Benutzer:MovGP0/WPF/Data Binding

WPF Data Binding

DataContext	defines the source data object (ie. a ViewModel)
Binding	binding to a property of the source data object
Change Notifications	events that keep UI and model in sync

Data Sources

Entity Data Sources
Change Notifications
EditableObjects and CollectionViews
DataSet and XML data sources

Binding Properties

Bindings can target

Any FrameworkElement
Any DependencyProperty

Property	Usage
Path	Source property
XPath	XML source node
Source	Source object
Mode	OneTime, OneWay, OneWayToSource, TwoWay

<TextBox Text="{Binding Path=Property}" />

Binding to Control

private static readonly DependencyProperty NumeratorProperty = 
    DependencyProperty.Register(nameof(Numerator), typeof(object), typeof(Fraction), new PropertyMetadata(null));

public object Numerator
{
    get { return (object)GetValue(NumeratorProperty); }
    set { SetValue(NumeratorProperty, value); }
}

public Fraction()
{
    InitializeComponent();
    DataContext = this;
}

<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:t="clr-namespace:System.Threading;assembly=mscorlib"
      DataSource={Binding}>
  <StackPanel>
  <TextBlock Text="{Binding Path=Numerator}" />
  <Border Height="1" Margin="2" Background="Black" />
  <TextBlock Text="{Binding Path=Denominator}" />
  </StackPanel>
</Grid>

Binding to an static .NET object

<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:t="clr-namespace:System.Threading;assembly=mscorlib">
  <TextBlock Text="{Binding Path=CurrentCulture, Source={x:Static t:Thread.CurrentThread}}" />
</Grid>

Binding to an resource

<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:s="clr-namespace:System;assembly=mscorlib">
  <Grid.Resources>
    <s:String x:Key="myValue">Hello World!</s:String>
  </Grid.Resources>
  <StackPanel>
    <TextBlock Text="{Binding Source={StaticResource myValue}}" />
    <TextBlock Text="{Binding Path=Length, Source={StaticResource myValue}}" />
  </StackPanel>
</Grid>

Binding to an DataContext

<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:s="clr-namespace:System;assembly=mscorlib"
      DataContext="{x:Static s:Environment.OSVersion}">
  <StackPanel>
    <TextBlock Text="{Binding Platform}" />
    <TextBlock Text="{Binding Version}" />
    <TextBlock Text="{Binding ServicePack}" />
  </StackPanel>
</Grid>

Binding to an ViewModel

<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:s="clr-namespace:System;assembly=mscorlib"
      DataContext="{ViewModel}">
  <StackPanel>
    <TextBox Text="{Binding FirstName}" /> <!-- updates ViewModel on LostFocus event -->
    <TextBox Text="{Binding LastName, UpdateSourcheTrigger=PropertyChanged}" /> <!-- updates ViewModel on every property change -->
  </StackPanel>
</Grid>

To update the UI when a property of the ViewModel changes, implement the INotifyPropertyChanged interface on the ViewModel.

Data Template

Single Item

// in constructor 
InitializeComponent();
var person = new Person { ... }; 
DataContext = person;

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:s="clr-namespace:System;assembly=mscorlib"
        xmlns:local="clr-namespace:MyNamespace">
  <Window.Resources>
    <DataTemplate DataType="{x:Type local:Person}">
      <Grid DataContext="{ViewModel}">
        <StackPanel>
          <TextBox Text="{Binding FirstName}" /> <!-- updates ViewModel on LostFocus event -->
          <TextBox Text="{Binding LastName, UpdateSourcheTrigger=PropertyChanged}" /> <!-- updates ViewModel on every property change -->
        </StackPanel>
      </Grid>
    </DataTemplate>
  </Window.Resources>
  
  <StackPanel>
    <ContentControl Content="{Binding}" />
  </StackPanel>
</Window>

Item List

// in constructor 
InitializeComponent();
var people = new List<Person> { ... }; 
DataContext = people;

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:s="clr-namespace:System;assembly=mscorlib"
        xmlns:local="clr-namespace:MyNamespace">
  <Window.Resources>
    <DataTemplate DataType="{x:Type local:Person}">
      <Grid DataContext="{ViewModel}">
        <StackPanel>
          <TextBox Text="{Binding FirstName}" /> <!-- updates ViewModel on LostFocus event -->
          <TextBox Text="{Binding LastName, UpdateSourcheTrigger=PropertyChanged}" /> <!-- updates ViewModel on every property change -->
        </StackPanel>
      </Grid>
    </DataTemplate>
  </Window.Resources>
  
  <StackPanel>
    <ListBox ItemsSource="{Binding}" />
  </StackPanel>
</Window>

Benutzer:MovGP0/WPF/Data Binding

Inhaltsverzeichnis

WPF Data Binding

Data Sources

Binding Properties

Binding to Control

Binding to an static .NET object

Binding to an resource

Binding to an DataContext

Binding to an ViewModel

Data Template

Navigationsmenü

Benutzer:MovGP0/WPF/Data Binding

WPF Data Binding

Data Sources

Binding Properties

Binding to Control

Binding to an static .NET object

Binding to an resource

Binding to an DataContext

Binding to an ViewModel

Data Template

Navigationsmenü

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