Can someone explain the marshal. StructureToPtr

Question

I am having problems with this code:

//Creating a new ImageElement Struct
ImageElement oElement = new UM0516.ImageElement();
//Create a pointer and allocate enough room for the struct type
IntPtr pElement = Marshal.AllocHGlobal(Marshal.SizeOf(new UM0516.ImageElement()));
//Copy the contents of the struct into the allocated memory space
Marshal.StructureToPtr(oElement, pElement, true);
//Function that takes a file pointed to by handle, and does some sweet sweet things
//And returns a loaded struct pointed to by pElement
FILES_GetImageElement(handle, el, out pElement);

This is where I got confused: I will go through the code, and after I call this last function (which should change some bits in memory pointed to by pElement), I see a change in oElement !? I thought that Marshal.StructureToPtr "copies" the data from the managed structure into memory. Similarly, are both places actually the same? The oElement managed structure and allocated memory pointed to by pElement?

Answer 1

This article explains this in detail :

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Answer 2

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pElement oElement ref ( , ), out.