Reference to type 'MarshalByRefObject' claims it is defined in 'mscorlib', but it could not be found.

I'm working on a windows universal app with visual studio 2015. But I meet the error when I tried to use GetPixel in System.drawing.Imaging. I can't find the solution for this problem. Anyone has met the same problem and have a solution?
Thanks in advance!

Color imagecolor;
float[,] imagegray = new float[image.Width, image.Height];
for (int i = 0; i < image.Width; i++)
{
    for (int j = 0; j < image.Height; j++)
    {
        imagecolor = image.GetPixel(i, j);
        imagegray[i, j] = 0.299f * imagecolor.R + 0.587f * imagecolor.G + 0.114f * imagecolor.B;
    }
}