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What are the types for data binding modes in WPF?
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1.One-way binding:
The data flows from the source to the target,each time a change is made on the source
2.One-time binding:
Sends data from source to the target, however it does this only when the application is started or when the datacontext changes
3.One-way-to-source binding:
sends data from the target to source
4.Two-way binding:(Default)
Sends the source to the target and if there are changes in the target, those values will be sent back to the source.
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What are the panels in WPF?
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1.CANVAS - Explicitly positioning of controls
2.DOCKPANEL - Similar to windows form docking application
3.GRID - Can arrange child controls with rows and columns
4.STACKPANEL - Used to organize child controls either horizontally or vertically
5.WRAPPANEL - Can arrange child controls from left to right one after the other as long as they fit in to next line
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What are the Resources, Styles and Triggers?
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Style - element containing setter elements.
Triggers - used to change the look and feel of the controls dynamically.
Resources - Styles and Triggers are stored in the resources
Static Resources - resources are searched at load time
Dynamic Resources - If the resource changes while the program is running
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What is CLR Property?
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CLR properties are really just safe wrappers around a Private member variable, such that the correct access modifiers can be applied to the property, so we could have a Read or a Read/Write or just a Write property. But basically that's it. This is all CLR properties really do for us.
they are defined like this
private int x;
public int X
{
get { return x; }
set { x = value; }
}
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What is dependency property in WPF?
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WPF elements are classes with methods, properties and events. Nearly every property of a WPF element is a dependency property. Dependency properties are used with databinding, animation, resources and styles.
Only a class that derive from base class DependencyObject can include dependency properties. For Example
public class MyDependencyObject : DependencyObject
{
public static readonly DependencyProperty SomeStateProperty = DependencyProperty.Register("SomeState", typeof(String), typeof(MyDependencyObject));
public string SomeState
{
get {return (string)this.GetValue(SomeStateProperty);}
set { this.SetValue(SomeStateProperty, value); }
}
}
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What is attached property in WPF?
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A WPF element can also get features from the parent element. For example, if the button element is located inside a Canvas element. the button has Top and Left properties that are prefixed with the parent element's name. Such a property is known as attached property.
<Canvas>
<Button Canvas.Top="35" Canvas.Left="45">
Click Me!
</Button>
</Canvas> |
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What is Property Invalidation?
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Its used to update the custom control whenever the property changes.Adding property invalidation callbacks to a custom control is as easy as adding a PropertyChangedCallback object to a PropertyMetadata object and add this PropertyMetadata object to Register() or RegisterAttached() methods.
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What are templates?
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A template is similar to a style, and two different kinds are available:
Data templates: allow using XAML's DataTemplate element to specify a group of characteristics for how data should be displayed. Colors, alignment, and more can be defined once in a data template, then used elsewhere in an application's user interface.
Control templates: allow using XAML's ControlTemplate element to define the appearance of a control.
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What is Resource Dictionary?
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The content of the file is just a ResourceDictionary - and because the ResourceDictionary is the root element in the Xml file we need to define the default namespaces, which you would probably be more used to seeing on a new root-level Window or Page when you create a new Xaml file in Visual Studio. The contents of the resource dictionary is a perfectly normal WPF style.
The second step is to merge this resource stored in an external file into one of the resource dictionaries in our application. For this example we'll merge it in to the Application.Resouces collection (located in the App.xaml file). This is done by adding the elements highlighted below which point to the TextStyle.xaml file we created.
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what is ObservableCollection?
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Represents a dynamic data collection that provides notifications when items get added, removed or when the whole list is refreshed.
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