you begin. You can add custom logic later on. Without having to modify a lot of existing code.

• If you need validation you could use .net validation framework

• Its a good idea to sperate your code everywhere in your App. You could use the MVC pattern. And if you choose to use it you can get a head start by using MobileMVC
• If you need a rich UI tool kit you can look at Resco (google it).
• VS Designer will be your arch enemy.

This is all that i can think of right now.

Answer 4

Most out of the ordinary stuff requires direct call the Windows API through P/Invoke. I have found http://www.pinvoke.net/ to be a great resource for P/Invoke on both Win32 and Windows CE.

Answer 5

This isn't specific to just Compact Framework devices, however it rears it's ugly head a lot more when developing on them due to resource contraints developing on a mobile platform.

---

Recently I came across a great post as part of a thread on managing memory leaks which helped me identify a leak I didn't know about in a bug when setting the DataGrid.DataSource in one of our mobile apps.

When binding a DataGrid, you should not directly use something like:

dgDataGrid.DataSource = dsDataSet;

As this creates a new CurrencyManager each time that doesn't properly get disposed of. Instead you want to bind the DataGrid to a BindingSource first in order to avoid the resource leak.

bsData.DataSource = dsDataSet;

dgDataGrid.DataSource = bsData;

Who knew? Scott Langham did in another post. Thanks Scott!

Answer 6

If you have to support multiple screen sizes/resolutions, form inheritance is an excellent way to do it. Basically you design your form to fit the standard 320x240 screen. To support a different screen size, you just add a new form, inherit from your custom form (instead of just Form), and then re-arrange the controls as necessary.

Another useful trick is to wrap the ShowDialog call in a way that lets you set the parent form's caption to "" temporarily - this keeps all the open forms in your application from showing up in the running programs list. Another way to enhance the wrapper is to PInvoke SetForegroundWindow with the handle of the parent window. This ensures that the parent will always re-appear after the child is closed; without this call, it's possible for other windows to be inserted in the z-stack above the parent form.

Watch out for encryption on the SD card. SqlCE will stop working altogether. Oracle Lite's behavior under encryption is much more sinister, since parts of it work and parts of it don't.

Avoid SqlCE RDA and merge replication. These would be fantastic tools if they worked reliably, but they don't in situations where the network connection can unexpectedly be dropped during replication (quite common in the WM world). This one bit me HARD with a production app. The MS support tech we dealt with was finally forced to acknowledge that it just doesn't work 100%. Actual quote: "just keep trying to replicate - they'll merge correctly eventually".