Add offset to IntPtr

Solution 1:

In .net 4 static Add() and Subtract() methods have been added.

IntPtr ptr = IntPtr.Add(oldPtr, 2);

http://msdn.microsoft.com/en-us/library/system.intptr.add.aspx

Solution 2:

I suggest you to use ToInt64() and long to perform your computation. This way you will avoid problem on 64 bits version of the .NET framework.

IntPtr ptr = new IntPtr(oldptr.ToInt64() + 2);

This add a bit of overhead on 32 bits system, but it is safer.

Solution 3:

For pointer arithmetic in C# you should use proper pointers inside an unsafe context:

class PointerArithmetic
{
    unsafe static void Main() 
    {
        int* memory = stackalloc int[30];
        long* difference;
        int* p1 = &memory[4];
        int* p2 = &memory[10];

        difference = (long*)(p2 - p1);

        System.Console.WriteLine("The difference is: {0}", (long)difference);
    }
}

The IntPtr type is for passing around handles or pointers and also for marshalling to languages that support pointers. But it's not for pointer arithmetic.