Rewriting Code.

[Jay1b]

Guys

I was hoping someone could please help me. I have a piece of code which works fine, but looks incredibly messy and ideally i'd like to make it easier to reuse.

        For Each np As Control In NavBar1.Controls
            If TypeOf np Is NavBarPanel Then
                If np.Name = "NavPanelCalendar" Then
                    Dim nsb As NavBarSubButton = np.Controls("subBtnUpcoming")
                    AddHandler nsb.Click, AddressOf frmUpcoming
                End If
            End If
        Next

NavBar1 is a usercontrol, which has a collection of NavBarPanels on it, these are custom controls inheriting from the Panel control. The NavBarPanels have a number of NavBarSubButton's on it, which are also custom controls inheriting from the button control.

I have tried both of the following, but they both come up with 'Object reference not set to an instace of a object'.

        'Attempt 1
        Dim nsb2 As NavBarSubButton = NavBar1.Controls("NavPanelCalender").Controls("subBtnUpcoming")
        AddHandler nsb2.Click, AddressOf frmUpcoming

        'Attempt 2
        AddHandler (NavBar1.Controls("NavPanelCalender").Controls("subBtnUpcoming")).Click, AddressOf frmUpcoming

As their are several NavBarPanels, the method i have working looks a little untidy and unwieldy!


Also is there a simple way of using delegates via strings? For example:

AddHandler nsb2.Click, AddressOf frmUpcoming

I would just like to pass the delegate method name into it via code. The delegate name being stored into a database, ideally I would like to store the entire method in a database, but i'm guessing this would be much more complex!



Thanks for any help you may be able to give.

 

[cjard]

I dont really understand what youre talking about but if you want to map strings to objects, you need a dictionary:

Dim dic as Dictionary(Of String, MyWhateverDelegate)

dic("nav1Handler") = New MyWhateverDelegate(nav1HandlerFunction)


Or however it would be written in VB.. this is more like C# (i'm a c# guy, sorry) - thing is that delegates are objects tied to methods but you will need to ahve a comprehensive list of every delegate, the method it ties to, and a string to refer to that delegate.. addhandler should be anle to work with that..

in c# i'd say something like:

foreach BaseControl c in myNavBar.Controls
  c.CommonEvent += dic(c.Name)

to attach a relevant delegate to a named control..

 

[JohnH]

The way you've done in Attempt1/2 works, you must have the names wrong.

AddressOf is short for creating the correct delegate for the event and pointing it to the method, this can be done with reflection:

AddHandler nsb2.Click, System.Delegate.CreateDelegate(GetType(EventHandler), Me, "frmUpcoming")