如何设置将文本框绑定到不在数据上下文类中的类

Question

我有这个停靠面板，我正在尝试为其设置绑定。

问题是我的 XAML 的 DataContext 设置为 MainWindow 类，但我要绑定到的类 (autoCam) 与该类是分开的。我在 MainWindow 类中使用了一个名为“myCam”的 autoCam 实例，但我对如何让这些绑定起作用感到困惑。

这是我在停靠面板中使用的代码：

            <DockPanel  x:Name="BottomDock" Visibility="Collapsed" Grid.Column="2" Grid.Row="2" Grid.ColumnSpan="2" DockPanel.Dock="Bottom" Margin="0">
                <Button x:Name="Rewind" Click="Rewind_Click" HorizontalAlignment="Left" Width="23" RenderTransformOrigin="0.5,0.5" Grid.Row="1"/>
                <Button x:Name="Play" Content=">" Click="Play_Click" HorizontalAlignment="Left" Width="17" RenderTransformOrigin="0.5,0.5" Grid.Row="1"/>
                <Button x:Name="Pause" Content="||" Click ="Pause_Click" HorizontalAlignment="Left" VerticalAlignment="Top" Width="16" Height="22" RenderTransformOrigin="0.5,0.5" Grid.Row="1"/>
                <Button x:Name="FastForward" Content=">>" Click="FastForward_Click" HorizontalAlignment="Left" Width="23" RenderTransformOrigin="0.5,0.5" Grid.Row="1"/>
                <TextBlock Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="95" Text="Camera Position"/>
                <TextBox Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="40" Name="cpx" Text="{Binding Path=myCam.cameraPositionX, UpdateSourceTrigger=PropertyChanged}"/>
                <TextBox Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="40" Name="cpy" Text="{Binding Path=myCam.cameraPositionY, UpdateSourceTrigger=PropertyChanged}"/>
                <TextBox Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="40" Name="cpz" Text="{Binding Path=myCam.cameraPositionZ, UpdateSourceTrigger=PropertyChanged}"/>
                <TextBlock Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="95" Text="Look Direction"/>
                <TextBox Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="40" Name="ldx" Text="{Binding Path=myCam.lookDirectionX, UpdateSourceTrigger=PropertyChanged}"/>
                <TextBox Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="40" Name="ldy" Text="{Binding Path=myCam.lookDirectionY, UpdateSourceTrigger=PropertyChanged}"/>
                <TextBox Background="Black" TextAlignment="Center" Foreground="AliceBlue" HorizontalAlignment="Left" Width="40" Name="ldz" Text="{Binding Path=myCam.lookDirectionZ, UpdateSourceTrigger=PropertyChanged}"/>
            </DockPanel>

起初我以为我可以将 DataContext=autoCam 写为停靠面板本身的属性，或者为每个单独的文本框写，然后只说 {binding cameraPositionX} 或其他内容，但这没有任何作用。

然后我想我可以说 {Binding myCam.cameraPositionX} 因为 myCam 是 MainWindow 类的成员。但这也没有用。

在一次徒劳的尝试中，我尝试将我的猜测结合起来，并将 DataContext=autoCam 添加到所有文本框的属性中，但我从未想过这会真正起作用。

我还尝试在 datacontext=this; 之后写以下内容主窗口构造函数中的行。我尝试了这个，以防问题是 xaml 会按照我的需要正确设置数据上下文，但是当构造函数运行时，整个 ui 的数据上下文将重新应用到主窗口。

    public MainWindow()
    {
        InitializeComponent();
        Interval = new TimeSpan(0, 0, 0, 0, 10);
        Rewind.Content = "<<";
        runType = 2;
        timerRate(runType);
        Loaded += new RoutedEventHandler(MainWindow_Loaded);
        DataContext = this;
        cpx.DataContext = myCam;
        cpy.DataContext = myCam;
        cpx.DataContext = myCam;
        ldx.DataContext = myCam;
        ldy.DataContext = myCam;
        ldz.DataContext = myCam;
        //view1.IsHeadLightEnabled = true;
    }

