Showing posts with label WPF. Show all posts
Showing posts with label WPF. Show all posts

Wednesday, April 7, 2010

WPF Features NOT in Silverlight Beta 4.0 and other restrictions

1. Simple Inline XAML

2. Silverlight does not support dynamic resources
Only static resources

3. No XPath binding

4. Triggers
workaround
Expression.Samples.Interactivity
System.Windows.Interactivity

Download the example here

5. Silverlight compiled DLL's can only be reference to your Silvelight project.

6. DocumentViewer Control

7. Adorner

8. MultiBindings

9. Updatetrigger

10. Cannot read and write to your local disk
Example:
HtmlPage.Window.Navigate(new Uri("C:\\Users\\userName\\Downloads\\test.pdf"), "_blank");
HtmlPage.Window.Navigate(new Uri("C:\\Users\\userName\\AppData\\LocalLow\\Microsoft\\Silverlight\\is\\t1frcinf.y5b\\adbxgs00.suq\\1\\s\\i4j5zwj5lwo3dexs43ahtvmg2bjlsx11spczjmw5ud3c3dignoaaahea\\f\\MHVStore\\WhatsNewInSilverlight4.pdf"), "_blank");


*** You can access the absolutepath of your IsolatedStorage but it is not the best practice.

10. Refection

Tuesday, April 6, 2010

C# How to open a file

Syntax for opening a file is:

System.Diagnostics.Process.Start("FileNameHere");



However this is not permitted in Silverlight 4.0

Monday, November 23, 2009

Eventing in MVVM pattern without using Caliburn Framework

Steps:

1. You need to have an EventBehaviourFactory class. You can copy this code.


public static class EventBehaviourFactory
{
public static DependencyProperty CreateCommandExecutionEventBehaviour(RoutedEvent routedEvent, string propertyName, Type ownerType)
{
DependencyProperty property = DependencyProperty.RegisterAttached(propertyName, typeof(ICommand), ownerType,
new PropertyMetadata(null,
new ExecuteCommandOnRoutedEventBehaviour(routedEvent).PropertyChangedHandler));

return property;
}

///
/// An internal class to handle listening for an event and executing a command,
/// when a Command is assigned to a particular DependencyProperty
///

private class ExecuteCommandOnRoutedEventBehaviour : ExecuteCommandBehaviour
{
private readonly RoutedEvent _routedEvent;

public ExecuteCommandOnRoutedEventBehaviour(RoutedEvent routedEvent)
{
_routedEvent = routedEvent;
}

///
/// Handles attaching or Detaching Event handlers when a Command is assigned or unassigned
///

///
///
///
protected override void AdjustEventHandlers(DependencyObject sender, object oldValue, object newValue)
{
UIElement element = sender as UIElement;
if (element == null) { return; }

if (oldValue != null)
{
element.RemoveHandler(_routedEvent, new RoutedEventHandler(EventHandler));
}

if (newValue != null)
{
element.AddHandler(_routedEvent, new RoutedEventHandler(EventHandler));
}
}

protected void EventHandler(object sender, RoutedEventArgs e)
{
HandleEvent(sender, e);
}
}

internal abstract class ExecuteCommandBehaviour
{
protected DependencyProperty _property;
protected abstract void AdjustEventHandlers(DependencyObject sender, object oldValue, object newValue);

protected void HandleEvent(object sender, EventArgs e)
{
DependencyObject dp = sender as DependencyObject;
if (dp == null)
{
return;
}

ICommand command = dp.GetValue(_property) as ICommand;

if (command == null)
{
return;
}

if (command.CanExecute(e))
{
command.Execute(e);
}
}

///
/// Listens for a change in the DependencyProperty that we are assigned to, and
/// adjusts the EventHandlers accordingly
///

///
///
public void PropertyChangedHandler(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
// the first time the property changes,
// make a note of which property we are supposed
// to be watching
if (_property == null)
{
_property = e.Property;
}

object oldValue = e.OldValue;
object newValue = e.NewValue;

AdjustEventHandlers(sender, oldValue, newValue);
}
}
}

2. Create a relay command class which inherits ICommand Interface. You can copy this code. An ICommand contains methods to execute commands. A command can be executed many times, and the parameter values can vary. This interface is mandatory on commands.

