C# - Fix AddressOf Requires Relaxed Conversation To Delegate Error

This is a mix of C# and VB.Net. I have a C# class with with 2 delegates:
public delegate string GetSettingDelegate(string key);
public event GetSettingDelegate GetSettingEvent;
public delegate void SetSettingDelegate(string key, string value);
public event SetSettingDelegate SetSettingEvent;

In a VB class I add handlers to the event:
AddHandler _gisCtrl.SetSettingEvent, AddressOf SetSetting
AddHandler _gisCtrl.GetSettingEvent, AddressOf GetSetting

When I try and remove the handlers:
RemoveHandler _gisCtrl.SetSettingEvent, AddressOf SetSetting
RemoveHandler _gisCtrl.GetSettingEvent, AddressOf GetSetting

SetSetting is OK but GetSetting throws a warning:
The AddressOf expression has no effect in this context because the method arguments to AddressOf requires a relaxed conversation to the delagate type of the event.

Here are the methods
[Code] .....
How to fix this and why it is thrown in the first place? The 2 delegates/events/methods look similar enough that I don't know why one is OK and one throws a warning.