如何在 WPF 代码中相对设置按钮位置

Question

在 WPF 中，我在 canvas 上创建按钮。像这样。

private void DrawBtnTag( List<ValPosCrt> tagPos) 
    {
        int posNum = tagPos.Count;

        StackPanel[] temp = new StackPanel[ posNum ];
        Button[] btn = new Button[posNum];

        for ( int i = 0 ; i < posNum ; i++ )
        {
            var btntemp = CheckButton(i);
            Canvas.SetLeft( btntemp , tagPos [ i ].X );
            Canvas.SetTop( btntemp , tagPos [ i ].Y );
            cvsMap.Children.Add( btntemp );
            btn [ i ] = btntemp;
        }
    }

    private Button CheckButton( int i ) // done 
    {
        var btn = new Button();
        btn.Name = "btn" + i.ToString();
        btn.Width = 20;
        btn.Height = 20;
        btn.VerticalAlignment = VerticalAlignment.Stretch;
        btn.HorizontalAlignment = HorizontalAlignment.Stretch;
        btn.Click += ClickIdx;
        return btn;
    }

但是当我运行此代码并扩展应用程序大小时，按钮位置不会更新。

第二张图片是扩展的应用程序大小，我创建的小按钮是行为锚定对象。我想让这个按钮跟随背景图像。

Xaml代码仅此

     <DockPanel Name="dckPanel" Margin="5" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
    <Border CornerRadius="6" BorderThickness="2" BorderBrush="RoyalBlue" DockPanel.Dock="Top" >
        <Grid>
            <Canvas Name="cvsMap" Grid.Column="0" ClipToBounds="True" Margin="15">
                <Canvas.Background>
                    <ImageBrush x:Name="imgMap" Stretch="Uniform"  RenderOptions.BitmapScalingMode="Fant"   />
                </Canvas.Background>
            </Canvas>
        </Grid>
    </Border>
</DockPanel>

我该如何解决这个问题？

** 更新：添加测试代码，修复 Xaml 代码。

这是wpf项目的测试代码

代码隐藏 -

public partial class MainWindow : Window

{ public 主窗口() { InitializeComponent();

    List<Point> inputdata = new List<Point>();
    inputdata.Add( new Point( 250 , 250 ) );
    inputdata.Add( new Point( 250 , 300 ) );
    inputdata.Add( new Point( 300 , 250 ) );
    inputdata.Add( new Point( 250 , 200 ) );
    inputdata.Add( new Point( 200 , 250 ) );
    DrawBtnTag( inputdata );


    imgMap.ImageSource = createImg();
}

private void DrawBtnTag( List<Point> tagPos ) // done
{
    int posNum = tagPos.Count;

    StackPanel[] temp = new StackPanel[ posNum ];
    Button[] btn = new Button[posNum];

    for ( int i = 0 ; i < posNum ; i++ )
    {
        var btntemp = CheckButton(i);
        Canvas.SetLeft( btntemp , tagPos [ i ].X );
        Canvas.SetTop( btntemp , tagPos [ i ].Y );
        cvsMap.Children.Add( btntemp );
        btn [ i ] = btntemp;
    }
}

private Button CheckButton( int i ) // done 
{
    var btn = new Button();
    btn.Name = "btn" + i.ToString();
    btn.Width = 20;
    btn.Height = 20;
    btn.VerticalAlignment = VerticalAlignment.Stretch;
    btn.HorizontalAlignment = HorizontalAlignment.Stretch;
    return btn;
}


public BitmapSource createImg()
{
    List<System.Windows.Media.Color> colors = new List<System.Windows.Media.Color>();
    colors.Add( System.Windows.Media.Colors.Red );
    colors.Add( System.Windows.Media.Colors.Blue );

    BitmapPalette palette = new BitmapPalette(colors);
    System.Windows.Media.PixelFormat pf =
        System.Windows.Media.PixelFormats.Indexed1;
    int width = 128;
    int height = width;
    int stride = width/pf.BitsPerPixel;

    byte[] pixels = new byte[height*stride];

    for ( int i = 0 ; i < height * stride ; ++i )
    {
        if ( i < height * stride / 2 )
        {
            pixels [ i ] = 0x00;
        }
        else
        {
            pixels [ i ] = 0xff;
        }
    }

    return  BitmapSource.Create(
        width,
        height,
        96,
        96,
        pf,
        palette,
        pixels,
        stride);

