C# WPF实现3D操作几何体效果

public MainWindow()
{
    InitializeComponent();
    KeyDown += MainWindow_KeyDown;
}

private void MainWindow_KeyDown(object sender, KeyEventArgs e)
{

    if ((Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl)) && Keyboard.IsKeyDown(Key.N))
    {
        MeshGeometry3D mesh = MakeCubeMesh(0, 0, 0, 1);
        Color color = Color.FromArgb(255, 0, 255, 0);
        DiffuseMaterial material = new DiffuseMaterial(new SolidColorBrush(color));
        GeometryModel3D model = new GeometryModel3D(mesh, material);
        group3d.Children.Add(model);
    }
}

<Window x:Class="MyWord.ParaDialog"
        xmlns="Http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="输入参数" Height="180" Width="300">
    <DockPanel LastChildFill="True">
        <StackPanel DockPanel.Dock="Bottom"
            Orientation="Horizontal" HorizontalAlignment="Right">
            <Button Content="设置" Click="okButton_Click" Margin="5" Width="60" Height="25"/>
            <Button Content="取消" IsCancel="True" Margin="5" Width="60" Height="25"/>
        </StackPanel>
        <UnifORMGrid Columns="1" Margin="5" x:Name="ufgLabel"/>
        <UniformGrid Columns="1" Margin="5" x:Name="ufgTextBox"/>

​​​​​​​    </DockPanel>
</Window>

public partial class ParaDialog : Window
{
    static readonly string[] labels = new string[4] { "x坐标", "y坐标", "z坐标", "边长" };
    List<TextBox> paraBoxes = new List<TextBox>();
    public double[] para;
    public ParaDialog(double[] para)
    {
        this.para = para;
        InitializeComponent();
        string tmp;
        for (int i = 0; i < 4; i++)
        {
            //向UniformGrid中欧给填充文字块
            ufgLabel.Children.Add(new TextBlock() { Text = labels[i] });
            paraBoxes.Add(new TextBox());
            ufgTextBox.Children.Add(paraBoxes[i]);
        }
    }

    private void okButton_Click(object sender, RoutedEventArgs e)
    {
        for (int i = 0; i < 4; i++)
            para[i] = double.Parse(paraBoxes[i].Text);
        DialogResult = true;
    }
}

//...前面不用改
if ((Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl)) && Keyboard.IsKeyDown(Key.N))
{
  double[] para = new double[4];
  ParaDialog pDialog = new ParaDialog(para);
  pDialog.ShowDialog();
  if (pDialog.DialogResult != true)
      return;
  MeshGeometry3D mesh = MakeCubeMesh(para[0],para[1],para[2],para[3]);
  //...后面不用改
}

<Border Name="mainBorder" Background="White" MouseDown="mainBorder_MouseDown">
    <Viewport3D x:Name="v3dMain">
    </Viewport3D>
</Border>

private void mainBorder_MouseDown(object sender, MouseButtonEventArgs e)
{
    if (e.LeftButton == MouseButtonState.Released) return;

    Color color = Color.FromArgb(255, 0, 255, 0);
    var material = new DiffuseMaterial(new SolidColorBrush(color));

    //获取鼠标在对象中的位置
    Point mousePos = e.GetPosition(v3dMain);

    // 执行点击操作
    HitTestResult result = VisualTreeHelper.HitTest(v3dMain, mousePos);

    //此即鼠标点击到曲面上的结果
    var meshResult = result as RayMeshGeometry3DHitTestResult;
    GeometryModel3D model = null;
    if ((meshResult != null) && (meshResult.ModelHit is GeometryModel3D))
        model = meshResult.ModelHit as GeometryModel3D;

    //如果刚才选了别的模型，则使之恢复绿色
    if (SelectedModel != null)
        SelectedModel.Material = material;
    //选择新的模型
    SelectedModel = model;
    if (model != null) 
        model.Material = new DiffuseMaterial(Brushes.Fuchsia);
}

//MainWindow_KeyDown函数
model.Transform = new TranslateTransform3D(0, 0, 0);

private Point3D oldPoint;

mainBorder.CaptureMouse();
mainBorder.MouseMove += MainBorder_MouseMove;
mainBorder.MouseUp += MainBorder_MouseUp;

private void MainBorder_MouseUp(object sender, MouseButtonEventArgs e)
{
    mainBorder.ReleaseMouseCapture();
    mainBorder.MouseMove -= MainBorder_MouseMove;
    mainBorder.MouseUp -= MainBorder_MouseUp;
}

private void MainBorder_MouseMove(object sender, MouseEventArgs e)
{
    Point newPoint = e.GetPosition(mainBorder);
    var res = VisualTreeHelper.HitTest(v3dMain, newPoint);
    if (res == null) return;
    var newResult = res as RayMeshGeometry3DHitTestResult;

    var deltaPt = newResult.PointHit - oldPoint;
    var trans = SelectedModel.Transform as TranslateTransform3D;
    trans.OffsetX += deltaPt.X;
    trans.OffsetY += deltaPt.Y;
    trans.OffsetZ += deltaPt.Z;
    oldPoint = newResult.PointHit;
}