Re: Marshaling Delegates as Struct/Class Members

Furthermore, why can I marshal this class but I can't pin it?

Int32 size = Marshal.SizeOf(typeof(TestObject));
IntPtr ptr = Marshal.AllocCoTaskMem(size);
Marshal.StructureToPtr(testObject, ptr, false);
Marshal.FreeCoTaskMem(ptr);

I would think anything on the managed heap that can be marshalled could be
pinned. Is this wrong?

Thanks

"Bob" <nobody@xxxxxxxxxxx> wrote in message
news:eQx8nST0FHA.3720@xxxxxxxxxxxxxxxxxxxxxxx
>I understand delegates do not need to be pinned, but its the class object
>itself I need pinned. Take this code:
>
>
> [StructLayout(LayoutKind.Sequential)]
> public class TestObject
> {
> [MarshalAs(UnmanagedType.FunctionPtr)]
> public AddDelegate Add;
> [MarshalAs(UnmanagedType.FunctionPtr)]
> public SubtractDelegate Subtract;
>
> public delegate Int32 AddDelegate(Int32 a, Int32 b);
> public delegate Int32 SubtractDelegate(Int32 a, Int32 b);
> }
>
>
> public class Program
> {
> private static void Main(
> String[] args)
> {
> TestObject testObject = new TestObject();
> GCHandle gcHandle = GCHandle.Alloc(testObject,
> GCHandleType.Pinned);
> }
> }
>
>
> The GCHandle.Alloc fails with:
>
>
> System.ArgumentException was unhandled
> Message="Object contains non-primitive or non-blittable data."
> Source="mscorlib"
> StackTrace:
> at System.Runtime.InteropServices.GCHandle.InternalAlloc(Object
> value, GCHandleType type)
> at System.Runtime.InteropServices.GCHandle.Alloc(Object value,
> GCHandleType type)
>
>
> Is there an easy way to marshal delegates as part of a struct? Isn't that
> what UnmanagedType.FunctionPtr is for? I don't want to manage multiple
> objects and manually marshal stuff using
> Marshal.GetFunctionPointerForDelegate? I -really- want to avoid that
> route in this particular project.
>
> Thanks
>
>


.

Relevant Pages

  • Re: Marshaling Delegates as Struct/Class Members
    ... >>I understand delegates do not need to be pinned, but its the class object ... >> public class TestObject ... >> value, GCHandleType type) ... >> Is there an easy way to marshal delegates as part of a struct? ...
    (microsoft.public.dotnet.languages.csharp)
  • Re: Multiple Exception Definitions in One File
    ... > public class ExcepOne extends Exception ... > UseExceps.java:10: an enclosing instance that contains Exceps.ExcepOne ... Non-static inner class objects have a reference to their enclosing outer ... Static inner class object don't have a reference to an enclosing outer class ...
    (comp.lang.java.programmer)
  • Re: Errors when deleting a row in a JTable.
    ... > The code below return a good class object but I've already the same stack ... > public Class getColumnClass(int columnIndex) { ... or TYPE of the wrapper class for some other simple type. ...
    (comp.lang.java)
  • Generic class object?
    ... Is it possible to get the class object from a type parameter? ... public class Test{ ... Regards, ... - Gijs Peek ...
    (comp.lang.java.programmer)