Structure to IntPtr

Sometimes while working with the unmanaged resouces, we need to convert Marshal-able structure into unmanaged memory and gets its pointer and pass the structure's integer pointer(IntPtr) to unmanaged api.

[StructLayout(LayoutKind.Sequential, Pack=1, CharSet=CharSet.Ansi)]

        struct student

        {

            [MarshalAs(UnmanagedType.LPWStr,SizeConst=10)]

            public string Name;

            [MarshalAs(UnmanagedType.I4)]

            public int RollNo;

            [MarshalAs(UnmanagedType.I4)]

            public int Marks;

        }

To convert structure to Integer pointer we need to use NameSpace: System.Runtime.InteropServices.

Consider the declaration of structure as

            student st = new student();             
            st.Name = "Akash Soni";             
            st.RollNo = 483;             
            st.Marks = 807;

Create object for IntPtr class and allocates memory from the unmanaged memory of specific bytes (which is equals to the size of structure


IntPtr ptrStudent = Marshal.AllocHGlobal(Marshal.SizeOf(st.GetType()));
Now create the unmanaged copy of Structure object 'st' in the unmanaged memory.
Marshal.StructureToPtr(st, ptrStudent, true);

Sample code

public IntPtr ConvertStructureToIntPtr()

   {

      student st = new student();

st.Name = "Akash Soni";     

      st.RollNo = 483;

      st.Marks = 807;

      IntPtr ptrStudent = Marshal.AllocHGlobal(Marshal.SizeOf(st.GetType()));

      Marshal.StructureToPtr(st, ptrStudent, true);

      return ptrStudent;

    }