Question

i have made a listbox datatemplated with button and binded to a textbox.
i would like to be able removing one item by a tap & hold.
my probleme : an invalid operation exception pops

here is my code

Button remover = (Button)sender;

     fileListbox.Items.Remove(remover.Content); 

System.InvalidOperationException was unhandled
Message=Operation not supported on read-only collection.
StackTrace:
à System.Windows.Controls.ItemCollection.RemoveImpl(Object value)
à System.Windows.Controls.ItemCollection.RemoveInternal(Object value)
à System.Windows.PresentationFrameworkCollection1.Remove(Object value)
à proByOrange.views.preDevis.Page1.GestureListener_Tap(Object sender, GestureEventArgs e)
à Microsoft.Phone.Controls.SafeRaise.Raise[T](EventHandler1 eventToRaise, Object sender, GetEventArgs1 getEventArgs)
à Microsoft.Phone.Controls.GestureListener.RaiseGestureEvent[T](Func2 eventGetter, Func`1 argsGetter, Boolean releaseMouseCapture)
à Microsoft.Phone.Controls.GestureListener.ProcessTouchPanelEvents()
à Microsoft.Phone.Controls.GestureListener.TouchComplete()
à Microsoft.Phone.Controls.GestureListener.Touch_FrameReported(Object sender, TouchFrameEventArgs e)
à System.Windows.Input.Touch.OnTouch(Object sender, TouchFrameEventArgs e)
à MS.Internal.JoltHelper.RaiseEvent(IntPtr target, UInt32 eventId, IntPtr coreEventArgs, UInt32 eventArgsTypeIndex)

thx for help

Answer 1

You’re trying to remove an item from a ReadOnly collection. You can’t change such a collection. As you may expect by the name you can only read such a collection, you can’t change it.

You’re title refers to a textbox but your code and stacktrace imply something using an ItemsSource.

If you need to be able to change what is displayed, just make the UI elements readonly and leave the backing collections writeable.

If you can show some example code we can show how to change it appropriately.