iOS Question Dynamically change TopRightButton

[jazzzzzzz]

I need to change the toprightbutton icon I wrote the code below but it gives the error below at btnlist.set().Can someone help change the icon in run time? btnlist have 2 items Am trying to change the 2nd item. When i Log btnlist.isreadonly it shows true,I dont know why the array is readonly

            Dim btnList As List = contestImages.TopRightButtons
            Dim btn As BarButton
            btn.InitializeBitmap(LoadBitmap(File.DirAssets,"ic_dashboard.png"),"changeview")
            btnList.Set(1,btn)
            contestImages.TopRightButtons = btnList

changeview
Error occurred on line: 53 (contestImagesCode)
-[__NSArrayI addObject:]: unrecognized selector sent to instance 0x16e06400
Stack Trace: (
  CoreFoundation       <redacted> + 150
  libobjc.A.dylib      objc_exception_throw + 38
  CoreFoundation       <redacted> + 0
  CoreFoundation       <redacted> + 702
  CoreFoundation       _CF_forwarding_prep_0 + 24
  Snap'n'Win           -[B4IList Add:] + 178
  CoreFoundation       <redacted> + 68
  CoreFoundation       <redacted> + 292
  Snap'n'Win           +[B4I runDynamicMethod:method:throwErrorIfMissing:args:] + 1780
  Snap'n'Win           -[B4IShell runVoidMethod] + 210
Snap'n'Win           -[B4IShell raiseEventImpl:method:args::] + 2154
Snap'n'Win           -[B4IShellBI raiseEvent:event:params:] + 1442
Snap'n'Win           __33-[B4I raiseUIEvent:event:params:]_block_invoke + 74
libdispatch.dylib    <redacted> + 10
libdispatch.dylib    <redacted> + 22
libdispatch.dylib    _dispatch_main_queue_callback_4CF + 1532
CoreFoundation       <redacted> + 8
CoreFoundation       <redacted> + 1590
CoreFoundation       CFRunLoopRunSpecific + 516
CoreFoundation       CFRunLoopRunInMode + 108
GraphicsServices     GSEventRunModal + 160
UIKit                UIApplicationMain + 144
Snap'n'Win           main + 108
libdyld.dylib        <redacted> + 2
)

 

[Erel]

What is line #53?

 

[jazzzzzzz]

btnList.Set(1,btn)

 

[Erel]

As this is a read only list you cannot modify it. You need to do:

Dim btnList As List
btnList.Initialize
btnList.AddAll(contestImages.TopRightButtons)

 

[jazzzzzzz]

That Works..