XAML Essentials: Everything You Need to Know about XAML

XAML Developer Reference PDF 15

XAML (eXtensible Application Markup Language) is a declarative markup language that is used to define user interfaces (UI) for various Microsoft technologies, such as Windows Presentation Foundation (WPF), Silverlight, Windows 8, Universal Windows Platform (UWP), etc. It allows developers and designers to create rich, interactive, and data-driven UIs with ease and flexibility.

Xaml Developer Reference Pdf 15

Download

In this article, we will explore what XAML is, how it works, and how to use it for UI design and development. We will also cover some of the advanced topics, such as creating and using custom XAML files, optimizing XAML performance and compatibility, and following the best practices and tips for XAML development. By the end of this article, you will have a solid understanding of XAML and its applications.

What is XAML and why is it important?

XAML stands for eXtensible Application Markup Language. It is a XML-based language that allows developers and designers to describe the UI elements, their properties, events, data bindings, resources, styles, animations, etc. in a declarative way. Unlike procedural code, which specifies how to create the UI elements, XAML specifies what the UI elements are.

XAML has many advantages over procedural code for UI design and development. Some of them are:

XAML separates the UI logic from the business logic, making the code more readable, maintainable, and testable.

XAML enables collaboration between developers and designers, as they can work on different aspects of the UI without interfering with each other.

XAML supports design-time tools, such as Visual Studio and Expression Blend, that provide graphical editors, drag-and-drop features, property panels, etc. to create and modify the UI visually.

XAML supports data binding, which is a mechanism that connects the UI elements to data sources, such as objects, collections, XML files, databases, etc. Data binding enables automatic synchronization between the UI and the data without writing any code.

XAML supports templates, which are reusable chunks of XAML that define the appearance and behavior of UI elements. Templates allow developers and designers to customize the UI elements without affecting their functionality.

XAML supports styles and resources, which are collections of property values that can be applied to multiple UI elements. Styles and resources enable consistent look-and-feel across the UI and reduce code duplication.

XAML syntax and features

XAML syntax is based on XML syntax, which means that it follows some basic rules:

XAML documents consist of elements that are enclosed in angle brackets ().

Elements can have attributes that specify their properties or events.

Elements can have child elements that form a hierarchical structure.

Elements can have content that is either text or other elements.

Elements must have a closing tag or be self-closing.

Here is an example of a simple XAML document that defines a window with a button:

In this example, the Window element is the root element of the document. It has two attributes: x:Class, which specifies the name of the code-behind class that contains the logic for the window, and xmlns, which specifies the default namespace for the elements in the document. The xmlns attribute also has a prefix (x), which indicates that it belongs to a different namespace than the default one. The Button element is a child element of the Window element. It has two attributes: Content, which specifies the text that appears on the button, and Click, which specifies the event handler that is invoked when the button is clicked.

XAML has some features that make it more expressive and powerful than XML. Some of them are:

XAML supports property element syntax, which allows setting complex properties or collections as child elements instead of attributes. For example:

XAML supports markup extensions, which are expressions that are enclosed in curly braces ( ). Markup extensions provide a way to dynamically assign values to properties or events from various sources, such as resources, bindings, converters, etc. For example:

XAML supports type converters, which are classes that convert values from one type to another. Type converters enable implicit conversion of attribute values to the expected property types. For example:

In this example, the Width and Height attributes are converted from string to double, and the Fill attribute is converted from string to Brush.

XAML development tools and resources

There are many tools and resources available for XAML development. Some of them are:

Microsoft Visual Studio: The most popular integrated development environment (IDE) for XAML development. It provides a powerful code editor, a graphical designer, a debugger, a profiler, a testing framework, and many other features.

Microsoft Expression Blend: A design tool that complements Visual Studio for creating rich and interactive UIs with XAML. It provides a visual editor, a storyboard editor, a sample data generator, a behavior library, and many other features.

XAML Developer Reference PDF 15: A comprehensive guide to XAML development that covers all the topics in this article and more. It is available for download at https://riptutorial.com/Download/xaml.pdf.

XAML namespaces: The official documentation for the XAML namespaces that define the classes, structures, interfaces, methods, properties, and events that make up the XAML framework. It is available at https://docs.microsoft.com/en-us/dotnet/api/?view=net-5.0&term=xaml.

