WP7备注(33)(DataContext)
2011-05-03 14:39 血糯米Otomii 阅读(448) 评论(0) 编辑 收藏 举报DataContext为所有内部元素提供所需要的数据源
实例1:
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> <StackPanel DataContext="{Binding Source={StaticResource clock}}" Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center"> <TextBlock Text="{Binding Path=Hour}" /> <TextBlock Text="{Binding Path=Minute, Converter={StaticResource stringFormat}, ConverterParameter=':{0:D2}'}" /> <TextBlock Text="{Binding Path=Second, Converter={StaticResource stringFormat}, ConverterParameter=':{0:D2}'}" /> </StackPanel> </Grid>
实例2:
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> <StackPanel DataContext="{Binding Source={StaticResource clock}}" Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center"> <TextBlock Text="{Binding Hour}" /> <TextBlock Text="{Binding Minute, Converter={StaticResource stringFormat}, ConverterParameter=':{0:D2}'}" /> <TextBlock Text="{Binding Second, Converter={StaticResource stringFormat}, ConverterParameter=':{0:D2}'}" /> </StackPanel> </Grid>
实例3:
<Border DataContext="{Binding ElementName=this}" Background="{Binding Background}" BorderBrush="{Binding BorderBrush}" BorderThickness="{Binding BorderThickness}" CornerRadius="{Binding CornerRadius}" Padding="{Binding Padding}"> <TextBlock Text="{Binding Path=Text}" TextAlignment="{Binding Path=TextAlignment}" TextDecorations="{Binding Path=TextDecorations}" TextWrapping="{Binding ElementName=this, Path=TextWrapping}" /> </Border>
实例4:
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> <StackPanel DataContext="{StaticResource clock}" HorizontalAlignment="Center" VerticalAlignment="Center"> <StackPanel Orientation="Horizontal"> <TextBlock Text="It's day number " /> <TextBlock Text="{Binding Date.Day}" /> <TextBlock Text=" of month " /> <TextBlock Text="{Binding Date.Month}" /> </StackPanel> <StackPanel Orientation="Horizontal"> <TextBlock Text=" of the year " /> <TextBlock Text="{Binding Date.Year}" /> <TextBlock Text=", a " /> <TextBlock Text="{Binding Date.DayOfWeek}" /> <TextBlock Text="." /> </StackPanel> </StackPanel> </Grid>
实例5:
public class TwelveHourClock : Clock { int hour12; bool isam, ispm; public int Hour12 { protected set { if (value != hour12) { hour12 = value; OnPropertyChanged(new PropertyChangedEventArgs("Hour12")); } } get { return hour12; } } public bool IsAm { protected set { if (value != isam) { isam = value; OnPropertyChanged(new PropertyChangedEventArgs("IsAm")); } } get { return isam; } } public bool IsPm { protected set { if (value != ispm) { ispm = value; OnPropertyChanged(new PropertyChangedEventArgs("IsPm")); } } get { return ispm; } } protected override void OnPropertyChanged(PropertyChangedEventArgs args) { if (args.PropertyName == "Hour") { Hour12 = (Hour - 1) % 12 + 1; IsAm = Hour < 12; IsPm = !IsAm; } base.OnPropertyChanged(args); } }
public class BooleanToVisibilityConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { return (bool)value ? Visibility.Visible : Visibility.Collapsed; } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { return (Visibility)value == Visibility.Visible; } }
<phone:PhoneApplicationPage.Resources> <petzold:TwelveHourClock x:Key="clock12" /> <petzold:BooleanToVisibilityConverter x:Key="booleanToVisibility" /> </phone:PhoneApplicationPage.Resources> <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> <StackPanel DataContext="{StaticResource clock12}" Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center"> <TextBlock Text="It's after " /> <TextBlock Text="{Binding Hour}" /> <TextBlock Text=" in the morning." Visibility="{Binding IsAm, Converter={StaticResource booleanToVisibility}}" /> <TextBlock Text=" in the afternoon." Visibility="{Binding IsPm, Converter={StaticResource booleanToVisibility}}"/> </StackPanel> </Grid>
实例6:
public class Adder : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; double augend = 0; double addend = 0; double sum = 0; public double Augend { set { if (augend != value) { augend = value; OnPropertyChanged(new PropertyChangedEventArgs("Augend")); CalculateNewSum(); } } get { return augend; } } public double Addend { set { if (addend != value) { addend = value; OnPropertyChanged(new PropertyChangedEventArgs("Addend")); CalculateNewSum(); } } get { return addend; } } public double Sum { protected set { if (sum != value) { sum = value; OnPropertyChanged(new PropertyChangedEventArgs("Sum")); } } get { return sum; } } void CalculateNewSum() { Sum = Augend + Addend; } protected virtual void OnPropertyChanged(PropertyChangedEventArgs args) { if (PropertyChanged != null) PropertyChanged(this, args); } }
<phone:PhoneApplicationPage.Resources> <petzold:Adder x:Key="adder" /> <petzold:StringFormatConverter x:Key="stringFormat" /> </phone:PhoneApplicationPage.Resources> <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0" DataContext="{Binding Source={StaticResource adder}}"> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="*" /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <Slider Grid.Row="0" Minimum="-100" Maximum="100" Margin="24" Value="{Binding Augend, Mode=TwoWay}" /> <Slider Grid.Row="2" Minimum="-100" Maximum="100" Margin="24" Value="{Binding Addend, Mode=TwoWay}" /> <TextBlock Grid.Row="1" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="48" Text="{Binding Sum, Converter={StaticResource stringFormat}, ConverterParameter=' {0:F2} '}" /> </Grid>