如何删除SharePoint的循环日历项目

据说用SPListItem.Delete不能删除， 偶也不知怎么删除，就看了下系统的实现代码，需要的朋友自己捉摸吧： 

（此代码在Microsoft.SharePoint.WebControls.DeleteItemButton类中） 

private void DeleteFromRecurrenceSeries()
        {
        if ((base.ItemContext.List.BaseTemplate == SPListTemplateType.Events) || ((base.ItemContext.ContentType != null) && base.ItemContext.ContentType.Id.IsChildOf(SPBuiltInContentTypeId.Event)))
        {
        while (true)
        {
        using (IEnumerator enumerator = base.ItemContext.FormContext.FieldControlCollection.GetEnumerator())
        {
        Control control;
        RecurrenceField field;
        goto Label_0023;
        Label_001B:
        field.DeleteExceptionItem();
        return;
        Label_0023:
        if (enumerator.MoveNext())
        {
        goto Label_0036;
        }
        return;
        Label_002E:
        field.DeleteInstanceItem();
        return;
        Label_0036:
        control = (Control) enumerator.Current;
        if (control is RecurrenceField)
        {
        goto Label_005C;
        }
        goto Label_0023;
        Label_004D:
        if (!base.ListItem.IsExceptionId)
        {
        return;
        }
        goto Label_001B;
        Label_005C:
        field = (RecurrenceField) control;
        if (!base.ListItem.IsInstanceId)
        {
        goto Label_004D;
        }
        goto Label_002E;
        }
        }
        }
        }