XAML tutorials: A collection of tutorials that teach various aspects of XAML development with examples and exercises. It is available at https://riptutorial.com/xaml.

How to use XAML for UI design and development

Now that we have learned what XAML is and why it is important, let's see how to use it for UI design and development. In this section, we will cover some of the most common and useful topics in XAML development, such as layout controls and panels, data binding and templates, styles and resources.

XAML layout controls and panels

XAML layout controls and panels are elements that provide different ways to arrange and position other UI elements within a container. They are essential for creating responsive and adaptive UIs that can adjust to different screen sizes and orientations.

There are many types of layout controls and panels in XAML. Some of them are:

<Canvas> A panel that allows absolute positioning of UI elements by using coordinates. It is useful for creating custom shapes and animations. For example: <Canvas Width="200" Height="200" Background="LightGray"> <Ellipse Canvas.Left="50" Canvas.Top="50" Width="100" Height="100" Fill="Blue" /> <Rectangle Canvas.Left="25" Canvas.Top="25" Width="50" Height="50" Fill="Red" /> <TextBlock Canvas.Left="75" Canvas.Top="75" Text="Hello" /> </Canvas> <DockPanel> A panel that arranges UI elements along the edges of the container. It is useful for creating toolbars and menus. For example: <DockPanel LastChildFill="True"> <Menu DockPanel.Dock="Top"> <MenuItem Header="File"> <MenuItem Header="New" /> <MenuItem Header="Open" /> <MenuItem Header="Save" /> </MenuItem> <MenuItem Header="Edit"> <MenuItem Header="Cut" /> <MenuItem Header="Copy" /> <MenuItem Header="Paste" /> </MenuItem> </Menu> <StatusBar DockPanel.Dock="Bottom"> <TextBlock Text="Ready" /> </StatusBar> <TextBlock TextWrapping="Wrap"> This is the main content of the dock panel. </TextBlock> </DockPanel> <StackPanel> A panel that arranges UI elements in a single line, either horizontally or vertically. It is useful for creating lists and forms. For example: <StackPanel Orientation="Vertical"> <TextBlock Text="Name:" /> <TextBox /> <TextBlock Text="Email:" /> <TextBox /> <Button Content="Submit" /> </StackPanel> <Grid> A panel that arranges UI elements in rows and columns. It is useful for creating complex and flexible layouts. For example: <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="" /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="" /> <ColumnDefinition Width="2*" /> </Grid.ColumnDefinitions> <TextBlock Grid.Row="0" Grid.ColumnSpan="2" Text="Title" HorizontalAlignment="Center" FontSize="24" /> <Image Grid.Row="1" Grid.Column="0" Source="image.png" Stretch="UniformToFill" /> <TextBlock Grid.Row="1" Grid.Column="1" TextWrapping="Wrap"> This is some text that goes next to the image. </TextBlock> <Button Grid.Row="2" Grid.ColumnSpan="2" Content="OK" HorizontalAlignment="Right"/> </Grid> <WrapPanel> A panel that arranges UI elements in multiple lines, either horizontally or vertically, and wraps them to the next line when there is no more space. It is useful for creating flow layouts and galleries. For example: <WrapPanel Orientation="Horizontal"> <Image Source="image1.png" Width="100" Height= "100"/> <Image Source= "image2.png "Width= "100 "Height= "100 "/> <Image Source= "image3.png "Width= "100 "Height= "100 "/> ... </WrapPanel> <UniformGrid&gt: A panel that arranges UI elements in rows and columns of equal size. It is useful for creating grids and matrices. For example: <UniformGrid Rows="3" Columns="3"> <Button Content="1" /> <Button Content="2" /> <Button Content="3" /> <Button Content="4" /> <Button Content="5" /> <Button Content="6" /> <Button Content="7" /> <Button Content="8" /> <Button Content="9" /> </UniformGrid> <RelativePanel&gt: A panel that arranges UI elements relative to each other or to the panel. It is useful for creating adaptive layouts that can respond to different screen sizes and orientations. For example: <RelativePanel> <TextBlock x:Name="TitleTextBlock" Text="Title" FontSize="24" RelativePanel.AlignHorizontalCenterWithPanel="True" /> <Image x:Name="LogoImage" Source="logo.png" Width="100" Height="100" RelativePanel.Below="TitleTextBlock" RelativePanel.AlignLeftWithPanel="True" /> <TextBlock x:Name="DescriptionTextBlock" TextWrapping="Wrap" Text="This is some text that goes next to the logo." RelativePanel.Below="TitleTextBlock" RelativePanel.RightOf="LogoImage" /> <Button x:Name="OKButton" Content="OK" RelativePanel.AlignBottomWithPanel="True" RelativePanel.AlignRightWithPanel="True"/> </RelativePanel> XAML data binding and templates