}

}

xaml代码- => 与上面的 xaml 代码相同。只需将该停靠面板放在 window 之后。像这样 window> .. 这里 ../window>

Answer 1

答案可能有点长，但无需修改即可。

基本上：

我为您的 Canvas
它计算背景图片的大小和位置（旧的和新的）
对于每个按钮，它计算背景图像的相对位置（旧的和新的）并修改它
关于宽高比有很多事情（以确保正确的行为），并且此代码只能使用统一的行为（Stretch="Uniform"）

这是修改后的 XAML 代码：

<Canvas Name="cvsMap" Grid.Column="0" ClipToBounds="True" Margin="15" SizeChanged="cvsMap_SizeChanged">
    <Canvas.Background>
        <ImageBrush x:Name="imgMap" Stretch="Uniform"  RenderOptions.BitmapScalingMode="Fant"   />
    </Canvas.Background>
</Canvas>

然后是后面的代码（copy/paste 在您的 createImg 函数之后）：

    private void cvsMap_SizeChanged(object sender, SizeChangedEventArgs e)
    {
        double ratio = imgMap.ImageSource.Width / imgMap.ImageSource.Height;

        foreach (Control ctrl in cvsMap.Children)
        {
            if (ctrl is Button)
            {
                newBtnPosition((Button)ctrl, ratio, e);
            }
        }
    }
    /// <summary>
    /// Assign a new position to a ctrl contained into a canvas
    /// </summary>
    /// <param name="ctrl">control to modify</param>
    /// <param name="ratio">ratio of the reference element</param>
    /// <param name="e">SizeChanged of the container</param>
    private void newBtnPosition(Control ctrl, double ratio, SizeChangedEventArgs e)
    {

        //Everythong is computed according to the reference element (ImageBrush)
        Size oldImgSize, newImgSize;

        //Avoid dividing by 0
        if (e.PreviousSize.Width * e.PreviousSize.Height * e.NewSize.Width * e.NewSize.Height == 0) { return; }

        oldImgSize = RefSize(ratio, e.PreviousSize);
        newImgSize = RefSize(ratio, e.NewSize);

        Point oldImgPos, newImgPos;
        oldImgPos = new Point((e.PreviousSize.Width - oldImgSize.Width) / 2, (e.PreviousSize.Height - oldImgSize.Height) / 2);
        newImgPos = new Point((e.NewSize.Width - newImgSize.Width) / 2, (e.NewSize.Height - newImgSize.Height) / 2);

        //Retrieve the position of the control according to the ref element
        Point ctrlPos = new Point((double)ctrl.GetValue(Canvas.LeftProperty) - oldImgPos.X,
                                 (double)ctrl.GetValue(Canvas.TopProperty) - oldImgPos.Y);

        //Compute the new position according to the reference element
        ctrlPos.X*=newImgSize.Width / oldImgSize.Width;
        ctrlPos.Y *= newImgSize.Height / oldImgSize.Height;

        //Assign the new position according to the Canvas
        ctrl.SetValue(Canvas.LeftProperty, ctrlPos.X + newImgPos.X);
        ctrl.SetValue(Canvas.TopProperty, ctrlPos.Y + newImgPos.Y);
    }

    /// <summary>
    /// Compute a element size, given a aspect ratio, a container size, and a Stretch="Uniform" behavior
    /// </summary>
    /// <param name="ratio">aspect ratio of the control</param>
    /// <param name="containerSize">container size of the control</param>
    /// <returns>new size</returns>
    private Size RefSize(double ratio, Size containerSize)
    {
        double cH, cW;
        cW = containerSize.Width;
        cH = containerSize.Height;

        if (cH * cW == 0) { return new Size(0, 0); }

        if (cW / cH  > ratio)
        {
            return new Size(cH * ratio, cH);
        }
        else
        {
            return new Size(cW, cW/ratio);
        }

    }

如何在 WPF 代码中相对设置按钮位置

How set button position relatively in code behind on WPF

c#

wpf

location

resize