Question

我正在创建一个UserControl，我希望它有一个行为，当用户将鼠标滚轮旋转到它上面时，背景图像会在两个选项之间交替显示。

到目前为止我所拥有的是：

<UserControl x:Class="OI.MR.UserControls.DataControls.ScrollWheel"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             d:DesignHeight="400" d:DesignWidth="118">
    <UserControl.Background>
        <ImageBrush ImageSource="dial1.png" TileMode="None" />
    </UserControl.Background>
    <UserControl.InputBindings>
        <MouseBinding MouseAction="WheelClick" Command="{Binding ScrollTheWheel}"/>
    </UserControl.InputBindings>
</UserControl>

和

public partial class ScrollWheel : UserControl
{
    private bool _isDial1 = true;

    public ScrollWheel()
    {
        InitializeComponent();
    }

    private ICommand _scrollTheWheel;
    public ICommand ScrollTheWheel
    {
        get
        {
            if(_scrollTheWheel == null)
            {
                _scrollTheWheel = new DelegateCommand(_ => SwitchImage(), _ => true);
            }
            return _scrollTheWheel;
        }
    }

    private void SwitchImage()
    {
        if(_isDial1)
        {
            (Background as ImageBrush).ImageSource = new BitmapImage(new Uri("dial2.png"));
            _isDial1 = false;
        }
        else
        {
            (Background as ImageBrush).ImageSource = new BitmapImage(new Uri("dial1.png"));
            _isDial1 = true;   
        }
    }
}

然而转动方向盘并未改变背景图像。如何更改图像？

Answer 1

你的datacontext真的不对：一种可能性：

<UserControl.InputBindings>
    <MouseBinding MouseAction="WheelClick" 
        Command="{Binding Path=ScrollTheWheel, RelativeSource={RelativeSource AncestorType={x:Type view:YourUserControl}}}"/>
</UserControl.InputBindings>

（将类型替换为用户控件的类型）

如何让鼠标滚轮更改背景图像

1 个答案: