Very often when developing managed applications you need to target both VGA (480x640) and the older QVGA (240x320) type of devices. If the AutoScaleMode property of your form is set to Dpi, your controls such as textboxes. labels, buttons etc... will be scaled automatically. However if your draw images yourself or utilizing the ImageList, the images are not going to be autoscaled for you. During the runtime you can easily identify the VGA resolution by using the following code:
public static bool IsHighResolution(this Form form)
{
SizeF currentScreen = form.CurrentAutoScaleDimensions;
if (currentScreen.Height == 192)
{
return true;
}
return false;
}
This is an extension method which is a part of the ControlExtension class from the ListViewDemo project which you can download from here.
So how would you use that method. Here's a sample function that you can place in your form's code:
private void HandleHiRes()
{
if (this.IsHighResolution())
{
this.imageList1.ImageSize = new Size(32 * 2, 32 * 2);
}
}
Enjoy...
I've recently made a substantial update to the MobileMVC framework. I've added the ability to utilize a (D)epenendcy (I)njection container by adding IControllerProvider interface into the framework which looks like this:
public interface IControllerProvider
{
Controller GetController(string name);
Controller GetController(Type type);
Controller GetController<T>();
Controller GetController<T>(IView view);
void RegisterController(Controller controller);
}
This interface gets used in the new class Navigator which could be used instead of NavigationService to navigate between the controllers since it implements the same methods such as Navigate, GoBack, GoForward etc... The Navigator class is exposed as a singleton via the property in the Controller class:
/// <summary>
/// Gets an instance of the Navigator.
/// </summary>
public Navigator Navigator
{
get
{
return Navigator.Current;
}
}
The Navigator class also includes the following static method:
/// <summary>
/// Sets the IControllerProvider to use.
/// </summary>
/// <param name="controllerProvider"></param>
public static void SetControllerProvider(IControllerProvider controllerProvider)
{
if (navigator == null)
{
navigator = new Navigator(controllerProvider);
}
}
As you can see the SetControllerProvider method accepts as a parameter an instance of the IControllerProvider which you will need call when your application is initialized.
Before diving into the full usage sample let's talk about the DI container. As we know, there's not much of the DI and IoC containers exist for .NET CF right now, however Paterns & Practices team has been quetly working on the update of the Mobile Application Blocks that where released a few years back. P&P has recently posted a Community Drop of the code refresh for the Mobility Block on the Codeplex and it includes the new block which is called ContainerModel. P&P has decided to utilize the Funq container that was developed by Daniel Cazzulino. So, I've taken this container and updated the sample for the MobileMVC to make a use of it.
Let's continue on the sample of how you can utilize the new features in the MobileMVC framework. I have modified the existing sample MVCDemoClient (a part of the download of the framework), so let's see how we'd initialize container with the views and controllers:
private static void Initialize()
{
container = new Container();
// Register Login view and controller
container.Register<LoginForm>(c => new LoginForm());
container.Register<LoginController>(c =>
new LoginController(c.Resolve<LoginForm>()))
.InitializedBy((c, v) => v.Container = c);
// Register Search view and controller
container.Register<SearchForm>(c => new SearchForm());
container.Register<SearchController>(c =>
new SearchController(c.Resolve<SearchForm>()))
.InitializedBy((c, v) => v.Container = c);
// Register Search view and controller
container.Register<DetailForm>(c => new DetailForm());
container.Register<DetailController>(c =>
new DetailController(c.Resolve<DetailForm>()))
.InitializedBy((c, v) => v.Container = c);
// Register data model
container.Register<Products>(c => new Products());
// Set ControllerProvider
Navigator.SetControllerProvider(new ControllerProvider(container));
}
In the code above when we register a controller, you can see that we call: .InitializedBy((c, v) => v.Container = c). This means that when an instance of the controller will be created we want to assign the same instance of the container to the Container property which I've added to the controller. We also make a call to the SetControllerProvider method and passing and instance of the ControllerProvider class which as you can guess implements IControllerProvider interface and makes use of the Container:
public class ControllerProvider : IControllerProvider
{
private Container container;
public ControllerProvider(Container container)
{
this.container = container;
}
#region IControllerProvider Members
public Controller GetController<T>()
{
return this.container.Resolve<T>() as Controller;
}
public Controller GetController<T>(IView view)
{
Controller controller = this.container.Resolve<Controller>();
controller.View = view;
return controller;
}
// … Other methods ommitted for brevity
#endregion
}
After this short preparation we can now modifiy our code to use the Navigator class. This is how we can show the SearchForm from the LoginController:
private void ShowSearchView()
{
//SearchController controller = new SearchController(new SearchForm());
//NavigationService.Navigate(controller);
this.Navigator.Navigate<SearchController>();
}
Ability to access the Container from the controller is also giving us much more separation from the Data Model or other services that you may use in the application. For example this is how we can get access to the Products data model in the SearchController:
// ViewLoaded event from the view
private void OnViewLoaded(object sender, EventArgs e)
{
// Show busy cursor
Cursor.Current = Cursors.WaitCursor;
// Get an instance from the container
Products products = this.Container.Resolve<Products>();
// Populate data
products.PopulateList();
// Assign the Model
this.view.ViewData.Model = products;
// Notify the view of the changes
this.NotifyView();
// Restore the cursor
Cursor.Current = Cursors.Default;
}
Overall, I think the usage of the container with the MVC pattern gives you much more flexibility when designing your applications. It allows you to decouple the access to the application services giving you more room during the unit testing as well as making changes to the application without breaking too many dependencies.
You can find the updated version of the MobileMVC framework and the sample in the downloads section of the codeplex project:
http://mobilemvc.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=26507
I've received a question from the customer the other day asking me how he can implement functionality of "dimming" background effect when a message box is shown in his Windows Mobile application. In fact it should be pretty easy to do utilizing the DrawAlpha method from the GraphicsExtender class that I showed you in this webcast. Take a look at the following code snippet:
protected override void OnPaint(PaintEventArgs e)
{
// Create a temp bitmap
Bitmap dimBackGround = new Bitmap(this.Width, this.Height);
Graphics gxTemp = Graphics.FromImage(dimBackGround);
// Color it black
gxTemp.Clear(Color.Black);
// Draw it with alpha transparency
e.Graphics.DrawAlpha(dimBackGround, 100, 0, 0);
// Clean up
gxTemp.Dispose();
dimBackGround.Dispose();
}
The code above shows OnPaint override method in the BackgroundForm class that I've added to the demo project. I've set the FormBorderStyle to None and WindowState to Maximized for this from to make it full screen.
So, now before displaying a message box you will need to show the BackroundForm:
BackgroundForm form = new BackgroundForm();
form.Show();
MessageBox.Show(txtMessage.Text);
form.Close();
And here's the result:
Download the sample code from here.