我想也许我可以把它放在 Window.Resources XAML 中：

<Window.Resources>
    <ObjectDataProvider x:Key="Camera" ObjectType="{x:Type local:autoCam}" MethodName="getCamDetails"/>
</Window.Resources>

但我在我的 autoCam 类中编写了方法 getCamDetails，如下所示，每次我尝试将 CamDetails[0] 设置为 cameraPositionX 时，它都会给我一个空引用异常。

public class autoCam : INotifyPropertyChanged
{
    MainWindow mW;
    public static double[] CamDetails;

    public static double[] getCamDetails()
    {
        return CamDetails;
    }

    public Point3D cameraPosition
    {
        get { return mC.Position; }
        set
        {
            mC.Position = value;
            cameraPositionX = Convert.ToDouble(cameraPosition.X);
            cameraPositionY = Convert.ToDouble(cameraPosition.Y);
            cameraPositionZ = Convert.ToDouble(cameraPosition.Z);
            lookDirection = mC.LookDirection;
            lookDirectionX = Convert.ToDouble(lookDirection.X);
            lookDirectionY = Convert.ToDouble(lookDirection.Y);
            lookDirectionZ = Convert.ToDouble(lookDirection.Z);
            onPropertyChanged("cameraPosition");
        }
    }
    public double cameraPositionX
    {
        get { return Convert.ToDouble(cameraPosition.X); }
        set { onPropertyChanged("cameraPositionX"); CamDetails[0] = cameraPositionX; }
    }
    public double cameraPositionY
    {
        get { return Convert.ToDouble(cameraPosition.Y); }
        set { onPropertyChanged("cameraPositionY"); CamDetails[1] = cameraPositionY; }
    }
    public double cameraPositionZ
    {
        get { return Convert.ToDouble(cameraPosition.Z); }
        set { onPropertyChanged("cameraPositionZ"); CamDetails[2] = cameraPositionZ; }
    }
    public Vector3D lookDirection
    {
        get { return mC.LookDirection; }
        set {
            mC.LookDirection = value;
            lookDirectionX = Convert.ToDouble(lookDirection.X);
            lookDirectionY = Convert.ToDouble(lookDirection.Y);
            lookDirectionZ = Convert.ToDouble(lookDirection.Z);
            onPropertyChanged("lookDirection");
        }
    }
    public double lookDirectionX
    {
        get { return Convert.ToDouble(lookDirection.X);}
        set { onPropertyChanged("lookDirectionX"); CamDetails[3] = lookDirectionX; }
    }
    public double lookDirectionY
    {
        get { return Convert.ToDouble(lookDirection.Y); }
        set { onPropertyChanged("lookDirectionY"); CamDetails[4] = lookDirectionY; }
    }
    public double lookDirectionZ
    {
        get { return Convert.ToDouble(lookDirection.Z); }
        set { onPropertyChanged("lookDirectionZ"); CamDetails[5] = lookDirectionZ; }

我真的很感激一个解决方案，但从长远来看，分解为什么这些对我不起作用从本质上来说会帮助我更多。

感谢您抽出宝贵时间帮助大家。

Answer 1

最好也共享 MainWindow 类，但听起来像是在 MainWindow 类中放置一个属性以公开 myCam 实例并直接绑定到该属性应该可以工作。

public partial class MainWindow : Window
{
    private AutoCam autoCam;

    public AutoCam AutoCam
    {
        get { return autoCam; }
        set { autoCam = value; }
    }


    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = this;
        this.autoCam = new AutoCam();
    }
}

public class AutoCam
{
    private string someText;

    public string SomeText
    {
        get { return someText; }
        set { someText = value; }
    }

    public AutoCam()
    {
        this.SomeText = "Some Text";
    }

}

而且绑定会是这样的。

<Label Content="{Binding AutoCam.SomeText}">