问题
I have a dependency property defined in my window as below:
public static readonly DependencyProperty IsGenericUserProperty = DependencyProperty.Register("IsGenericUser", typeof (bool), typeof (MainWindow));
public bool IsGenericUser
{
get { return (bool) GetValue(IsGenericUserProperty); }
set { SetValue(IsGenericUserProperty, value); }
}
On my window's constructor I set the data context of the container holding the button:
QuickListButtonsStackPanel.DataContext = this;
I am binding the dependency property to the IsEnabled property of a button:
<Button IsEnabled="{Binding IsGenericUser}" .../>
At startup IsGenericUser is true, so the button is enabled. When I set IsGenericUser to false, the button gets disabled. However, if I make IsGenericUser true again, nothing happens to the button and it remains disabled. What am I doing wrong?
Thanks!
edit: Here is the style I am using with the button. This style is causing the issue (if the button has no custom style it works fine):
<Style x:Key="BlackButtonStyle" TargetType="{x:Type Button}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<ControlTemplate.Resources>
<Storyboard x:Key="MouseOverActivating">
<ColorAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="rectangle" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
<SplineColorKeyFrame KeyTime="00:00:00" Value="#FF2F2F2F"/>
<SplineColorKeyFrame KeyTime="00:00:00.1270000" Value="#FF2391FF"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="MouseOverDeactivating">
<ColorAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="rectangle">
<SplineColorKeyFrame KeyTime="00:00:00" Value="#FF2391FF"/>
<SplineColorKeyFrame KeyTime="00:00:00.2200000" Value="#FF2F2F2F"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="PressActivating">
<ColorAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="rectangle" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
<SplineColorKeyFrame KeyTime="00:00:00" Value="#FF2391FF"/>
<SplineColorKeyFrame KeyTime="00:00:00.1370000" Value="#FF48D6FF"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="PressedDeactivating" FillBehavior="Stop" >
<ColorAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="rectangle">
<SplineColorKeyFrame KeyTime="00:00:00" Value="#FF48D6FF"/>
<SplineColorKeyFrame KeyTime="00:00:00.2370000" Value="#FF2391FF"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="DisableActivating">
<ColorAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="rectangle" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
<SplineColorKeyFrame KeyTime="00:00:00" Value="#FFA7A7A7"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
</ControlTemplate.Resources>
<Grid>
<Rectangle Stroke="Transparent" RadiusX="5" RadiusY="5" x:Name="rectangle">
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FF000000" Offset="0"/>
<GradientStop Color="#FF2F2F2F" Offset="1"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" RecognizesAccessKey="True" OpacityMask="{x:Null}"/>
<Rectangle Stroke="Transparent" RadiusX="5" RadiusY="5" x:Name="WhiteGlow">
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#5BFFFFFF" Offset="0"/>
<GradientStop Color="#00FFFFFF" Offset="0.5"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsCancel" Value="False"/>
<EventTrigger RoutedEvent="FrameworkElement.Loaded"/>
<Trigger Property="IsFocused" Value="True">
<Trigger.ExitActions>
<BeginStoryboard Storyboard="{StaticResource MouseOverActivating}" x:Name="MouseOverActivating_BeginStoryboard2"/>
</Trigger.ExitActions>
<Trigger.EnterActions>
<BeginStoryboard Storyboard="{StaticResource MouseOverActivating}" x:Name="MouseOverActivating_BeginStoryboard1"/>
</Trigger.EnterActions>
</Trigger>
<Trigger Property="IsDefaulted" Value="True"/>
<Trigger Property="IsMouseOver" Value="True">
<Trigger.ExitActions>
<BeginStoryboard Storyboard="{StaticResource MouseOverDeactivating}" x:Name="MouseOverDeactivating_BeginStoryboard"/>
</Trigger.ExitActions>
<Trigger.EnterActions>
<BeginStoryboard Storyboard="{StaticResource MouseOverActivating}" x:Name="MouseOverActivating_BeginStoryboard"/>
</Trigger.EnterActions>
</Trigger>
<Trigger Property="IsPressed" Value="True">
<Trigger.EnterActions>
<BeginStoryboard x:Name="PressActivating_BeginStoryboard" Storyboard="{StaticResource PressActivating}"/>
</Trigger.EnterActions>
<Trigger.ExitActions>
<BeginStoryboard x:Name="PressedDeactivating_BeginStoryboard" Storyboard="{StaticResource PressedDeactivating}"/>
</Trigger.ExitActions>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Trigger.EnterActions>
<BeginStoryboard Storyboard="{StaticResource DisableActivating}" x:Name="DisableActivating_BeginStoryboard"/>
</Trigger.EnterActions>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
回答1:
How are you setting the property to False/True? If I copy your code in as-is, it works perfectly. There has to be something else going on that you may not expect to effect it, like an animation on the button or something that is clearing the binding. Is there more code that you can post that may help clarify what could be doing this?
Here's the code I tested as well:
<Window x:Class="WpfApplication6.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1"
Height="300"
Width="300">
<Grid>
<StackPanel x:Name="QuickListButtonsStackPanel">
<Button IsEnabled="{Binding IsGenericUser}"
Content="Bound Button" />
<Button Content="Change Binding"
Click="Button_Click" />
</StackPanel>
</Grid>
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
QuickListButtonsStackPanel.DataContext = this;
}
public static readonly DependencyProperty IsGenericUserProperty =
DependencyProperty.Register(
"IsGenericUser",
typeof(bool),
typeof(Window1));
public bool IsGenericUser
{
get { return (bool)GetValue(IsGenericUserProperty); }
set { SetValue(IsGenericUserProperty, value); }
}
private void Button_Click(object sender, RoutedEventArgs e)
{
IsGenericUser = !IsGenericUser;
}
}
EDIT: You can add a text box as well to see if it is working,
<Button x:Name="uiButton"
IsEnabled="{Binding IsGenericUser}"
Style="{StaticResource BlackButtonStyle}"
Content="Bound Button"/>
<TextBlock Text="{Binding ElementName=uiButton, Path=IsEnabled}" />
It looks like the problem is just with the style's storyboards, if you add that, does it still show that IsEnabled is false when it shouldn't be?
回答2:
Try
<Button IsEnabled={Binding Path=IsGenericUser}" ... />
The Path= shouldn't be required, but it might make a differerce.
And by using the this in the data context, are you sure that's right? Wouldn't that make the control itself to the context. I've not seen the rest of your code, but that just doesn't seem right.
回答3:
1) Created a new storyboard called DisableDeactivating and set the FillBehavior="Stop" (Nicholas' suggestion) 2) Then, added a BeginStoryboard for DisableDeactivating in the Trigger.ExitActions of the IsEnabled = false trigger.
回答4:
If anyone encounters the same problem - it's very possible your DataContext isn't set or is dynamically changed to another Object. It happens in some Templates that contain a lot of diverse Controls.
来源：https://stackoverflow.com/questions/966274/wpf-isenabled-binding-to-dependencyproperty-not-working-properly