Help Convert to vb.net .net 3.5(VS 2008)

Question

Hello a create a extension method in C# .net 3.5 , with the help of this forum to catch the selection change in cells [msexcel 2007], and i like to now if it is possible convert this to vb.net vs2008?

This is the static method.

 static class ExcelExtensions
    {
        public static IObservable<Excel.Range> WhenCellSelect(this Excel.Workbook WB)
        {
            var t=  Observable.Create<Excel.Range>(observer =>
            {
                Excel.WorkbookEvents_SheetSelectionChangeEventHandler handler =
                    (Object sh,Excel.Range target) =>
                    {
                        observer.OnNext(target);

                    };

                WB.SheetSelectionChange += handler;
                

                return () => WB.SheetSelectionChange -= handler;
            });

            return t;
        }

Thank's,

  sorry for my english

Answer 1

Hi,

Yes, it's possible to write your code in VB.NET instead of C#.  Try asking your question in the VB.NET forum for help converting from C# to VB.NET.

Though your query can be simplified by using Observable.FromEvent or Observable.FromEventPattern.

- Dave

---

http://davesexton.com/blog

Answer 2

Thank's Dave i try the other forum for the conversion.

in C# how to simplify? can you show how or point directions (i newbie in rx thank's).

carman

Answer 3

Hi Carman,

It should look something like this, though I haven't tested it myself.

public static IObservable<Excel.Range> WhenCellSelect(this Excel.Workbook WB)
{
	return Observable.FromEvent<Excel.WorkbookEvents_SheetSelectionChangeEventHandler, Excel.Range>(
		h => WB.SheetSelectionChange += h, 
		h => WB.SheetSelectionChange -= h);
}

- Dave

---

http://davesexton.com/blog

Answer 4

Hi, Dave Thank's to point the direction, but i receved a 

ArgumentException "Error binding to target method." with this StackTrace:

at System.Delegate.CreateDelegate(Type type, Object firstArgument, MethodInfo method, Boolean throwOnBindFailure) at System.Delegate.CreateDelegate(Type type, Object firstArgument, MethodInfo method) at System.Reactive.Linq.Observable.<>c__DisplayClass19c`2.<fromevent>b__19a(IObserver`1 observer) at System.Reactive.AnonymousObservable`1.<>c__DisplayClass1.<subscribe>b__0() at System.Reactive.Concurrency.Scheduler.Invoke(IScheduler scheduler, Action action) at System.Reactive.Concurrency.ScheduledItem`2.InvokeCore() at System.Reactive.Concurrency.ScheduledItem`1.Invoke() at System.Reactive.Concurrency.CurrentThreadScheduler.Trampoline.Run() at System.Reactive.Concurrency.CurrentThreadScheduler.Schedule[TState](TState state, TimeSpan dueTime, Func`3 action) at System.Reactive.Concurrency.CurrentThreadScheduler.Schedule[TState](TState state, Func`3 action) at System.Reactive.Concurrency.Scheduler.Schedule(IScheduler scheduler, Action action) at System.Reactive.AnonymousObservable`1.Subscribe(IObserver`1 observer) at System.ObservableExtensions.Subscribe[TSource](IObservable`1 source, Action`1 onNext, Action`1 onError, Action onCompleted) at System.ObservableExtensions.Subscribe[TSource](IObservable`1 source, Action`1 onNext) at ReactiveProgrammingConsole.InteropLab.Main() in D:\Metropolitano\Escalas\Excel_RX_events_C\Excel_RX_events_C\Program.cs:line 88</subscribe></fromevent>

I suspect that is in signature of method , the second parameter await a TEventArg and I am giving an Excel.Range, it is??

how to wrap the arguments of the excel workbook in TEventsAgs?

I call the method this way

 try
                {
                    WB.WhenCellSelect().Subscribe(cell => Console.WriteLine(cell.Row));
                }
                catch(ArgumentException ex)
                {
                    Console.WriteLine(ex.StackTrace);
                }

Thank's

carman68

Answer 5

Hi,

Try specifying the delegate conversion parameter:

public static IObservable<Excel.Range> WhenCellSelect(this Excel.Workbook WB)
{
	return Observable.FromEvent<Excel.WorkbookEvents_SheetSelectionChangeEventHandler, Excel.Range>(
		h => h,  // delegate conversion
		h => WB.SheetSelectionChange += h, 
		h => WB.SheetSelectionChange -= h);
}

- Dave

---

http://davesexton.com/blog

Answer 6

Thank's Dave

apreciate the support

carman