XAML data binding is a mechanism that connects the UI elements to data sources, such as objects, collections, XML files, databases, etc. Data binding enables automatic synchronization between the UI and the data without writing any code.

XAML data binding has three main components:

The binding source: The data source that provides the data to be displayed or edited.

The binding target: The UI element that displays or edits the data.

The binding object: The object that connects the binding source and the binding target and defines how the data is transferred and formatted.

Here is an example of a simple XAML data binding that binds a text block to a string property:

In this example, the Window element has a DataContext property that sets the binding source to an instance of a Person class that has a Name property. The TextBlock element has a Text property that sets the binding target to the text that appears on the screen. The Binding object is created implicitly by using the markup extension syntax ( ). It specifies the Name property as the path of the binding source.

XAML data binding supports various features and options, such as:

Binding modes: The direction of data flow between the source and the target. There are four modes: OneWay (default), TwoWay, OneWayToSource, and OneTime.

Binding converters: The classes that convert values from one type to another during data transfer. They implement the IValueConverter interface and provide two methods: Convert and ConvertBack.

Binding validation: The mechanism that checks whether the data entered by the user is valid and provides feedback. It uses the IDataErrorInfo or INotifyDataErrorInfo interfaces or the ValidationRules collection.

Binding updates: The triggers that determine when the data transfer occurs. They can be set by using the UpdateSourceTrigger property. There are four triggers: PropertyChanged (default for some properties), LostFocus (default for some properties), Explicit, and Default.

XAML templates are reusable chunks of XAML that define the appearance and behavior of UI elements. Templates allow developers and designers to customize the UI elements without affecting their functionality.

There are two types of templates in XAML:

Data templates: The templates that define how data objects are displayed in UI elements, such as list boxes, combo boxes, etc. They are set by using the DataTemplate element and the ItemTemplate property.

Control templates: The templates that define how controls are rendered in UI elements, such as buttons, text boxes, etc. They are set by using the ControlTemplate element and the Template property.

Here is an example of a simple XAML data template that displays a person's name and age in a list box:

In this example, the Window element has a Resources property that defines a DataTemplate element with a key of PersonTemplate. The DataTemplate element contains a StackPanel element that arranges four TextBlock elements horizontally. The TextBlock elements bind to the Name and Age properties of the data objects. The ListBox element has an ItemsSource property that binds to a collection of Person objects and an ItemTemplate property that references the PersonTemplate resource.

Here is an example of a simple XAML control template that changes the appearance of a button:

XAML styles and resources

XAML styles and resources are collections of property values that can be applied to multiple UI elements. Styles and resources enable consistent look-and-feel across the UI and reduce code duplication.

XAML styles are defined by using the Style element and the Style property. A style can have a key that identifies it and a target type that specifies the type of UI elements that can use it. A style can also have a set of setters that define the property values for the UI elements. A style can also inherit from another style by using the BasedOn property.

Here is an example of a simple XAML style that sets the font size and color of text blocks:

In this example, the Window element has a Resources property that defines a Style element with a key of TextStyle and a target type of TextBlock. The Style element has two Setter elements that set the FontSize and Foreground properties to 18 and Green, respectively. The StackPanel element contains two TextBlock elements that have a Style property that references the TextStyle resource.

XAML resources are defined by using any XAML element that can be used as a value for a property, such as brushes, colors, fonts, images, etc. A resource can have a key that identifies it and can be referenced by using the StaticResource or DynamicResource markup extensions. A resource can also be defined in different scopes, such as application, window, page, user control, etc.

Here is an example of a simple XAML resource that defines a brush and uses it for the background of a button:

<Window x:C

Jose Alberto Fuentes Group