How to get the Exif information of a image

In my system, I want to add a judgment condition, for that  only the Exif image can be uploaded.

To achive it, I should get the Exif information of a image. What should I do?

I tried to write some code to do it, but it still won't work.

System.Drawing.Image img;
System.Drawing.Imaging.PropertyItem prop;
str          filePath;

filePath  = e.get_ImagePath();
img = System.Drawing.Image::FromFile(filePath);
prop = img.GetPropertyItem(？？);