Need Help

[jedialpha]

I'd like to programm an DirectX DLL that I call from a C# Program
In the C# program i call the init function from the Dll with the handle of the C# window so DirectX can draw on the C# Window.
Below there's my code. when i call the RenderFrame function the C# window background becomes blue but no triangle was painted.
Why? Where's my error?

 #include "stdafx.h"
#include <d3d11.h>
#include <d3dx11.h>
#include <d3dx10.h>

// include the Direct3D Library file
#pragma comment (lib, "d3d11.lib")
#pragma comment (lib, "d3dx11.lib")
#pragma comment (lib, "d3dx10.lib")

// global declarations
IDXGISwapChain *swapchain;             // the pointer to the swap chain interface
ID3D11Device *dev;                     // the pointer to our Direct3D device interface
ID3D11DeviceContext *devcon;           // the pointer to our Direct3D device context
ID3D11RenderTargetView *backbuffer;    // global declaration
ID3D11InputLayout *pLayout;            // the pointer to the input layout
ID3D11VertexShader *pVS;               // the pointer to the vertex shader
ID3D11PixelShader *pPS;                // the pointer to the pixel shader
ID3D11Buffer *pVBuffer;                // the pointer to the vertex buffer

// a struct to define a single vertex
struct VERTEX{ FLOAT X, Y, Z; D3DXCOLOR Color; };

// function prototypes

void CleanD3D(void);         // closes Direct3D and releases memory
void InitGraphics(void);    // creates the shape to render
void InitPipeline(void);    // loads and prepares the shaders
void RenderFrame(void);


//extern "C" void _declspec(dllexport) init(long handle, int breite, int hoehe);

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
					 )
{
	switch (ul_reason_for_call)
	{
	case DLL_PROCESS_ATTACH:
	case DLL_THREAD_ATTACH:
	case DLL_THREAD_DETACH:
	case DLL_PROCESS_DETACH:
		break;
	}
	return TRUE;
}

extern "C" void _declspec(dllexport) init(long handle, int breite, int hoehe)
{
	// create a struct to hold information about the swap chain
	DXGI_SWAP_CHAIN_DESC scd;

	// clear out the struct for use
	ZeroMemory(&scd, sizeof(DXGI_SWAP_CHAIN_DESC));

	// fill the swap chain description struct
	scd.BufferCount = 1;                                    // one back buffer
	scd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;     // use 32-bit color
	scd.BufferDesc.Width = breite;                    // set the back buffer width
	scd.BufferDesc.Height = hoehe;                  // set the back buffer height
	scd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;      // how swap chain is to be used
	scd.OutputWindow = (HWND)handle;                                // the window to be used
	scd.SampleDesc.Count = 4;                               // how many multisamples
	scd.Windowed = TRUE;                                    // windowed/full-screen mode

	// create a device, device context and swap chain using the information in the scd struct
	D3D11CreateDeviceAndSwapChain(NULL,
		D3D_DRIVER_TYPE_HARDWARE,
		NULL,
		NULL,
		NULL,
		NULL,
		D3D11_SDK_VERSION,
		&scd,
		&swapchain,
		&dev,
		NULL,
		&devcon);


	// get the address of the back buffer
	ID3D11Texture2D *pBackBuffer;
	swapchain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);

	// use the back buffer address to create the render target
	dev->CreateRenderTargetView(pBackBuffer, NULL, &backbuffer);
	pBackBuffer->Release();

	// set the render target as the back buffer
	devcon->OMSetRenderTargets(1, &backbuffer, NULL);


	// Set the viewport
	D3D11_VIEWPORT viewport;
	ZeroMemory(&viewport, sizeof(D3D11_VIEWPORT));

	viewport.TopLeftX = 0;
	viewport.TopLeftY = 0;
	viewport.Width = breite;
	viewport.Height = hoehe;

	devcon->RSSetViewports(1, &viewport);

	InitPipeline();
	InitGraphics();
}

// this is the function used to render a single frame
void RenderFrame(void)
{
	// clear the back buffer to a deep blue
	devcon->ClearRenderTargetView(backbuffer, D3DXCOLOR(0.0f, 0.2f, 0.4f, 1.0f));

