System.Runtime.InteropServices.COMException when trying to drag and drop between two WPF applications

Question

I have made a WPF application that allows drag and drop of instances of a class I made (FakeNodeViewModel). It works fine when I work with only one instance of my application. But when I use 2 and I try to drag objects from one and drop on the other, I get an exception when dropping:

System.Runtime.InteropServices.COMException: 'Tymed non valide (Exception de HRESULT : 0x80040069 (DV_E_TYMED))'

and the two instances crash. My method to handle drop starts like this:

private void grid_Drop(object sender, DragEventArgs e) {
        if (e.Data.GetDataPresent("fakeNode")) {
            var fakeNodeViewModel = (FakeNodeViewModel)e.Data.GetData("fakeNode");

and the program crash at var fakeNodeViewModel = (FakeNodeViewModel)e.Data.GetData("fakeNode"); I didn't find a lot about this. Does anyone know what happen and how to solve it ?

Answer 1

You should decorate the FakeNodeViewModel class with the System.SerializableAttribute for it be COM serializable:

[Serializable]
public class FakeNodeViewModel
{
    ...
}