Namespace: System.Windows.Input
Assembly: PresentationCore (in PresentationCore.dll)

public class RelayCommand:ICommand
{
#region private fields
readonly Action _execute;
readonly Predicate _canExecute;
#endregion private fields

public event EventHandler CanExecuteChanged
{
add
{
if (this._canExecute != null)
CommandManager.RequerySuggested += value;
}
remove
{
if (this._canExecute != null)
CommandManager.RequerySuggested -= value;
}

}

public RelayCommand(Action execute)
: this(execute, null)
{
}

public RelayCommand(Action execute, Predicate canExecute)
{
if (execute == null)
throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
[DebuggerStepThrough]
public bool CanExecute(object parameter)
{
return _canExecute == null ? true : _canExecute(parameter);
}

public void Execute(object parameter)
{
_execute(parameter);
}
}

3. Define a static class to hold a new Attached property that will attach to an object to specify to which command to execute when a particular event is raised. In this example, this is a mouse enter event in the canvas.

public static class CanvasMouseEnterBehaviours
{
public static readonly DependencyProperty MouseEnterCommand = EventBehaviourFactory.CreateCommandExecutionEventBehaviour(
Control.MouseEnterEvent,
"MouseEnterCommand",
typeof(CanvasMouseEnterBehaviours));

public static void SetMouseEnterCommand(Control o, ICommand command)
{
o.SetValue(MouseEnterCommand, command);
}

public static void GetMouseEnterCommand(Control o)
{
o.GetValue(MouseEnterCommand);
}
}

4. Create an ICommand property for Mouse Enter.
public ICommand MouseEnter
{
get
{
if (canvasMouseEnter == null)
canvasMouseEnter = new RelayCommand(param => this.CanvasMouseEnter(param));

return canvasMouseEnter;
}
}

5. Create a public method for your mouse enter event.
public void CanvasMouseEnter(object param)
{
code implementation
}

6. In your XAML, attached the behaviour of your element.






Tuesday, October 27, 2009

How to use DataTemplateSelector in WPF ContentControl

DataTemplateSelector provides a way to choose a data template based on the data object and the data-bound element.

Steps to implement DataTemplateSelector in ContentControl.

1. Create a class that inherits DataTemplateSelector.


2. Implement method SelectTemplate.

public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
code here
}

3. In your XAML under resource, declare all data templates you wish to as example below.



4. Initialize your datatemplate selector class in reference to step number 1.



5. Under ContentControl:
ContentTemplateSelector="{StaticResource xMyTemplateSelector}"/>

Thursday, October 15, 2009

Caliburn: An Application Framework for WPF

Today, I've learned how to use caliburn framework in Model-View-View Model(MVVM) designed pattern.
Without using the application framework, you can set your event in your view.xaml by this:



in your view.cs, you need to hard code this:
void MouseEnter(object sender, MouseEventArgs e)
{
//code here
}

using the implementation above, it breaks the rule of MVVM, the view classes have no idea that the model classes exist, while the ViewModel and model are unaware of the view.

but using caliburn, you need to add this to your view.xaml by



in your viewmodel.cs,
public void OnMouseEnter(MouseEventArgs e)
{
//code here
}

Wednesday, August 26, 2009

Resource Stream in C# .Net

Steps on how to add and retrieve an instance of your resource file:

1. Right click the file, select Properties.

2. Under Build Action, select Embedded Resource as shown below



3. Syntax in retrieving an instance:

FrameworkElement content = new FrameworkElement();
Assembly asm = Assembly.GetExecutingAssembly();
Stream sre = asm.GetManifestResourceStream("namespace here);
content = XamlReader.Load(sre) as FrameworkElement;

Monday, August 24, 2009

XML and LINQ



How to query in C# using LINQ

XDocument xmlFile = XDocument.Load(filename);
var xt = from y in xmlFile.Descendants("Users").Elements("details")
where y.Attribute("userName").Value == x
select new TempClass
{
Name = y.Element("userdetails").Attribute("userFirstName").Value
};


Download Sample Code Here

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