How to get IntPtr from byte[] in C#

Question

Hi All,

I want to pass a byte[] to a method takes a IntPtr Parameter in c#, is that possible and how.

Thanks All

Answer 1

Not sure about getting an IntPtr to an array, but you can copy the data for use with unmanaged code by using Mashal.Copy:

IntPtr unmanagedPointer = Marshal.AllocHGlobal(bytes.Length);
Marshal.Copy(bytes, 0, unmanagedPointer, bytes.Length);
// Call unmanaged code
Marshal.FreeHGlobal(unmanagedPointer);

Alternatively you could declare a struct with one property and then use Marshal.PtrToStructure, but that would still require allocating unmanaged memory.

Edit: Also, as Tyalis pointed out, you can also use fixed if unsafe code is an option for you

Answer 2

This should work but must be used within an unsafe context:

byte[] buffer = new byte[255];
fixed (byte* p = buffer)
{
    IntPtr ptr = (IntPtr)p;
}

Answer 3

another way:

GCHandle pinnedArray = GCHandle.Alloc(byteArray, GCHandleType.Pinned);
IntPtr pointer = pinnedArray.AddrOfPinnedObject();
//do your stuff
pinnedArray.Free();

Answer 4

In some cases you can use an Int32 type (or Int64) in case of the IntPtr. If you can, another useful class is BitConverter. For what you want you could use BitConverter.ToInt32 for example.