Here is a class that load D2DBitmap and draw it.

class YHMSprite
{
public:
	YHMSprite(const std::shared_ptr<DX::DeviceResources>& deviceResources);
	//YHMSprite(const std::shared_ptr<DX::DeviceResources>& deviceResources, LPCWSTR fileName);
	//YHMSprite(const std::shared_ptr<DX::DeviceResources>& deviceResources, Platform::String^ fileName);
	~YHMSprite();
	void LoadResource(LPCWSTR fileName);
	void Draw(float scale, float x, float y);
	void Draw(float scaleX, float scaleY, float x, float y);
	void Draw(float scaleX, float scaleY, float x, float y, float opacity);
	D2D1_SIZE_F GetBitmapSize();
private:
	std::shared_ptr<DX::DeviceResources> mDeviceResources;
	bool mIsResourceLoaded;
	ID2D1DrawingStateBlock *mStateBlock;
	ID2D1Bitmap *mBitmap;
	D2D1_SIZE_F	mBitmapSize;
};

And I create these resource

YHMSprite::YHMSprite(const std::shared_ptr<DX::DeviceResources>& deviceResources)
{
	mIsResourceLoaded = false;
	mDeviceResources = deviceResources;
	mDeviceResources->GetD2DFactory()->CreateDrawingStateBlock(&mStateBlock);
}

void YHMSprite::LoadResource(LPCWSTR fileName)
{
	ComPtr<IWICBitmapDecoder> wicBitmapDecoder;
	mDeviceResources->GetWicImagingFactory()->CreateDecoderFromFilename(fileName, nullptr, GENERIC_READ, WICDecodeMetadataCacheOnDemand, &wicBitmapDecoder);
	ComPtr<IWICBitmapFrameDecode> wicBitmapFrame;
	wicBitmapDecoder->GetFrame(0, &wicBitmapFrame);
	ComPtr<IWICFormatConverter> wicFormatConverter;
	mDeviceResources->GetWicImagingFactory()->CreateFormatConverter(&wicFormatConverter);
	wicFormatConverter->Initialize(wicBitmapFrame.Get(), GUID_WICPixelFormat32bppPBGRA, WICBitmapDitherTypeNone, nullptr, 0.0, WICBitmapPaletteTypeCustom);
	double DpiX = 72.0f, DpiY = 72.0f;
	wicFormatConverter->GetResolution(&DpiX, &DpiY);
	mDeviceResources->GetD2DDeviceContext()->CreateBitmapFromWicBitmap(wicFormatConverter.Get(), BitmapProperties(PixelFormat(DXGI_FORMAT_B8G8R8A8_UNORM, D2D1_ALPHA_MODE_PREMULTIPLIED), static_cast<float>(DpiX), static_cast<float>(DpiY)), &mBitmap);
	mBitmapSize = mBitmap->GetSize();
	mIsResourceLoaded = true;
}

In my code, I release these resource using this destruction function

YHMSprite::~YHMSprite()

after delete test set it to null. So...

delete test;

test = null;

But it doesn't release test completed!