WPF程序只能用XAML生成吗？

苏格拉底柏拉图

在MSDN的WPF部分的一些示例里，通常一个示例有两种实现方法：（1）用纯粹的XAML实现；（2）用C#语言实现。我在做实验时，如果是用纯粹的XAML来实现，完全正常。但是试图用C#实现时，则出问题：要是XAML部分置为空（企图用纯粹C#实现），则编译出错，系统提示“缺少根元素，XAML文件无效”；要是XAML部分不留空（例如就使用系统默认生成的XAML代码），则编译不出错，但运行时只有XAML部分起作用，C#代码有等于无。结果，一个示例我只能做到用纯粹XAML实现，而无法采用C#实现的方法。不知这究竟怎么回事。 以下是我在做“创建三维场景”实验时所企图使用的C#代码。如何才能让这些C#代码起作用，从而能通过C#代码实现功能呢？恳请各位大牛指教：
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Media3D;

namespace SDKSample
{
    public partial class Basic3DShapeExample : Page
    {
        public Basic3DShapeExample()
        {

            // Declare scene objects.
            Viewport3D myViewport3D = new Viewport3D();
            Model3DGroup myModel3DGroup = new Model3DGroup();
            GeometryModel3D myGeometryModel = new GeometryModel3D();            ModelVisual3D myModelVisual3D = new ModelVisual3D();
            // Defines the camera used to view the 3D object. In order to view the 3D object,
            // the camera must be positioned and pointed such that the object is within view
            // of the camera.
            PerspectiveCamera myPCamera = new PerspectiveCamera();

            // Specify where in the 3D scene the camera is.
            myPCamera.Position = new Point3D(0, 0, 2);

            // Specify the direction that the camera is pointing.
            myPCamera.LookDirection = new Vector3D(0, 0, -1);

            // Define camera's horizontal field of view in degrees.
            myPCamera.FieldOfView = 60;

            // Asign the camera to the viewport
            myViewport3D.Camera = myPCamera;
            // Define the lights cast in the scene. Without light, the 3D object cannot
            // be seen. Also, the direction of the lights affect shadowing. Note: to
            // illuminate an object from additional directions, create additional lights.
            DirectionalLight myDirectionalLight = new DirectionalLight();
            myDirectionalLight.Color = Colors.White;
            myDirectionalLight.Direction = new Vector3D(-0.61, -0.5, -0.61);

            myModel3DGroup.Children.Add(myDirectionalLight);

            // The geometry specifes the shape of the 3D plane. In this sample, a flat sheet
            // is created.
            MeshGeometry3D myMeshGeometry3D = new MeshGeometry3D();

            // Create a collection of normal vectors for the MeshGeometry3D.
            Vector3DCollection myNormalCollection = new Vector3DCollection();
            myNormalCollection.Add(new Vector3D(0,0,1));
            myNormalCollection.Add(new Vector3D(0,0,1));
            myNormalCollection.Add(new Vector3D(0,0,1));
            myNormalCollection.Add(new Vector3D(0,0,1));
            myNormalCollection.Add(new Vector3D(0,0,1));
            myNormalCollection.Add(new Vector3D(0,0,1));
            myMeshGeometry3D.Normals = myNormalCollection;

            // Create a collection of vertex positions for the MeshGeometry3D.
            Point3DCollection myPositionCollection = new Point3DCollection();
            myPositionCollection.Add(new Point3D(-0.5, -0.5, 0.5));
            myPositionCollection.Add(new Point3D(0.5, -0.5, 0.5));
            myPositionCollection.Add(new Point3D(0.5, 0.5, 0.5));
            myPositionCollection.Add(new Point3D(0.5, 0.5, 0.5));
            myPositionCollection.Add(new Point3D(-0.5, 0.5, 0.5));
            myPositionCollection.Add(new Point3D(-0.5, -0.5, 0.5));
            myMeshGeometry3D.Positions = myPositionCollection;

            // Create a collection of texture coordinates for the MeshGeometry3D.
            PointCollection myTextureCoordinatesCollection = new PointCollection();
            myTextureCoordinatesCollection.Add(new Point(0, 0));
            myTextureCoordinatesCollection.Add(new Point(1, 0));
            myTextureCoordinatesCollection.Add(new Point(1, 1));
            myTextureCoordinatesCollection.Add(new Point(1, 1));
            myTextureCoordinatesCollection.Add(new Point(0, 1));
            myTextureCoordinatesCollection.Add(new Point(0, 0));
            myMeshGeometry3D.TextureCoordinates = myTextureCoordinatesCollection;

            // Create a collection of triangle indices for the MeshGeometry3D.
            Int32Collection myTriangleIndicesCollection = new Int32Collection();
            myTriangleIndicesCollection.Add(0);
            myTriangleIndicesCollection.Add(1);
            myTriangleIndicesCollection.Add(2);
            myTriangleIndicesCollection.Add(3);
            myTriangleIndicesCollection.Add(4);
            myTriangleIndicesCollection.Add(5);
            myMeshGeometry3D.TriangleIndices = myTriangleIndicesCollection;

            // Apply the mesh to the geometry model.
            myGeometryModel.Geometry = myMeshGeometry3D;

            // The material specifies the material applied to the 3D object. In this sample a  
            // linear gradient covers the surface of the 3D object.

            // Create a horizontal linear gradient with four stops.   
            LinearGradientBrush myHorizontalGradient = new LinearGradientBrush();
            myHorizontalGradient.StartPoint = new Point(0, 0.5);
            myHorizontalGradient.EndPoint = new Point(1, 0.5);
            myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.Yellow, 0.0));
            myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.Red, 0.25));
            myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.Blue, 0.75));
            myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.LimeGreen, 1.0));

            // Define material and apply to the mesh geometries.
            DiffuseMaterial myMaterial = new DiffuseMaterial(myHorizontalGradient);
            myGeometryModel.Material = myMaterial;

            // Apply a transform to the object. In this sample, a rotation transform is applied,  
            // rendering the 3D object rotated.
            RotateTransform3D myRotateTransform3D = new RotateTransform3D();
            AxisAngleRotation3D myAxisAngleRotation3d = new AxisAngleRotation3D();
            myAxisAngleRotation3d.Axis = new Vector3D(0,3,0);
            myAxisAngleRotation3d.Angle = 40;
            myRotateTransform3D.Rotation = myAxisAngleRotation3d;
            myGeometryModel.Transform = myRotateTransform3D;

            // Add the geometry model to the model group.
            myModel3DGroup.Children.Add(myGeometryModel);

            // Add the group of models to the ModelVisual3d.
            myModelVisual3D.Content = myModel3DGroup;

            //
            myViewport3D.Children.Add(myModelVisual3D);

            // Apply the viewport to the page so it will be rendered.
            this.Content = myViewport3D;
        }
    }
}