夏普DX不绘图

我正在尝试使用SharpDX用C#编写一个简单的DirectX 11应用程序。我能够设置清晰的颜色，这很有效，但是当我尝试绘制多边形时，它们没有显示。我正在另一个源文件中创建一个新的Game类来创建窗口并绘制到它。

游戏.cs：

using System;
using System.Linq;
using System.Drawing;
using SharpDX.Windows;
using SharpDX.DXGI;
using SharpDX.Direct3D;
using SharpDX.D3DCompiler;
using SharpDX;
using DXMath = SharpDX.Mathematics.Interop;
using D3D11 = SharpDX.Direct3D11;
namespace testthing
{
    class Game : IDisposable
    {
        private RenderForm renderForm;
        private int width = 1280;
        private int height = 720;
        private D3D11.Device device;
        private D3D11.DeviceContext context;
        private SwapChain swapChain;
        private D3D11.RenderTargetView renderTarget;
        private DXMath.RawVector3[] verts;
        private D3D11.Buffer vertexBuffer;
        private D3D11.VertexShader vertShader;
        private D3D11.PixelShader pixelShader;
        private D3D11.InputElement[] inputElements = new D3D11.InputElement[]
        {
            new D3D11.InputElement("POSITION", 0, Format.R32G32B32_Float, 0)
        };
        private ShaderSignature inputSignature;
        private D3D11.InputLayout inputLayout;
        private DXMath.RawViewportF viewport;
        private double time = 0;
        public Game()
        {
            renderForm = new RenderForm("DxDemo");
            renderForm.ClientSize = new Size(width, height);
            renderForm.AllowUserResizing = false;
            InitDevice();
            verts = new DXMath.RawVector3[] { new DXMath.RawVector3(-0.5f,-0.5f,0.0f), new DXMath.RawVector3(0.5f, -0.5f, 0.0f), new DXMath.RawVector3(0.0f, 0.5f, 0.0f) };
            vertexBuffer = D3D11.Buffer.Create<DXMath.RawVector3>(device, D3D11.BindFlags.VertexBuffer, verts);
            CompileShaders();
            RenderLoop.Run(renderForm, Render);
        }
        private void InitDevice()
        {
            ModeDescription backBufferDesc = new ModeDescription(width, height, new Rational(60,1), Format.R8G8B8A8_UNorm);
            SwapChainDescription swapChainDesc = new SwapChainDescription()
            {
                ModeDescription = backBufferDesc,
                SampleDescription = new SampleDescription(1,0),
                Usage = Usage.RenderTargetOutput,
                BufferCount = 1,
                OutputHandle = renderForm.Handle,
                IsWindowed = true
            };
            D3D11.Device.CreateWithSwapChain(DriverType.Hardware, D3D11.DeviceCreationFlags.None, swapChainDesc, out device, out swapChain);
            context = device.ImmediateContext;
            using (D3D11.Texture2D backBuffer = swapChain.GetBackBuffer<D3D11.Texture2D>(0))
            {
                renderTarget = new D3D11.RenderTargetView(device, backBuffer);
            }
            context.OutputMerger.SetRenderTargets(renderTarget);
            viewport = new DXMath.RawViewportF()
            {
                X = 0,
                Y = 0,
                Width = width,
                Height = height
            };
            context.Rasterizer.SetViewport(viewport);
        }
        private void CompileShaders()
        {
            using (var vsBC = ShaderBytecode.CompileFromFile("vertex.hlsl", "main", "vs_4_0", ShaderFlags.Debug))
            {
                inputSignature = ShaderSignature.GetInputSignature(vsBC);
                vertShader = new D3D11.VertexShader(device, vsBC);
            }
            using (var psBC = ShaderBytecode.CompileFromFile("pixel.hlsl", "main", "ps_4_0", ShaderFlags.Debug))
            {
                pixelShader = new D3D11.PixelShader(device, psBC);
            }
            context.VertexShader.Set(vertShader);
            context.PixelShader.Set(pixelShader);
            inputLayout = new D3D11.InputLayout(device, inputSignature, inputElements);
            context.InputAssembler.InputLayout = inputLayout;
        }
        private void Render()
        {
            time = time + 0.01;
            context.ClearRenderTargetView(renderTarget, new DXMath.RawColor4(0.5f, 0.5f, 0.5f, 0.0f));
            context.InputAssembler.SetVertexBuffers(0, new D3D11.VertexBufferBinding(vertexBuffer, Utilities.SizeOf<DXMath.RawVector3>(), 0));
            context.Draw(verts.Count(), 0);
            swapChain.Present(1, PresentFlags.None);
        }

        public void Dispose()
        {
            inputLayout.Dispose();
            inputSignature.Dispose();
            vertexBuffer.Dispose();
            vertShader.Dispose();
            pixelShader.Dispose();
            renderTarget.Dispose();
            swapChain.Dispose();
            device.Dispose();
            context.Dispose();
            renderForm.Dispose();
        }
    }
}

vertex.hlsl：

float4 main(float4 position : POSITION) : SV_POSITION
{
    return position;
}

pixel.hlsl：

float4 main(float4 position : SV_POSITION) : SV_TARGET
{
    return float4(1.0,0.0,0.0,1.0);
}

编辑：事实证明渲染目标视图没有被绑定，即使我正在调用context.OutputMerger.SetRenderTargets(renderTarget)。