Chapter 7 Notes

Title: XAML vs. Code

Summary

• XAML is a better way to write up the "view" part of MVVM.
• XAML is used to write the tree-structured visual user interface

Concepts Not in programs

Converter Classes

Page 134

Below the Color class has a TypeConverter attribute added. Attributes in this context means that the defined attributed class is added to the decorated class. That means that you may have additional properties because of the decoration. You might say that Color now has a TypeConverter object that is instantiated with a Type - in this case the: typeof(ColorTypeConverter)

This, of course, means that Color has additional functionality! We'll learn more about this later!

   1 [TypeConverter (typeof(ColorTypeConverter))]
   2 public struct Color
   3 {
   4     …
   5 }

Property-[Element|Attribute] Syntax:

Page 136

This section spells out how to translate some of the code we are used to writing into XAML. Specifically it identifies how XML elements and attributes map to objects and contents.

• <Frame ...> ... </Frame> is a object element

• <Frame.Content> ... </Frame.Content> is a property element

• In <Frame VerticalOptions="Center" ...> ... </Frame>, VerticalOptions is a property attribute.

XAML Compiler

Page 145

You can force your output to compile the XAML instead of using it directly. This saves time and space, but is new and therefore suspect. Add the following line to your Assembly.cs file in the properties folder.

   1 [assembly: XamlCompilation(XamlCompilationOptions.Compile)]

Programs

Program Baskervilles

Page 41.

Concepts:

1. Shows that text wraps inside a label be default.

2. Shows the use of Device.OnPlatform for padding.

Classes:

1. Label is demonstrated.