绑定值无法正常工作

Question

I have code:

<ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background).   (GradientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="grid">
    <EasingColorKeyFrame KeyTime="0:0:0.5" Value="{Binding CorBackground}"/>
</ColorAnimationUsingKeyFrames>

color value is defined as Value="#FFFFFF" , I'll want to define this color using binding. Value="{Binding CorBackground} . It's possible?

I create a property in MainWindow.xaml.cs , but don't work:

private string _corBackground = string.Empty;
public string CorBackground
{
    get { return _corBackground; }
    set { _corBackground = value; }
}

Answer 1

If you don't want to use a MVVM-pattern with proper binding, a possible solution is to use a DependecyProperty in your UserControl (as in the example a SolidColorBrush Property called "BackgroundColor"). Your MainWindow.cs would look like

    public partial class MainWindow : Window
{
    public static readonly DependencyProperty BackgroundColorProperty = DependencyProperty.Register(
        "BackgroundColor", typeof (SolidColorBrush), typeof (MainWindow), new PropertyMetadata(default(SolidColorBrush)));

    public SolidColorBrush BackgroundColor
    {
        get { return (SolidColorBrush) GetValue(BackgroundColorProperty); }
        set { SetValue(BackgroundColorProperty, value); }
    }

    public MainWindow()
    {
        BackgroundColor = new SolidColorBrush(Colors.LightBlue);
        InitializeComponent();
    }

    private void ChangeBackgroundButton_OnClick(object sender, RoutedEventArgs e)
    {
        BackgroundColor = new SolidColorBrush(Colors.CornflowerBlue);
    }
}

Where your Grid Background Property is bound to "BackgroundColor".

<Window x:Class="ListBoxStackoverflow.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525"
    x:Name="WindowsWithDependencyProperty">

<Grid Background="{Binding ElementName=WindowsWithDependencyProperty, Path=BackgroundColor}">
    <Button x:Name="ChangeBackgroundButton" 
            HorizontalAlignment="Left" VerticalAlignment="Top"
            Click="ChangeBackgroundButton_OnClick">Change Background</Button>
</Grid>

Note that this is just one possible solution.

Answer 2

I am not sure if this property can be a bindable one but normally it should be. If so, you have to set the DataContext of the control to an instance of the class that contains your property.

If it is in the same control/window/class then a simple this.DataContext = this in the constructor or in the Loaded event of your control/window whatever will do the job for you.

Answer 3

The class needs to implement INotifyPropertyChanged, and the property needs to raise the PropertyChanged event in the set method for the binding to work properly.

Also make sure your object has the data context set to the code behind. One way to do this is in the xaml window declaration. Set the data context like this:

DataContext={Binding RelativeSource={RelativeSource.Self}}