21 JULY 2019

We saw how to add Resources into our WPF application. the Resources define styling attribute (such as color) into a specific key. this allows us to attach a definition (such as color) into our controllers. what do we gain from all of this? answer: if we choose to modify the color of many controllers at once- we can achieve that but simply modify the Resource only one time! the Resources could be declared at a Local scope, Window scope, Application scope or as a Dynamic resource (in order to modify the value from the C# code). we saw how to define a Style. a Style is a set of design properties which are used to define an appearance of a component. we can use these properties in order to define the appearance of our controllers (like Resource) and update them at once. we can also use Style in order to Trigger a UI modification. we do that by defining two styles into a controller: one Style for the “regular mode” and a second Style for a triggered event. whenever the event occurs- the new Style will take place. for example – mouse over. we learned about DataBinding types: one way, one time and two ways. the one way is used to update a target control whenever the source control is modified (for example a slider bar could be used as a source and a text block could be used as the target. whenever the user “drags” the slide bar – the value of the text block will be updated according to the slide bar position [in percentage]). one way means that the text block will be updated only once- from the slide bar value. two ways means for example, that if a slider is attached to a text box, then whenever the user “drags” the slide bar- the text box text will be updated. and whenever the user modified the text in text box- the slider will be updated. we learned about DataContext. whenever you Bind a property into the XAML you need to specify a DataContext so the WPF will know which object holds the specified property. the DataContext could be set in a controller level, in a panel level or in a window level

More topics covered:

• UpdateSourceTrigger – change, focus lost
• DataTrigger for Style (data modification event)
• DataContext set to an Object (i.e. Person)
• App.xaml Application.Resources
• Style Trigger could modify text
• Style Trigger could be fired on check box selection

Links:

• Class code: Home work solution – 1
• Class code: Home work solution – 2
• Class code: Resources
• Class code: Style
• Class code: Trigger
• Class code: Data binding
• Class code: Data Context
• DataContext – nice article
• Binding Modes (i.e. one-way, two-way…)
• Home Work!
• Lesson Summary Video!