Hi, we're currently evaluating Planner.NET if we can use it within our application that has scheduling requirements.  So far, we've been very happy with the functionalities that we're getting from Planner.NET especially recurrence.

Right now, we're almost sure that we'll use your control but we want to verify this quite intermittent exception that we're getting with Planner.NET.

Just a background of what the application is doing when this exception is thrown... basically we have a multithreaded app that "listens" for messages to come into the app.  Messages correspond to appointments in Planner.NET.  When this exception is thrown, my thinking is that there are multiple threads trying to create an appointment in Planner.NET.

My question now is, is there something I should do to make Planner.NET thread-safe?

Please refer to the exception below for details...

Unhandled Exception: System.ArgumentOutOfRangeException: Index was out of range.  Must be non-negative and less than the size of the collection.
Parameter name: index
   at System.Collections.ArrayList.get_Item(Int32 index)
   at MindFusion.Scheduling.WinForms.CellCollection.get_Item(Int32 index)
   at MindFusion.Scheduling.WinForms.ScheduleCell.Draw(DrawContext context)
   at MindFusion.Scheduling.WinForms.Calendar.OnPaint(PaintEventArgs pe)
   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
   at System.Windows.Forms.Control.WmPaint(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.ComponentManager.System.Windows.Forms.UnsafeNativeMethods+I
MsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)

Unfortunately, Planner.NET is not thread-safe. It is your responsibility to ensure that only one thread performs actions on the control's data at a time (such as adding or removing appointments). You can, however, use the Control.Invoke method to execute actions on the thread owning the control's window handle. For example instead of directly calling Calendar.Schedule.Items.Add to add a new appointment to the calendar from a dedicated thread, you can instead use the following technique:

Define a method in your class that adds an appointment to the calendar.

private void AddApp(Appointment a)
{
  calendar.Schedule.Items.Add(a);
} 

Define a delegate corresponding to this method.

private delegate void AppDelegate(Appointment a); 

When you need to add an appointment, you do so by calling Invoke on the Planner.NET control.

calendar.Invoke(new AppDelegate(this.AddApp), new object[] { a }); 

Meppy

Yes, you have to use the same technique whenever you are modifying the calendar data to prevent simultaneous modifications.

Meppy

The control should redraw itself whenever an item is added to it, there is no need to call Invalidate. Still, I have no idea what is the possible reason for this behavior. Would it possible for you to provide me with a sample code that produces this bug?

Meppy

You have to use the techniques described in this topic only if you are modifying the calendar from a thread other than the one that have created it.

Otherwise, I am not really sure what is the actual problem you got.

Meppy