	// select which vertex buffer to display
	UINT stride = sizeof(VERTEX);
	UINT offset = 0;
	devcon->IASetVertexBuffers(0, 1, &pVBuffer, &stride, &offset);

	// select which primtive type we are using
	devcon->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

	// draw the vertex buffer to the back buffer
	devcon->Draw(3, 0);

	// switch the back buffer and the front buffer
	swapchain->Present(0, 0);
}

// this is the function that cleans up Direct3D and COM
void CleanD3D()
{
	// close and release all existing COM objects
	pLayout->Release();
	pVS->Release();
	pPS->Release();
	pVBuffer->Release();
	swapchain->Release();
	backbuffer->Release();
	dev->Release();
	devcon->Release();
}

// this is the function that creates the shape to render
void InitGraphics()
{
	// create a triangle using the VERTEX struct
	VERTEX OurVertices[] =
	{
		{ 0.0f, 0.9f, 0.0f, D3DXCOLOR(1.0f, 0.0f, 0.0f, 1.0f) },
		{ 0.45f, -0.5, 0.0f, D3DXCOLOR(0.0f, 1.0f, 0.0f, 1.0f) },
		{ -0.45f, -0.5f, 0.0f, D3DXCOLOR(0.0f, 0.0f, 1.0f, 1.0f) }
	};


	// create the vertex buffer
	D3D11_BUFFER_DESC bd;
	ZeroMemory(&bd, sizeof(bd));

	bd.Usage = D3D11_USAGE_DYNAMIC;                // write access access by CPU and GPU
	bd.ByteWidth = sizeof(VERTEX)* 3;             // size is the VERTEX struct * 3
	bd.BindFlags = D3D11_BIND_VERTEX_BUFFER;       // use as a vertex buffer
	bd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;    // allow CPU to write in buffer

	dev->CreateBuffer(&bd, NULL, &pVBuffer);       // create the buffer


	// copy the vertices into the buffer
	D3D11_MAPPED_SUBRESOURCE ms;
	devcon->Map(pVBuffer, NULL, D3D11_MAP_WRITE_DISCARD, NULL, &ms);    // map the buffer
	memcpy(ms.pData, OurVertices, sizeof(OurVertices));                 // copy the data
	devcon->Unmap(pVBuffer, NULL);                                      // unmap the buffer
}


// this function loads and prepares the shaders
void InitPipeline()
{
	// load and compile the two shaders
	ID3D10Blob *VS, *PS;
	D3DX11CompileFromFile(L"shaders.shader", 0, 0, "VShader", "vs_4_0", 0, 0, 0, &VS, 0, 0);
	D3DX11CompileFromFile(L"shaders.shader", 0, 0, "PShader", "ps_4_0", 0, 0, 0, &PS, 0, 0);

	// encapsulate both shaders into shader objects
	dev->CreateVertexShader(VS->GetBufferPointer(), VS->GetBufferSize(), NULL, &pVS);
	dev->CreatePixelShader(PS->GetBufferPointer(), PS->GetBufferSize(), NULL, &pPS);

	// set the shader objects
	devcon->VSSetShader(pVS, 0, 0);
	devcon->PSSetShader(pPS, 0, 0);

	// create the input layout object
	D3D11_INPUT_ELEMENT_DESC ied[] =
	{
		{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 },
		{ "COLOR", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0, 12, D3D11_INPUT_PER_VERTEX_DATA, 0 },
	};

	dev->CreateInputLayout(ied, 2, VS->GetBufferPointer(), VS->GetBufferSize(), &pLayout);
	devcon->IASetInputLayout(pLayout);
}

And the C# program:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Diagnostics;
using System.Runtime.InteropServices;
namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        [DllImport("Win32Project2.dll")]
        public static extern int init(long hWnd, int breite, int hoehe);
        [DllImport("Win32Project2.dll")]
        public static extern void RenderFrame();

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            init((long)this.Handle, this.Width, this.Height);

        }

        private void button2_Click(object sender, EventArgs e)
        {
            RenderFrame();
        }
    }
}