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How to Marshal an IntPtr containing one more IntPtr

Hi All,
I have a strange problem and due to my inefficiency with IntPtr i am unable to figure it out.

I have an structure something like:

public struct Detail
{
public int age;

public Detail(int _age)
{
age = _age;
}
}

public struct Name
{
public IntPtr names;
}


While trying to Marshal the above code I am marshalling the Object of Detail struct using IntPtr Names: i.e,

Name abc = new Name();

Detail obj = new Detail(2);
int sizeDetailobj = Marshal.SizeOf(typeof(Detail));

abc.names= Marshal.AllocHGlobal(abc.names* Marshal.SizeOf(typeof(Detail)));
Marshal.StructureToPtr(obj, (IntPtr)(abc.names.ToInt32() + sizeDetailobj), false);



Furthurmore I need to pass the object of struct Name which contains the IntPtr to struct Detail along with some other fields.

as,

int size = Marshal.SizeOf(typeof(Name));
IntPtr data = Marshal.AllocHGlobal(size);
Marshal.StructureToPtr(abc, data, true);


Here marshalling happens well without any problem,

For sending the message over Network i am using BEEP Protocol, which converts data into byte[]

as byte[] dataBytes = new byte[size];
Marshal.Copy(data, dataBytes, 0, size);


And at the receiving end while unmarshalling,
I am unmarshalling As;

IntPtr proxyCtx ; //which gets the databyte value

Name namebuf = (Name)Marshal.PtrToStructure(proxyCtx, typeof(Name)); // At this step i got the desired result as IntPtr abc.names

but the IntPtr received itself contains an IntPtr to struct Detail, while unmarshalling;

Detail obj1 = new Detail();
int structSize = Marshal.SizeOf(typeof(Detail));
obj1 = (Detail)Marshal.PtrToStructure(namebuf.names, typeof(Detail));


At this point i was suppose to get the value of age in obj1.age field but instead i am getting some garbage values.

Plz Suggest what i am suppose to do to achieve required value.

Thanks in Advance,
Eric Haas.
Sep 18 '08 #1
0 1905

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