Question

我现在在app.xaml中拥有以下工作代码......

<Style x:Key="likeActionButton" TargetType="ToggleButton">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ToggleButton">
                        <Grid>
                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal">
                                    </VisualState>
                                    <VisualState x:Name="PointerOver">
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames
                                                Storyboard.TargetName="HoverBackground"
                                                Storyboard.TargetProperty = "Visibility">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Pressed">
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames
                                                Storyboard.TargetName="PressedBackground"
                                                Storyboard.TargetProperty = "Visibility">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <Border>
                                <Grid>
                                    <Image Width="25" Source="ms-appx:///Assets\ActionIcons\like-action.png"></Image>
                                    <Image x:Name="HoverBackground" Width="25" Source="ms-appx:///Assets\ActionIcons\like-action-onHover.png" Visibility="Collapsed"></Image>
                                    <Image x:Name="PressedBackground" Width="25" Source="ms-appx:///Assets\ActionIcons\like-action-on-pressed.png" Visibility="Collapsed"></Image>
                                </Grid>
                            </Border>
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

我用以下方式调用此模板：

<ToggleButton Grid.Column="4" HorizontalAlignment="Center" 
                                          Style="{StaticResource likeActionButton}" 
                                          IsChecked="{Binding LikeState}"  
                                          Tapped="Favourite_Tapped"></ToggleButton>

LikeState的绑定并不像我希望的那样完美。

很难解释，但我会尝试一下......

我可以选择并取消选择ToggleButton，背景图片将始终翻转。 LikeState后面的绑定似乎适用于属性，但不适用于图像。这意味着当数据加载时，布尔LikeState = true属性ToggleButton.IsChecked = true，但背景图像是VisualState x:Name="Normal"的图像。

再说一遍...... 我用LikeState = true加载数据。如果我第一次在ToggleButton上单击，则背景图像不会更改，但代码隐藏文件会执行isChecked = true的代码单击ToggleButton上的第二次确实会将背景图像更改为VisualState x:Name="Pressed"

那么我需要做些什么来设置依赖于动态填充属性的正确背景图像isChecked={Binding LikeState}

干杯，

克里斯

Answer 1

在绑定中尝试Mode=TwoWay。由于您在代码后面更改了有界属性值，为了反映在视图中您必须将Mode作为TwoWay

<强>更新

我检查了你的代码。没有双向绑定它只是工作正常。

使用视觉状态已选中

<VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal"/>
                                    <VisualState x:Name="PointerOver"/>
                                    <VisualState x:Name="Pressed"/>
                                    <VisualState x:Name="Disabled">
                                      </VisualState>
                                    <VisualState x:Name="Checked">
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames
                                                Storyboard.TargetName="PressedBackground"
                                                Storyboard.TargetProperty = "Visibility">
                                                <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                                            </ObjectAnimationUsingKeyFrames>
                                           </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="CheckedPointerOver">

                                    </VisualState>
                                    <VisualState x:Name="CheckedPressed"/>
                                    <VisualState x:Name="CheckedDisabled">
                                    </VisualState>
                                    <VisualState x:Name="Indeterminate"/>
                                    <VisualState x:Name="IndeterminatePointerOver"/>
                                    <VisualState x:Name="IndeterminatePressed"/>
                                    <VisualState x:Name="IndeterminateDisabled">
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>

希望您为LikeState属性实现INotifyPropertyChanged，以便最初检查它。如果没有，请执行以下操作。这就是我做的事情

 public sealed partial class MainPage : Page, INotifyPropertyChanged
    {
        bool likeState=true;
        public bool LikeState 
        {
            get { return likeState; }
            set
            {
                if(value!=likeState)
                {
                    value = likeState;
                    OnPropertyChanged("LikeState");
                }
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        void OnPropertyChanged(string propertyName)
        {
           if(this.PropertyChanged!=null)
                this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));

        }
        public MainPage()
        {
            this.InitializeComponent();

            this.NavigationCacheMode = NavigationCacheMode.Required;
            LikeState = true;
            toggle.DataContext = this;

        }
}

XAML ToggleButton使用isChecked更改背景图像= {Binding xyz}

1 个答案: