How fix AddressOf requires a relaxed conversation to the delegate error

Question

Sorry, 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

Private Sub SetSetting(ByVal key As String, ByVal value As String)
    KernMobileBusinessLayer.[Global].Settings.SetValue(key, value)
End Sub

Private Function GetSetting(ByVal key As String)
    Return KernMobileBusinessLayer.[Global].Settings.GetString(key)
End Function

Any idea 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.

GetSetting(), as defined above, would return Object, not String. I think max has it right. — rskar, May 23 '11 at 23:08
Use Option Strict On to let the compiler catch these kind of mistakes. — Hans Passant, May 23 '11 at 23:11

score 16 · Accepted Answer · answered May 23 '11 at 23:04

16

probably your GetSetting function must fully match GetSettingDelegate signature:

Private Function GetSetting(ByVal key As String) as String

answered May 23 '11 at 23:04

max

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Thanks. Obvious now! I marked yours as the answer as you answered first. – Steve Chadbourne May 23 '11 at 23:23

score 7 · Answer 2 · answered May 23 '11 at 23:06

your vb code:

Private Function GetSetting(ByVal key As String)

doesn't match the C# delegate definition:

public delegate string GetSettingDelegate(string key);

you should specify a return type in your VB implementation, like this:

Private Function GetSetting(ByVal key As String) As String

How fix AddressOf requires a relaxed conversation to the delegate error

2 Answers2